original contents found at ... manual.pdf · 7 2. fuel system the fuel system consists of the...

original contents found at http://www.hillmanimages.com/912/ PDF created by Torbeyns Gilles

2

Manual Table of Contents

The Factory 912 Manual.

1. Engine 2.Fuel System 3.Electrical System 4.Rear Axle and Transmission

1. Engine

• 1.1 ENGINE DESCRIPTION 1.1.1 Numerical Designation Of Cylinders And Main Bearings ....................................11 1.1.2 Cross-Sectional View of Engine ........................................................................... 12 1.1.3 Bottom View......................................................................................................... 14 1.1.4 Crankcase .............................................................................................................. 15 1.1.5 Crankshaft and Connecting Rods.......................................................................... 16 1.1.6 Pistons ................................................................................................................... 17 1.1.7 Cylinders ............................................................................................................... 18 1.1.8 Cylinder Heads...................................................................................................... 19 1.1.9 Cam Shaft...............................................................................................................20 1.1.10 Cooling System................................................................................................... 21 1.1.11 Engine Lubrication System................................................................................. 22 1.1.12 Oil Cooling.......................................................................................................... 23 1.1.13 Oil Pressure Indicator ......................................................................................... 24

• 1.2 ENGINE DISASSEMBLY 1.2.1Disassembling Engine............................................................................................ 25 1.2.2 Remove the Exhaust System................................................................................. 26 1.2.3 Disconnect the Distributor .................................................................................... 27 1.2.4 Remove the Carburetors........................................................................................ 28 1.2.5 Remove the Oil Lines ........................................................................................... 29 1.2.6 Remove Oil Filler ..................................................................................................30 1.2.7 Remove Fan Shroud.............................................................................................. 31 1.2.8 Remove Fuel Pump and Distributor...................................................................... 32 1.2.9 Remove the Rockers ............................................................................................. 33 1.2.10 Remove Intake Manifolds................................................................................... 34 1.2.11 Remove Heads Cylinders and Pistons ................................................................ 35 1.2.12 Remove Crankshaft Pulley.................................................................................. 36 1.2.13 Remove Oil Pump Gears..................................................................................... 37 1.2.14 Remove Third Piece............................................................................................ 38 1.2.15 Remove Clutch.................................................................................................... 39 1.2.16 Remove the Crankshaft........................................................................................40 1.2.17 Remove Bearings and Lifters.............................................................................. 41

• 1.3 ENGINE ASSEMBLY 1.3.1 Engine Assembly Start.......................................................................................... 42 1.3.2 Assemble Crank and Cam Shaft in the Case......................................................... 43 1.3.3 Join the Case ......................................................................................................... 44 1.3.4 Assemble Fly Wheel, Clutch and Third Piece ...................................................... 45 1.3.5 Install Third Piece and Crankshaft Pulley............................................................. 46 1.3.6 Install Distributor and Oil Cooller ........................................................................ 47

3

1.3.7 Install Pistons and Cylinders................................................................................. 48 1.3.8 Install Heads.......................................................................................................... 49 1.3.9 Install Rocker Arms ...............................................................................................50 1.3.10 Finish Assembly.................................................................................................. 51

• 1.4 MANUAL COOLING SYSTEM REMOVAL1.4.1 R/R AIR BLOWER HOUSING 1.4.1 Engine Cooling System......................................................................................... 52 1.4.2 Remove the Air Cleaners and Heating Hoses....................................................... 53 1.4.3 Cooling System - Remove the Breather Hose ...................................................... 54 1.4.4 Cooling System – Removal................................................................................... 55 1.4.5 Cooling System Replace ....................................................................................... 61 1.4.6 Manual Cooling System Replace.......................................................................... 62 1.4.7 Remove Air Blower Housing................................................................................ 62 1.4.8 Install Air Blower.................................................................................................. 66 1.4.9 Manual Replace Cooling Blower.......................................................................... 67 1.4.10 Removing Cooling Blower ................................................................................. 67 1.4.11 Installation........................................................................................................... 68 1.4.12 Removal and Installation of the Cooling Blower Fan ........................................ 69 1.4.13 Fan part number ...................................................................................................70 1.4.14 Fan Mounting Detail ........................................................................................... 72 1.4.15 Removing Air Hoses........................................................................................... 73 1.4.16 Removing Euro Hose .......................................................................................... 74 1.4.17 Euro Hose Adjustment ........................................................................................ 75 1.4.18 Installing Lower Duct with Air Gates................................................................. 76 1.4.19 Installing Air Gate Assembly.............................................................................. 77

• 1.5 CHECKING AND ADJUSTING V-BELT TENSION 1.5.1 Checking V-Belt Tension...................................................................................... 78 1.5.2 Adjusting V-Belt Tension ......................................................................................80

• 1.6 DESCRIPTION OF THE 912 (356 B/T6) HEATING SYSTEM 1.6.1 Functional View of the Heating System (Germany and Sweden) ........................ 82 1.6.2 Functional Description.......................................................................................... 83 1.6.3 Operating description: Heater Control................................................................. 84 1.6.4 Bottom View of Vehicle ....................................................................................... 87 1.6.5 Description of the Export - Type Heating System................................................ 88 1.6.6 Functional View of the Heating System ............................................................... 88 1.6.7 Bottom View of Vehicle - Export Type Heater .................................................... 89

• 1.7 REMOVING AND INSTALLING EXHAUST MUFFLER 1.7.1 Remove Clamps from Heat Exchangers ................................................................90 1.7.2 Remove Muffler.................................................................................................... 91 1.7.3 Installation............................................................................................................. 91

• 1.8 ENGINE LUBRICATION SYSTEM 1.8.1 Oil Circuit in Cold Engine .................................................................................... 92 1.8.2 Oil Circuit at Operating Temperatures.................................................................. 93 1.8.3 Removing Oil Strainer .......................................................................................... 94 1.8.4 Magnetic Oil Filtering........................................................................................... 96 1.8.5 Pressure Relief Valve............................................................................................ 97 1.8.6 Bypass Valve......................................................................................................... 98 1.8.7 Bypass Valve at Start Up ...................................................................................... 99 1.8.8 Bypass Valve When Running ..............................................................................100 1.8.9 Removal Cap Screw............................................................................................ 101 1.8.10 Withdraw Spring and Plunger........................................................................... 102 1.8.11 Remove Oil Cooler ........................................................................................... 103 1.8.12 Remove Oil Pump............................................................................................. 105 1.8.13 Changing Bypass Oil Filter............................................................................... 107

4

• 1.9 HEADS 1.9.1 Removal Rocker Arm Carrier ............................................................................. 108 1.9.2 Remove rocker arm shafts................................................................................... 109 1.9.3 Rocker Arm Installation...................................................................................... 110 1.9.4 Tighten the Rocker Arm Shaft Nuts ................................................................... 111 1.9.5 Disassembling and Reassembling Rocker Arm Carrier...................................... 112 1.9.6 Remove Cylinder Head....................................................................................... 113 1.9.7 Position Cylinder Deflectors............................................................................... 115 1.9.8 Torque the Head Bolts ........................................................................................ 117 1.9.9 Install Pushrods ................................................................................................... 118 1.9.10 Install Rocker Arms .......................................................................................... 119

• 1.10 VALVES 1.10.1 Adjust Valves.................................................................................................... 120 1.10.2 Removing and Installing Valve Springs ........................................................... 121 1.10.3 Valve Spring ..................................................................................................... 122 1.10.3 Checking Valve Guides for Wear ..................................................................... 123 1.10.4 Checking and Reconditioning Valve Seats....................................................... 124 1.10.5 Seating, Inspecting and Testing Valves ............................................................ 128 1.10.6 Adjusting Valve Clearance ............................................................................... 129 1.10.7 Checking Valve Timing and Clearance ............................................................ 132 1.10.8 Removing and installing Valve Guides ............................................................ 133 1.10.9 Removing and installing Valve Seat Inserts ..................................................... 134

• 1.11 CYLINDERS AND PISTONS 1.11.1 Reconditioning and Exchange of Cylinder Heads ............................................ 135 1.11.2 Check Cylinder Head Displacement ................................................................. 135 1.11.3 Removing and Installing Cylinders................................................................... 136 1.11.4 Inspecting Cylinders ......................................................................................... 138 1.11.5 Cylinder Marking.............................................................................................. 139 1.11.6 Removing and Installing Pistons ...................................................................... 140 1.11.7 Remove and Mark Cylinders ............................................................................ 142 1.11.8 Heat Pistons ...................................................................................................... 143 1.11.9 Remove Pins and Rings .................................................................................... 144 1.11.10 Check Proper Size of Rings ............................................................................ 145 1.11.11 Check Ring Fit in Piston ................................................................................. 146 1.11.12 Install Piston Pins............................................................................................ 147 1.11.13 Inspecting Pistons ........................................................................................... 148 1.11.14 Piston Measuring Points.................................................................................. 149 1.11.15Piston Size Table.............................................................................................. 150

• 1.12 CRANKCASE 1.12.1 Crankcase Dissassembly ................................................................................... 151 1.12.2 Remove Oil Pump............................................................................................. 152 1.12.3 Remove Timing Gear Cover ............................................................................. 153 1.12.4 Separate the Case .............................................................................................. 154 1.12.5 Not Correct Position of Timing Gears .............................................................. 155 1.12.6 Install Timing Gear Cover ................................................................................ 156 1.12.7 Disconnect Distributor ...................................................................................... 157 1.12.8 Inspect and Install Pinion Shaft Washer ........................................................... 158 1.12.9 Install Pinion Shaft............................................................................................ 159 1.12.10 Insert Spring in Pinion Shaft........................................................................... 160 1.12.11 Install Bearing 4 Oil Seal ................................................................................ 161 1.12.12 Deform Oil Seal .............................................................................................. 162 1.12.13 Pry Oil Seal ..................................................................................................... 163 1.12.14 Heat and Remove Bearing 4 ........................................................................... 164

5

1.12.15 Install Oil Seal................................................................................................. 165 1.12.16 Timing Gear Cover R/R.................................................................................. 166 1.12.17 Timing Gear Cover O-Rings........................................................................... 167 1.12.18 Rubber Plugs on Timing Gear Cover.............................................................. 168 1.12.19 Flywheel R/R .................................................................................................. 169 1.12.20 Flywheel Installation....................................................................................... 171 1.12.21 Dowel Pin Position.......................................................................................... 172 1.12.22 Reconditioning Flywheel ................................................................................ 173 1.12.23 Crankshaft Pulley Diagram............................................................................. 174 1.12.24 Flywheel Oil Seal R/R .................................................................................... 175 1.12.25Camshaft Remove / Install............................................................................... 176 1.12.26 Timing Gear Position ...................................................................................... 177 1.12.27 Camshaft Gear Marking.................................................................................. 178 1.12.28 Install Crankshaft ............................................................................................ 179 1.12.29 Connecting Rods R/R...................................................................................... 180 1.12.30 Torque Connecting Rods ................................................................................ 181 1.12.31 Tap to Rods Relieve Stress ............................................................................. 182 1.12.32 Check Clearance ............................................................................................. 183 1.12.33 Installing Connecting Rod .............................................................................. 184 1.12.34 Measuring and Realigning Connecting Rods.................................................. 184 1.12.35 Checking for Twisted Connecting Rods ......................................................... 185

• 1.13 CRANKSHAFT 1.13.1 Crankshaft Disassembly.................................................................................... 187 1.13.2 Crankshaft Reassembly..................................................................................... 188 1.13.3 Crankshaft End Play.......................................................................................... 189 1.13.4 Measure End Play ............................................................................................. 190 1.13.5 Calculating End Play......................................................................................... 191 1.13.6 Reconditioning Crankshaft ............................................................................... 193 1.13.7 Measuring Bearing Inserts ................................................................................ 196

• 1.14 CLUTCH 1.14.1 Diagram of the Clutch....................................................................................... 197 1.14.2 Remove Clutch.................................................................................................. 198 1.14.3 Clutch Installation ............................................................................................. 199 1.14.4 Measure Clutch Thickness .................................................................................200 1.14.5 Check Clutch Disk for Runout.......................................................................... 201 1.14.6 Inspecting Clutch Assembly ............................................................................. 202 1.14.7 Check Pressure Plate......................................................................................... 202 1.14.8 Check Clutch Attachment Points ...................................................................... 203 1.14.9 Check Wear of Rivet Heads.............................................................................. 204 1.14.10 Adjusting Clutch ............................................................................................. 205 1.14.11 Adjust Clutch Free-Play at Control Lever ...................................................... 205 1.14.12 Adjust Free-Play at Clutch Pedal .................................................................... 206 1.14.13 Adjusting Clutch Travel.................................................................................. 207 1.14.14 Adjusting Clutch Pedal Travel........................................................................ 208

• 1.15 TOLERANCES AND WEAR LIMITS 1.15.1 Cylinder Seat Depth in Cylinder Head ............................................................. 209 1.15.2 Cylinder Bore Ovality....................................................................................... 210 1.15.3 Piston Ring Gap ................................................................................................ 210 1.15.4 Piston Pin to Connecting Rod Clearance .......................................................... 211 1.15.5 Crank Pin to Connecting Rod Clearance .......................................................... 211 1.15.6 Crankshaft to Main Bearing Clearance............................................................. 212 1.15.7 Crankshaft Runout ............................................................................................ 213 1.15.8 Crankshaft to Crankshaft Thrust Bearing ......................................................... 214 1.15.9 Diagram of the Clutch....................................................................................... 215

6

1.15.10 Crankshaft Pulley Runout ............................................................................... 216 1.15.11 Camshaft Bearing Clearance........................................................................... 217 1.15.12 Camshaft End Play at Thrust End................................................................... 218 1.15.13 Camshaft Center Bearing Runout ................................................................... 219 1.15.14 Lateral Runout................................................................................................. 219 1.15.15 Vertical Runout ............................................................................................... 220 1.15.16 Flywheel Lateral Runout................................................................................. 220 1.15.17 Flywheel Vertical Runout ............................................................................... 221 1.15.18 Flywheel Diam of Oil Sealing Surface ........................................................... 222 1.15.19 Flywheel Depth of Recess to Web.................................................................. 223 1.15.20 Flywheel Web Thickness ................................................................................ 224 1.15.21 Flywheel Width of Oil Sealing Area............................................................... 224 1.15.22 Valve Guide Clearances.................................................................................. 225 1.15.23 Valve Seat ....................................................................................................... 226 1.15.24 Valve Springs.................................................................................................. 227 1.15.25 Valve Spring Lengths...................................................................................... 228 1.15.26 Valve Lifter Dimensions................................................................................. 229 1.15 27 Oil Pump ......................................................................................................... 230 1.15.28 Pressure Relief Spring..................................................................................... 231 1.15.29 Torque Values for Bolts and Nuts .................................................................. 232

7

2. Fuel System

The fuel system consists of the carburetors, fuel pump, fuel tank and fuel lines. • 2.1 FUEL SYSTEM DESCRIPTION................................................................................ 233 • 2.2 DESCRIPTION OF THE SOLEX 40 P II - 4 CARBURETOR

2.2.1 Solex 40 P II-4 Solid Shaft Parts list................................................................... 234 2.2.2 Solex 40 PII-4 Split Shaft Parts List ................................................................... 238 2.2.3 Solex 40 P II-4 Diagram ..................................................................................... 243 2.2.4 Solex 40 P II-4 Cross Section ............................................................................. 244 2.2.5 Solex 40 P II-4 Lateral Cross Section ................................................................. 245 2.2.6 The Float Chamber.............................................................................................. 246 2.2.7 Idle Metering....................................................................................................... 247 2.2.8 Intermediate Metering......................................................................................... 248 2.2.9 Partial Load ......................................................................................................... 249 2.2.10 Full Power with Enrichment ............................................................................. 250 2.2.11 Acceleration ...................................................................................................... 251 2.2.12 Check Valve ...................................................................................................... 252 2.2.13 Carburetor Specifications2.2 Solex Carburetors .............................................. 253

• 2.3 REPAIR PROCEDURES 2.3.1 Removing and Installing Fuel Line..................................................................... 254 2.3.2 Removing and Installing Carburetor ................................................................... 255 2.3.3 Cleaning Carburetor ............................................................................................ 256 2.3.4 Disassembling and Reassembling Carburetor..................................................... 257 2.3.5 Inspection and Reassembly ................................................................................. 258 2.3.6 Adjusting Injection Quantity............................................................................... 259 2.3.7 Adjusting Idle Speed ........................................................................................... 261 2.3.8 Checking Carburetor Float Level........................................................................ 263 2.3.9 Removing and Installing Air Cleaners ................................................................ 265 2.3.10 Removing and Installing Intake Duct ............................................................... 266 2.3.11 Removing and Installing Throttle Linkage ....................................................... 266 2.3.12 Adjusting Throttle Linkage ............................................................................... 267 2.3.13 Carburetor Service Diagnosis ........................................................................... 267

• 2.4 FUEL PUMP

2.4.1 Fuel Pump Schematic.......................................................................................... 269 2.4.2 Schematic of Manual Fuel Pump Drive .............................................................. 271 2.4.3 Pump Side of Mechanical Fuel Pump................................................................. 272 2.4.4 Actuating Side of Mechanical Fuel Pump .......................................................... 273 2.4.5 Testing Pump Pressure ........................................................................................ 274 2.4.6 Removing and Installing Fuel Pump................................................................... 275 2.4.7 Reconditioning Fuel Pump.................................................................................. 277

8

3. Electrical System

3.1 ELECTRICAL SYSTEM DESCRIPTION………………………………………..280 3.2 LAMPS AND FUSES……………………………………………………………..282 3.3 GENERATOR DESCRIPTION………………………………………………..….284

3.3.1 Changing Ignition Warning Light……………………………………….287 3.3.2 Checking the Generator………………………………………………….288 3.3.3 Removing and Refitting Regulator Switch………………………………290 3.3.4 Checking Carbon Brushes and commutator…...………………………....290 3.3.5 Removing and Refitting Generator……………......………………..........291 3.3.6 Dismantling and Reassembling Generator…………………………...…..291 3.3.7 Checking Armature…………………………………………………...….292 3.3.8 Generator Faults and their Elimination…………………………………..295

• 3.4 ENGINE STARTER DESCRIPTION……………………………………………..296

4. Rear Axle and Transmission

• 4.1 ADJUSTING GEARSHIFT LINKAGE 4.1.1 Remove Cover…………………………………………………………...299 4.1.2 Loosen Hex Bolt…………………………………………………………299 4.1.3 Set Selector………………………………………………………………300

9

1. ENGINE 1.1 912 ENGINE DESCRIPTION

The engine shown is for a 1965-1966 SWB car and has the German heating system. There is no smog equipment on the car other than crank case ventilation from the oil filler can to the right hand head. In late 1966 the motor mount changed from the flat plate shown to a U-shaped channel with 4 rubber motor mounts. The arrow points to the engine serial number.

As you already know, there is great similarity between the 912 and 1600 SC engine. Thus you will find many familiar instructions in this Service Guide for the 912 engine. Chassis design of the 912 Porsche is basically the same as that of the Type-911. Consequently, you may apply the workshop manual for the Type 911, in combination with this Service Guide for the 912 engine, to the 912 Porsche as well. The choice of arranging your Porsche manuals is being left to your discretion. You may remove from your 911'Workshop Manual the chapter dealing with the

10

911 engine and replace it with this Service Guide for the 912 engine, thus having a complete 912 Workshop Manual; you may supplement your 911 Workshop Manual with this Service Guide for the 912 engine to have both types in a single book; or you may retain your 911 Workshop Manual and this Service Guide for 912 engines in separate books to have ample space in each book for the inclusion of notes and supplements. The procedures, tool application and identification have, of course, been adopted from the 911 Workshop Manual.

11

1.1.1 Numerical Designation Of Cylinders And Main Bearings

Here we see a diagram of the engine showing how the cylinders are numbered. One additional piece of information is the cylinder firing order: 1-4-3-2

Cylinders

Viewed in direction of travel;

• Cylinder I: Front, right side • Cylinder II; Rear, right side • Cylinder III: Front, left side • Cylinder IV: Rear, left side

MAIN BEARINGS

Bearing

1. Inside diameter 50 mm, sleeve insert (flywheel-end) 2. Inside diameter 55 mm, split insert 3. Inside diameter 55 mm, split insert 4. Inside diameter 40 mm, sleeve insert (at crankshaft pulley)

12

1.1.2 Cross-Sectional View of Engine

Fig. 3

The figure shows a cutaway view of the engine with major items identified.

Cross-Sectional View of the Engine

1. Clutch 2. Flywheel 3. Main bearing journal. Bearing 2 4. Cooling air inlet 5. Cooling blower impeller 6. A ir blower housing 7. Oil filler 8. Generator 9. Generator carrier 10. V-belt 11. Spacers, adjusting V-belt tension 12. Bearing sleeve. Bearing 4 13. Pulley retaining nut 14. Flywheel gland nut 15. Cylinders and pistons 16. Camshaft 17. Oil strainer 18. Magnetic filtering el< 19. Connecting rod bearii

13

20. Oil suction tube 21. Timing gear 22. Oil pump 23. Camshaft drive gear 24. Distributor drive gear 25. Crankshaft pulley

14

1.1.3 Bottom View

Fig. 5

The bottom view again shows the German edition of the 912 with different heater components including modified heat exchangers and muffler. This version was used for Sweden and Germany. The rest of the world recieved 'flapper boxes' patterned after the VW Beetle of the period. Notice also that the mounting system for the exhaust system is different with what appears to be connections to the third piece of the engine case.

Bottom View of Vehicle

1. Transmission filler plug 2. Transmission drain plug 3. Transmission 4. Clutch control lever 5. Engine drain plug 6. Oil strainer cover 7. Crankcase 8. Exhaust muffler 9. Forward power train carrier 10. Suspension control arm 11. Heating air control gates 12. Axle shaft 13. Shock absorber 14. Heat exchanger 15. Tail pipe

15

1.1.4 Crankcase

We often refer to the timing gear cover as the 'third piece'. The manual description is interesting because there it includes assembly instructions which seem out of place in this section of the manual.

The cast - light alloy crankcase consists of two crankcase sections and a timing gear cover. It is possible to replace the timing gear cover alone, if the dowel pin bores are bored to 8,1 mm diameter. before assembling. When assembling, first tighten the screw lightly, then while turning the crankshaft tighten to the correct torque.

16

1.1.5 Crankshaft and Connecting Rods

Fig. 7

Here we see the crankshaft and connecting rods. The four connecting rods ride on the plain-bearing crankshaft in lead-bronze bearing inserts. All connecting rods have bronze piston pin bushings. All crankshaft journals are soft nitrided. Bearings 2 and 3 (seen from the clutch-end) are split-sleeve inserts. Bearing 4 may be replaced without disassembling the crankcase by removing the timing gear cover. Bearing 1 also takes up the crankshaft thrust. The flywheel, which also carries the starter gear teeth, is attached to the crankshaft by means of a gland nut and fixed in position by 8 aligning dowel pins. The camshaft gear and the distributor drive gear are locked to the crankshaft through Woodruff keys. The crankshaft pulley is attached to the crankshaft through a hex bolt and locked with a Woodruff key. The crankshaft is sealed in the crankcase through oil seals located at the flywheel and crankshaft pulley ends.

17

1.1.6 Pistons

Fig. 8

The light-alloy pistons in the Type 912 engine have 3 piston rings each, the lowest ring being the oil scraper. The piston pins float in the connecting rod bushings; they are contained within the pistons through the use of circlips.

18

1.1.7 Cylinders

A big bore kit has larger diameter pistons, from 83.5mm to 86mm. The cylinder description is, of course, for the stock cylinder which are not suitable to be bored out to accept the larger diameter pistons. Cast iron cylinders used for the 356C engines are often used for this purpose.

The cylinders are made of carbon steel encased with light-alloy cooling fins.

19

1.1.8 Cylinder Heads

The clylinder heads are symetrical left and right. The combustion chamber needs to be modified for the narrower sealing surface of big bore cylinders.

Each bank of two cylinders has a common, heavily finned, cast light alloy cylinder head with shrunk-in valve seats and valve guides. Helicoil inserts are used as spark plug seats. The cylinder head accommodates the valves in a "V" arrangement. No gasket is used between the cylinder head and the cylinders.

20

1.1.9 Cam Shaft

The 3-journal camshaft rides on the base metal of the crankcase. Camshaft drive is through helical gears; the timing gear is of light alloy. Valve timing is effected through cams, valve lifters, push rods, and rocker arms. Each cam alternately actuates one valve of two opposing cylinders. The exhaust valves are cased with high-grade chrome-nickel steel.

21

1.1.10 Cooling System

Fig. 12

The engine is cooled by an air blower. The blower impeller is situated on the extended generator shaft which is driven by the crankshaft over a V-belt. The blower draws cooling air through an intake in the blower housing and forces it over the heavily finned cylinders and cylinders heads. The cooling air is guided by deflector baffles.

22

1.1.11 Engine Lubrication System

Fig. 13

The engine oil supply is in the bottom of the case, normal with wet sump lubrication systems and unlike the 911.

Engine lubrication is effected through a forced feed system and includes an oil cooling provision. The oil pump is situated in the timing gear cover and is driven by the camshaft. The oil is picked up from the lowest point in the crankcase and forced into the oil cooler and the oil galleries. Part of the oil is forced through the main bearings into the drilled oil galleries in the crankshaft and lubricates the connecting rod bearings. A second part of the oil lubricates the camshaft bearings, and still another part passes through the hollow pushrods to the rocker arm bearings, also lubricating the valve shafts. Cylinder walls, pistons, and piston pins are lubricated through oil splash. Oil draining from the points of lubrication collects in the bottom of the crankcase where it passes through an oil strainer and a magnetic filtering element, both entrapping foreign matter that may be suspended in the oil. A bypass oil filter additionally cleans the circulating oil.

23

1.1.12 Oil Cooling

The stock oil cooler is made of steel and is associated with cracks in the case. An aluminum replacement is available which has better head transfer characteristicsand is lighter weight, putting less stress on the case.

The oil cooler is mounted on the crankcase in the stream of cooling air forced through by the cooling blower. The oil cooler is so inserted into the oil circuit that the oil pumped by the oil pump must pass through the oil cooler before it reaches the points of lubrication. Cooling of the oil ensures that it retains its full lubricating qualities even in very warm weather and under constant operating loads. When the oil is cold and thick flowing, a pressure relief valve permits the oil to bypass the oil cooler and flow directly into the oil galleries.

24

1.1.13 Oil Pressure Indicator

Fig. 15

There are two electrical sending units shown in the diagram. The vertical one is the pressure sender and the horizontal one behind it is the temperature sender. It is not uncommon for these to fail and to leak oil.

A pressure-actuated switch is connected to the pressure gallery between the pump and oil cooler. The switch opens the electric circuit of the oil pressure indicator lamp at a pressure between 0.3 and 0. 6 aim (4. 5 - 8. 8 psi), causing the lamp to go out. The lamp glows when the ignition is turned on and the oil pressure is low.

25

1.2 MANUAL ENGINE DISASSEMBLY

1.2.1 Disassembling Engine

Fig. 17

The maunal calls out some special tools that are used for Dissembling and Assembling the engine. It is assumed in this series that the engine has been removed from the car.

Special Tools:

• P la - Electric piston heater • P 2 - Piston pin mandrel • P 8a - Piston ring compressor • P 42 - Torque wrench, 50 mkg (362 lbs/ft), flywheel tightening and

loosening • P 44 - Hex socket, 36 mm, flywheel tightening and loosening • VW 307 - Engine and transmission bench mount

Disassembly Disassemble the engine in the following order:

• 1. Drain engine oil.

26

1.2.2 Remove the Exhaust System

Fig. 18

The shields are the horizontal sheet metal. Removing the exhaust system is often difficult after years of use but replacement parts are still being made, so a cut-off saw may be considered.

• 2. Remove engine front, rear and side Shields. • 3. Remove exhaust muffler and exhaust pipes with heat exchangers.

27

1.2.3 Disconnect the Distributor

Fig. 17

• 4. Detach cable connecting coil and distributor, remove distributor cover.

28

1.2.4 Remove the Carburetors

Fig. 19

• 5. Remove air cleaners. • 6. Remove fuel lines and throttle linkage. • 7. Remove carburetors (2 Fu). • 8. Remove V-belt.

29

1.2.5 Remove the Oil Lines

Fig. 20

• 9. Detach oil lines from bypass oil filter.

30

1.2.6 Remove Oil Filler

Fig. 21

The picture shows the Euro fan shroud and a braket used to hold the air hose. This is not included on the U.S. model.

• 10. Remove oil filler.

31

1.2.7 Remove Fan Shroud

Fig. 22

Not mentioned are many details including the generator strap and that the generator can remain attached to the fan shroud for this operation.

• 11. Remove shroud retaining bolts. • 12. Unfasten generator, • 13. Withdraw blower housing. (See cooling) • 14. Remove cylinder shrouds and, in cases involving the Export heater,

lower air ducts. (See cooling)

32

1.2.8 Remove Fuel Pump and Distributor

Fig. 23

The picture shows only the generator carrier.

• 15. Remove fuel pump (13 Fu). • 16. Remove distributor and distributor pinion shaft. • 17. Remove generator carrier.

33

1.2.9 Remove the Rockers

Fig. 24

The rockers cover some of the access to the head studs, so must be removed first.

• 18. Remove rocker box Covers. • 19. Remove rocker arms. • 20. Remove rocker arm carriers.

34

1.2.10 Remove Intake Manifolds

Fig. 25

• 21. Pull out pushrods. • 22. Remove intake ducts.

35

1.2.11 Remove Heads Cylinders and Pistons

It would be good to take pictures of each stage of dissassembly to guide in reassembly.

• 23. Remove cylinder heads • 24. Remove pushrod tubes and air deflector baffles. • 25. Remove cylinders and pistons, marking each for reassembly.

36

1.2.12 Remove Crankshaft Pulley

912_fig_27

Notice that the U.S. models did not include the exhaust muffler brackets that are seen in this picture.

• 26. Remove crankshaft pulley, withdraw Woodruff key. • 27. Remove exhaust muffler brackets.

37

1.2.13 Remove Oil Pump Gears

Fig. 28

• 28. Remove oil pump cover. • 29. Withdraw oil pump gears.

38

1.2.14 Remove Third Piece

Fig. 29

• 30. Remove timing gear cover.

39

1.2.15 Remove Clutch

Fig. 30

• 31. Remove clutch.

40

1.2.16 Remove the Crankshaft

• 32. Remove flywheel. • 33. Remove oil strainer cover and oil strainer. • 34. Disassemble crankcase. • 35. Withdraw crankshaft and camshaft.

41

1.2.17 Remove Bearings and Lifters

Fig. 32

• 36. Withdraw valve lifters. • 37. Withdraw bearing 2 and 3 inserts. • 38. Remove oil seal, deflector, bearing 4 and bypass valve from the

timing gear cover.

42

1.3 MANUAL - ENGINE ASSEMBLY

1.3.1 Engine Assembly Start

Fig. 33

Now we can start putting the engine back together.

Reassemble engine in reversed order of the above, noting the following points:

• 1. Thoroughly clean crankcase parts, flush oil passages with clean gasoline, install oil drain plug.

• 2. Install bearing inserts for Bearing 2 and 3 into the right and left crankcase halves.

• 3. Lubricate valve lifters with graphite oil and install.

43

1.3.2 Assemble Crank and Cam Shaft in the Case

• 4. Check dowel pin in Bearing 1 for firm seating. • 5. Place assembled crankshaft into crankcase half. • 6. Place cam shaft into crankcase half.

44

1.3.3 Join the Case

Fig. 35

• 7. Insert thrust washer and oil seal. • 8. Install camshaft end plus,. • 9. Join both crankcase halves.

45

1.3.4 Assemble Fly Wheel, Clutch and Third Piece

Fig. 36

• 10. Install flywheel. • 11. Install clutch. • 12. Install oil strainer and oil strainer cover. • 13. Install Bearing 4, deflector, oil seal, bypass valve, counter-pressure

oil line, and oil pump, into the timing gear cover. Install timing gear cover, check Bearing 4 set screw for firm seating.

46

1.3.5 Install Third Piece and Crankshaft Pulley

Fig. 37

• 14. Install crankshaft pulley shield. • 15. Install crankshaft pulley. • 16. Insert distributor pinion shaft with thrust washer and spring.

47

1.3.6 Install Distributor and Oil Cooller

Fig. 38

• 17. Install distributor. • 18. Install fuel pump. • 19. Install oil cooler.

48

1.3.7 Install Pistons and Cylinders

Fig 39

• 20. Install pistons and cylinders. Do not fail to install cylinder base gaskets.

49

1.3.8 Install Heads

Fig. 40

• 21. Install deflector baffles with supporting springs. • 22. Install pushrod covers with gaskets. • 23. Insert cylinder head and tighten. Note proper location of cylinder

shrouds. • 24. Squirt oil into pushrods and insert in place.

50

1.3.9 Install Rocker Arms

• 25. install rocker arm carriers. • 26. Adjust valve clearance, install rocker box covers.

51

1.3.10 Finish Assembly

Fig. 42

• 27. Install spark plugs. • 28. Install intake manifolds using new gaskets (clean the gasket

surface). • 29. Insert blower housing with generator. • 30. Install cylinder shrouds. • 31. Install fuel pump shield. • 32. Fasten lower air ducts (Export heater). • 33. Install cylinder end shrouds. • 34. Attach oil lines to bypass oil filter and oil- pressure switch, check for

leakage. • 35. Fasten generator strap, spin generator shaft to ensure that blower

impeller is not binding. • 36. Install V-belt. • 37. Connect cable to Terminal I connecting coil and distributor. • 38. Install carburetors, throttle linkage, and fuel line. • 39. Install oil filler. • 40. Install air cleaners. • 41. Connect ignition leads. • 42. Install exhaust muffler, connecting with heat exchangers. • 43. Fill engine oil, run engine briefly and recheck oil level, replenish if

necessary.

52

1.4 MANUAL COOLING SYSTEM REMOVAL

1.4.1 Engine Cooling System

Fig. 43

1. Engine front shield 2. Engine side shield 3. Cylinder shroud 4. Blower housing 5. Engine side shield 6. Engine rear shield

53

1.4.2 Remove the Air Cleaners and Heating Hoses

Fig. 44

• 1. Remove air cleaners from both carburetors. • 2. Loosen the right and left heating hose attaching clamps. • 3. Loosen the center hose clamp and, pushing it to the right, remove

from the attaching tab.

54

1.4.3 Cooling System - Remove the Breather Hose

• 4. Remove transverse engine carrier (4 bolts); in cars equipped with the newer version of the carrier also remove the carrier plate.

• 5. Remove crankcase breather hi from breather.

55

1.4.4 Cooling System - Removal

These instructions apply to the Euro heating system.

• 6. Remove heating hose connecting flange from the air blower housing. • 7. Remove short connecting hose from rear engine cover panel.

• 8. Remove retaining screws from the engine rear shield and withdraw shield by pulling rear ward.

• 9. Remove side shield on right and left sides, withdraw together with breather.

56

• 10. Remove engine front shield. • 11. Remove exhaust muffler. • 12. Remove heat exchanger

• 13. Detach cables connecting the distributor and coil, and remove distributor cover.

57

• 14. Remove caruretors (2 Fu). • 15. Remove V-belt. • 16. Remove oil breather.

58


• 18. Remove Distributor. • 19. Remove Fuel Pump.

59

• 20. Remove both transverse carrier supposts

• 21. Remove cover shrouds. • 22. Unfasten generator retaing strap. • 23. Withdraw blower housing.

60

• 24. Remove cylinder shrouds and lower air duct. • 25. After removing the cylinder heads, withdraw deflector baffles and

supporting springs. • 26. Using a puller, withdraw crankshaft pulley and remove pulley shield.

61

1.4.5 Cooling System Replace

The cooling air shroud should be reinstalled in reversed order of the above, making certain that the shrouds are well fitted and the spark plug rubber covers properly seated. Torn, porous, or otherwise defective rubber gaskets must be replaced, A 11 rubber parts should be kept free of grease and oil.

Particular attention must be given to proper placement of the deflector baffles. To the left is Deflector baffle for Cyl 3 and 4 To the right is Deflector baffle for Cyl 1 and 2

62

1.4.6 Manual Cooling System Replace

1.4.7 Remove Air Blower Housing

• 1. Detach throttle linkage from both throttle control levers,

63

• 2. Remove carburetors and fuel supply line. • 3. Detach throttle control linkage. • 4. Remove generator retaining strap.

64


65

• 6. Detach ignition leads from spark plugs, and cable connecting distributor with coil, remove distributor cover.

• 7. Remove retaining screws from cylinder end and side shrouds. • 8. Detach heating air connecting flange from air blower housing.

66

9. Remove air blower housing by pulling it up.

1.4.8 Install Air Blower Install the air blower housing in reversed order of the above by noting the following points: 1. The cover shrouds must join their counterparts with good fit to preclude loss of cooling air. 2. With engine installed, properly connect the generator cables. 3. Adjust carburetor linkage. 4. Check gasket at the oil filler stack, replace if necessary.

67

1.4.9 Manual Replace Cooling Blower

The detachable generator carrier permits withdrawal of the generator and blower impeller assembly without removal of the entire air blower housing. The work procedure is as follows:

1.4.10 Removing Cooling Blower

• 1. Remove V-belt and detach generator cables. • 2. Loosen generator retaining strap. • 3. Remove oil filler stack. • 4. Remove bypass oil filter assembly. • 5. Remove retaining bolts from the blower housing cover.

68

• 6. Remove generator carrier, cover the crankcase opening to prevent entry of foreign matter.

• 7. Withdraw the generator and blower impeller assembly.

1.4.11 Installation The installation is accomplished in reversed order of the above by noting the following points:

1. Properly connect generator cables (brown cable to Terminal D-, black cable to Terminal DF, red cable to Terminal D+).

2. Insert new gasket between the generator carrier and timing gear cover. 3. Check for proper V-belt alignment between the generator and crankshaft

pulleys and correct be repositioning the generator in its cradle; however, make certain that no tension is created between the blower housing cover and the blower housing when the retaining screws are tightened.

69

1.4.12 Removal and Installation of the Cooling Blower Fan

Special Tools P 42 Torque wrench, or VW 118 Torque wrench P 44 Hex socket. 36 mm, for P 42,

Removal

Diagram of the fan installation to the generator shaft.

1. Remove air blower. 2. Mount generator in a vice by fastening it by the pulley

spindle through plastic or aluminum grip protectors. 3. Unscrew the special impeller nut and withdraw impeller

together with its back shield.

Installation

1. Note the proper arrangement of spacers. 2. Position impeller shield. 3. Tighten the special impeller nut to 10 mkp (72. 3 lbs/ft). 4. The clearance between the blower housing cover and impeller should be

approximately 3 mm (1/8 in.). 5. When turning, the impeller should not strike the housing cover.

http://www.hillmanimages.com/912/912_fig_64.html


70

1.4.13 Fan part number

Parts Manual

There is a difference between the parts for the small and larger generator.

49 900.028.008.01 Spring Washer. B 6 DIN 137 bost. 5

50 900.075.010.02 Hexagon Srew M 6x12 DIN 933-8G 5

52 616.106.181.00 Nut for fan for generator 350 W 1

(52) 547.09.303 Nut for fan for generator 420 W 2

53 616.106.011.00 Fan for generator 350 W 1

(53) 616.106.023.00 Fan for generator 420 W 1

54 546.06.204 Cover plate for generator 350 W 1

(54) 616.106.337.00 Cover plate for generator 420 W 1

55 546.06.202 Washer 1

56 546.06.203 Carrier plate for generator 350 W 1

57 539.09.314 Washer 19

71

58 539.06.201 Hub for fan for generator 350 W 1

(58) 616.106.201.00 Hub for fan for generator 420 W 1

59 539.06.102 Reinforcement flange for generator 350 W 1

(59) 616.106.339.00 Reinforcement flange for fan cover for generator 350 W

1

- 616.106.115.00 Cover plate for generator 420 W 1

60 616.106.125.00 Distance ring 1

61 616.106.105.01 Cover for fan housing, generator 350 W 1

(61) 616.106.024.00 Cover for fan housing, generator 420 W 1

72

1.4.14 Fan Mounting Detail

Diagram of the fan installation to the generator shaft.

1. Thick washer 2. Impeller back shield 3. Thick washer 4. Generator shaft 5. Blower housing cover 6. Special impeller nut 7. Impeller 8. Spacers (as needed, 2-5 each) 9. Impeller hub 10. Generator

73

Manual Replace Hoses, Ducts and Gates

Air Hose Connecting Duct

Removal

1.4.15 Removing Air Hoses

• 1. Detach heating hose from connecting duct. • 2. Detach breather hose from breather.

74

1.4.16 Removing Euro Hose

• 3. Remove retaining nut and bolt from the connecting duct. Push rubber hose section down and off the duct, pull duct diagonally upward.

75

1.4.17 Euro Hose Adjustment

• 1. Check adjustment of the counter-nut used for fastening the connecting duet. The nut must be screwed in deep enough to permit flush alignment of the connecting duct with the blower housing without deformation of the duct when tightened at the attaching points.

• 2. Inspect heating hose and breather hose for airtightness and possible damage.

76

1.4.18 Installing Lower Duct with Air Gates

Export Heater

The air gates, located in the lower air duct must be so adjusted that they perform the opening and closing functions in unison. Ensure that the large air gate flaps are positioned approx 10 mm (2/5in.) from the bottom of the ducts when the small air gate flap is fully closed. Upon mounting the lower ducts at the engine, check for proper functioning of the air gates and readjust if necessary.

77

1.4.19 Installing Air Gate Assembly

The following points should be observed when installing the air gate assembly:

Heating Hose attachment

Check for proper seating of the 2,5 mm-thick cork gasket. Check heating hose attachment for air-tightness and firm seating with the help of the hose clamp.

78

1.5 MANUAL CHECKING AND ADJUSTING V-BELT TENSION

1.5.1 Checking V-Belt Tension

General The generator and air blower are driven by a V-belt. The loads created by these two accessory units impose considerable stresses upon the belt at high engine speeds and, especially, during downshifts. For this reason, we recommend that the V-belt tension be frequently checked and adjusted when necessary. Loose V-belt tension results in belt slippage in the pulley causing the engine to run hot. excessively high V-belt tension leads to belt failure and, possibly, premature wear of the generator bearings.

79

When servicing the engine, care should be excercised to keep oil and grease off the V-belt; oily V-belts should be washed in a soap or detergent solution and then thoroughly rinsed in clear water although it is always of advantage in such cases to install a new belt. V-belts contaminated with oil or grease for any length of time are usually no longer serviceable and must be replaced. When correctly adjusted, the V-belt can be deflected by 15-20 mm (5/8 - 3/4 in.) under slight thumb pressure applied midway between both belt pulleys. The belt should not show any signs of wear such as frayed edges or split flanks.

80

1.5.2 Adjusting V-Belt Tension

Note New V-belt will stretch after a short time of use so that they no longer have the proper tension after 50 - 100 km (30-60 miles). For this reason it is absolutely necessary to recheck the belt tension of new belts within a short period subsequent to the installation. Attempts to remove the V-belt by means of a screwdriver, without loosening the generator pulley, will result in damaged V-belt and pulley.

• 1. Remove generator pulley retaining nut (36 mm wrench); to lock the pulley in place during this procedure, insert a square-edged screwdriver into the recess in the inner edged of the pulley and brace, it .against the top bolt protruding from the generator housing.

• 2. Remove outer pulley half.

81

Adjusting V-Belt Tension

• 3. Arrange spacers between pulley halves as needed. The belt tension should be so adjusted, by adding or removing spacers between the two pulley halves, that the belt will yield by about 15-20 mm (5/8 - 3/4in) under light thumb pressure. Removal o|.ipacers increases the belt tension, addition of spacers decreases the tension (see Fig. 72). If the belt has streched or worn to such extent that only one spacer remains between the pulleys at correct belt tension, it should be replaced since the condition will result in insufficient cooling due to decreased impeller speeds. In addition, it should be noted that the belt does not ride at the pulley root, that is, on the pulley spacers.

• 4. Mount outer pulley half. • 5. Spacers not inserted between the two pulley halves should be placed

onto the shaft between the outer pulley half and the nut so that all spacers remain on the pulley hub.

• 6. Tighten pulley retaining nut. Loose pulley halves will quickly become defective in their seats and also cause a rapid V-belt wear. Damaged pulley halves must be replaced.

82

1.6 DESCRIPTION OF THE 912 (356 B/T6) HEATING SYSTEM

1.6.1 Functional View of the Heating System (Germany and Sweden)

Due to varying laws in force, it is necessary to equip The Type 912 cars with two different heating systems. Cars manufactured for sale in Germany and Sweden are equipped with a modified heating system known as 356 B/T6 whereas all other Type 912 export cars continue to be equipped with the well-proven and reliable Export-type heating system. The difference between the two systems is that in the 356 B/T6 system the air required for heating is drawn from the air blower housing and ducted to the passenger compartment through the heat exchangers, without passing through the engine cooling cycle. In the Export-type heating system the cold air performs its engine cooling function and, already preheated, is ducted into the heat exchanger and on to the passenger compartment. The desired effectiveness of both heaters is achieved through the use of appropriately designed heat exchangers.

83

1.6.2 Functional Description

The entire fresh air mass enters through slots in the engine compartment lid (1), being drawn in by the cooling air blower. Part of the fresh . air mass required for heating the passenger compartment is diverted from the cooling air blower (2) into a separate duct (3), The fresh air (outside air) flows from the supply duct through the two heat exchangers (4) at the engine. The heat exchangers consist of sheet- metal jackets which enclose the exhaust pipes (5). All detachable and welded joints of the exhaust system (6) are located outside the heat exchangers. The entire engine exhaust system as well as most part of the engine, such as the crankcase and cylinders, is located in the free-air stream beneath the rear section of the car. The heating air flows from both heat exchangers' through connecting hoses (7), air gates (8), guide ducts (9), and silencers (10) which are situated within the longitudinal chassis support members, to heat outlets arranged in pairs.

Heat outlets are provided as follows: For defrosting the windshield (11) and the rear window (12) by way of defroster nozzles. For the forward leg area (pedal area) by way of sliding gates (13) located alongside the longitudinal chassis supports next to both seats. The air gates (8) are so designed as to permit a continuous flow of air through the heat exchangers (over the exhaust pipes) regardless whether the heat is turned on or off. In addition, outside air may be let in through the ventilating system (14) in front of the windshield independently of the cars heating system. Hot air for preheating the carburetors is taken from the hot air stream.

84

1.6.3 Operating description:

Heater Control

The heat is controlled through a control lever (15) located in front of the gearshift lever. With the lever moved back, the heater is open, and with the lever moved forward, the heater is closed. Through the lever action, air gate flaps are moved in the air gate assembly (8) by way of a cable connection. Should the cable break, the two flaps shut automatically and the hot air is permitted to flow outside.

85

Located in the forward leg area, along the right and left sides adjacent to the front seats, are sliding gates (13) with which it is possible to regulate the flow of hot air to the leg area. When the slider is moved forward, the flow of air stops although in that case the entire warm air supply enters the passenger compartment through the defroster nozzles (11 and 12).

87

1.6.4 Bottom View of Vehicle

Bottom view of Vehicle. Heater Type 356b/T6.

1. Transmission filler plug 2. Transmission drain plug 3. Transmission 4. Clutch control lever 5. Engine drain plug 6. Oil strainer cover 7. Engine crankcase 8. Exhaust muffler 9. Forward power train carrier 10. Suspension control arm 11. Heating air control gate 12. Axle shaft 13. Shockabsorber 14. Heat exchanger 15. Tail pipe

88

1.6.5 Description of the Export - Type Heating System

1.6.6 Functional View of the Heating System

Functional Description The entire fresh air mass enters through slots in the engine compartment lid (1). being drawn in by the cooling air blower (2). The air blower forces the air over the cylinders (3) where it is preheated, and on to the lower air ducts. When the heater is shut off, the air flows directly outside. When the heater is turned on (control lever -15- moved back), the air flows through a heat jacket into connecting hoses (8), dueling pipes (9), and silencers (10) into the passenger compartment. The following hot air outlet pairs are provided: Windshield defrosting nozzles (11) Rear window defrosting nozzles (12) Leg area outlets through sliding gates (13) located adjacent to the front seats. In addition, independently of the car's heating system, ventilating outside air may be let in through the ventilating system (14) in front of the windshield. When the heater is on, warm air enters the engine compartment through outlets (5). This warm air prevents carburetor icing and undercooling of the engine. The flow of air into the engine compartment is controlled by a thermostat. Operating Description: See description of 356B/T6 heater

Bottom View Of Vehicle - Export - type Heater. ...More



89

1.6.7 Bottom View of Vehicle - Export Type Heater

1. Transmission drain plug 2. Transmission filler plug 3. Transmission 4. Clutch control lever 5. Engine drain plug 6. Oil Strainer cover 7. Engine crankcase 8. Exhaust muffler 9. Forward power train carrier 10. Suspension control arm 11. Axle shaft 12. Heating air control gate 13. Shockabsorber 14. Lower air duct for heater 15. Tail pipe

90

1.7 REMOVING AND INSTALLING EXHAUST MUFFLER

This procedure refers specifically to the German/Swedish version of the heating system.

1.7.1 Remove Clamps from Heat Exchangers

• 1. Remove both supports for engine rear shield. • 2. Loosen the four exhaust pipe clamps behind the heat exchangers.

91

1.7.2 Remove Muffler

• 3. Loosen and remove supporting straps in the center of the muffler. • 4. Pull muffler back to remove, loosening stuck pipe connections through

light tapping with a rubber mallet.

1.7.3 Installation

Installation is accomplished in reversed order, of the above by noting the following points:

• 1. Inspect muffler and exhaust pipes prior to installation for leaks or possible damage.

• 2. Straighten flattened or bent pipes. The welded joint between the muffler and the rear exhaust pipe is particularly exposed to collision damage. Exhaust gases escaping through any cracks at this point can enter the engine compartment and with the heater on, the car's interior.

• 3. Use new gaskets. • 4. Ensure that a good gas-seal is achieved at the front pipe connecting

points. If the mating flanges are not straight, straighten prior to installation.

• 5. With the engine installed, the exhaust muffler must not touch the body,

92

1.8 ENGINE LUBRICATION SYSTEM

Oil Circuit Diagrams

1.8.1 Oil Circuit in Cold Engine

1. Rocker arm 2. Pushrod 3. Piston 4. Valve lifter 5. Oil suction tube 6. Pressure relief valve 7. Bypass valve 8. Camshaft 9. Crankshaft 10. Oil pump 11. Counter-pressure line 12. Oil line to Bearing 4 13. Oil temperature sensor 14. Oil pressure switch 15. Oil cooler (repositioned back in sketch for better view) 16. Bypass oil filter

93

1.8.2 Oil Circuit at Operating Temperatures

Description of the Oil Circuit

The oil pump (10) draws cold oil from the crankcase sump and forces it to the bypass valve (7) which opens at a pressure of approx. 1.3 atm (19 psi), i. e., the piston of the bypass valve is forced down, thus clearing a passage which leads directly to the lubricating points by bypassing the oil cooler (15). The pressure relief valve (6) in the crankcase opens when the pressure rises above approx. 2. 9 atm (42 psi) and dumps the oil excess into the crankcase oil sump. As soon as the oil galleries have filled with oil and the oil pressure has stabilized, a pressure rise equivalent to the pressure in the rest of the system also occurs in the counter-pressure line (11) and under the bypass valve (7). thus equalling the pressure exerted upon the bypass valve from the side of the pump (10). The pressure relief valve (6) limits the oil pressure in the system to 3 atm (44 psi). The mechanical spring in the bypass valve exerts a pressure equivalent to approx. 1.3 atm (19 psi). Since equal oil pressure now prevails at both ends of the bypass valve, the mechanical spring is able to expand and, so, move the bypass valve up. As the bypass valve (7) moves up, it'blocks the direct passage and causes the oil to flow through the oil cooler before reaching the lubricating points

94

Oil Strainer

1.8.3 Removing Oil Strainer

• 1. Remove hex nuts from oil strainer cover. • 2. Remove oil strainer cover. • 3. Remove oil strainer and gaskets.

1. Oil drain plug 2. Gasket 3. Oil strainer 4. Gasket 5. Oil strainer cover with magnetic filtering element

95

Install Installation is accomplished in reversed order of the above by noting the following points:

1. Check oil suction tube for proper positioning. 2. Clean oil strainer and remove gasket remnants. 3. Use new gaskets on both sides of the oil strainer. 4. Insert oil strainer making sure that the orifice in the strainer has a close

fit around the oil suction tube. 5. Remove gasket remnants from the oil strainer cover. Straighten the

cover if it is warped or bent, otherwise a good oil seal cannot be expected.

6. Clean magnetic filtering element. 7. Do not over tighten the hex retaining nuts, especially when using thicker

gaskets, since this may warp the cover.

96

1.8.4 Magnetic Oil Filtering

A magnetic oil filtering element has been included in the oil strainer cover to provide for a better filtering of the oil. The element is situated in the center of the oil strainer cover with the oil suction tube located within it. The oil first passes through the oil screen and then flows through the magnetic filtering element.

1. Crankcase 2. Oil strainer 3. Magnetic filter 4. Oil suction tube 5. Stud 6. Oil strainer cover 7. Disc 8. Rivet 9. Gasket

97

1.8.5 Pressure Relief Valve

Special Tools: P 74 Socket attachment

General The pressure relief valve is located in the crankcase and governs engine oil pressure. When encountering malfunctions in the engine lubrication system, and always in cases of leaks in the oil cooler, check the pressure relief valve for proper functioning. The bypass circuit valve is located in the timing gear cover and ensures immediate lubrication of engine bearings and other points when the engine is started.

98

1.8.6 Bypass Valve

The purpose of the bypass valve in the timing gear cover is to provide instant lubrication for points in the engine, by bypassing the oil cooler, when the engine is started.

1. Oil gallery to oil cooler 2. Oil gallery from oil pump 3. Oil gallery to lubricating points by bypassing the oil cooler 4. Opening for counter-pressure oil line

99

1.8.7 Bypass Valve at Start Up

When the engine is not running, the valve (plunger) closes the passage to the lubricating points. As soon as the engine begins to run, the oil pump sucks oil from the oil sump in the crankcase and forces it to the bypass valve. The bypass valve is then forced down, under the pressure of the oil, and opens the oil gallery to the lubricating points by bypassing the oil cooler.

100

1.8.8 Bypass Valve When Running

As soon as the oil pressure has built up, some of the oil flows through the counter-pressure line to the cavity under the valve plunger equally counteracting the pressure exerted by the oil from above, permitting the mechanical spring to expand and, thus, push the valve plunger up and close the oil gallery of the direct lubricating circuit. This forces the oil to flow through the oil cooler before it can reach the lubrication points within the engine.

101

1.8.9 Removal Cap Screw

1. Remove cap screw with tool P 74. 2. Withdraw spring and valve plunger; if plunger is stuck, it can be

removed with an M 10 thread tap.

102

1.8.10 Withdraw Spring and Plunger

2. Withdraw spring and valve plunger; if plunger is stuck, it can be removed with an M 10 thread tap.

Installation Installation is accomplished in reversed order of the above by noting the following points:

1. Inspect valve plunger and plunger bore in housing for traces of seizure (scratches, etc.). Carefully smoothen the surfaces, replace if necessary.

2. Check mechanical spring 3. Pressure Relief Valve and Bypass Valve Spring 4. Free length............ 66 mm (2.6in) 5. Wire diameter......... 1.4 mm (.055in) 6. Tension at 49 mm(1.93in).....4.7 kp (10.3 lbs) +/- 7%

7. Install new gasket washer. 8. Insert the piston so that its hollow end faces towards the cap screw. 9. To prevent scratching the bore in the housing, make sure that the spring

end does not ride in the plunger bore in housing.

103

1.8.11 Remove Oil Cooler

• 1. Remove air blower housing. • 2. Unscrew oil cooler retaining nuts with a box wrench. ..

104

Remove Oil Cooler

• 3. Remove oil cooler and gaskets.


1. Check oil cooler for leaks and proper tightness of retaining nuts (test pressure is 10 atm-147 psi).

2. If oil cooler is leaking, check pressure relief valve. 3. Use new gaskets.

105

Oil Pump

1.8.12 Remove Oil Pump

1. Remove engine rear shield and intermediate shield between the air ducts.

2. Remove crankshaft pulley. 3. Remove crankshaft pulleys shield, 4. Remove oil pump cover. 5. Remove oil pump gears.

106

Installation Follow reversed order

1. Inspect oil pump housing, especially gear seating areas, for wear. Wear within the housing will result in decreased oil pressure.

2. Inspect pump gears for wear. Gear flank clearance should be O.03 - O.O5 mm (.001 - .003in.). Axial play of gears in the housing, with gasket but without preload, is 0.035 - O.10 mm (.0014 - 0039in.). Wear limit 0.20 mm (. 0079in).

3. Check shaft of driven gear for firm seating in the housing. 4. Check sealing surface for oil pump cover (a t crankcase) for cleanliness. 5. Place a straight edge across the face of the pump gears. Using a feeler

gauge, measure clearance between the cover mounting flange in housing and face of gears, which should be 0.06- 0.l28 mm (. 0024 - .0050in).

6. Use a new,- genuine gasket (0. 20mm = . OO8in) without applying gasket paste. Gasket thickness in excess of specification will result in decreased oil pressure.

107

Bypass Oil Filter Cartridge

1.8.13 Changing Bypass Oil Filter

Bypass oil filter cartridges used in Porsche cars cannot be cleaned and have to be replaced when contaminated (normal replacement after every 10,000 km or 6,000 miles).

1. Unscrew filter cover retaining bolt. 2. Withdraw filter cover. 3. Withdraw filter cartridge with a slight turn. 4. Remove oil from filter housing (use a suction pump). 5. Clean filter housing interior (do not use shredded rags). 6. Insert new cartridge by turning it slightly. 7. Insert new gasket into housing cover, properly position the cover on the

housing. depress, and tighten securely. 8. Check engine oil level. 9. Allow engine to idle for a few moments. 10. Check for oil leaks in filter housing body and oil line connections. 11. Recheck engine oil level. 12. Replenish engine oil to the top mark on the oil dipstick (use

premium. grade HD oil).

108

1.9 HEADS

Remove and Install Rocker Arm Carrier

1.9.1 Removal Rocker Arm Carrier

• 1. Remove rocker box cover. • 2. Remove the 7 hex nuts (SW 13) from the rocker arm shafts.

109

1.9.2 Remove rocker arm shafts

• 3. Withdraw rocker arm shafts with rocker arms, springs, washers and spacers.

• 4. Remove the three rocker arm carrier retaining bolts (SW 15 mm) and withdraw carrier.

110

1.9.3 Rocker Arm Installation

Installation is accomplished in reversed order of the above by noting the following points:

1. Inspect retaining bolts for defects. Coat threads and base of bolt heads with graphite oil. Use new spring washers,

2. Tighten retaining bolts to 5 mkp (36 lbs/ft).

111

1.9.4 Tighten the Rocker Arm Shaft Nuts

• 3. Tighten the 7 rocker arm shaft retaining nuts (SW 13) to 2,5 mkp (18 Ibs/ft).

• 4. Adjust valve clearance. Reoil shafts and rocker arms, install rocker box cover.

112

1.9.5 Disassembling and Reassembling Rocker Arm Carrier

Disassembly

1. Remove the 7 hex nuts (SW 13) from the rocker arm shafts.

• 2. Withdraw rocker arm shafts with rocker arms, springs, washers, and spacers.

• 3. Remove valve adjusting screws.

Reassembly Reassemble the rocker arm carrier in reversed order of the above by noting the following points:

• 1. Inspect rocker arm shafts and rocker arms for defects. Replace parts showing traces of wear or damage.

• 2. Inspect valve adjusting screws for defects. Replace screws which have strained threads or damaged ball joint sockets.

• 3. Check adjusting screws and rocker arms for unobstructed oil flow. • 4. Arrange the spacers and / or thrust washers in such way that the

rocker arms strike the valve shafts approximately in the center of the shaft butt, and that the pushrods do not come in contact with the pushrod tubes.

• 5. Make certain that the washers, springs, and spacers are properly arranged.

113

1.9.6 Remove Cylinder Head

Special Tools

• VW 157 Allen wrench adapter • VW 118 Torque wrench

Removal This section assumes the engine is removed.

1. Remove lower air duct, side shield, cylinder shrouds, intake duct and carburetor.

114

2. Remove rocker box cover and unbolt rocker arm carrier.

3. Remove cylinder head retaining nuts with A Allen wrench adapter (the 8 A Allen nuts are shown above and below the valve stems in the illustration above); remove washers located between the nuts and cylinder head.

4. Withdraw cylinder head.


• 1. No gasket is used between the cylinder head and cylinders. • 2. Insert push rod cover tubes. To ensure proper sealing at the tube

ends between crankcase and cylinder head. the tubes must have the required length at assembly, that is, used tubes must be stretched at the bellows. The stretching should be accomplished with care so as to prevent possible cracking of the metal.

115

1.9.7 Position Cylinder Deflectors

• 3. When installing the cylinder head make sure that the new a-rings at the cover tube ends are properly seated; position the tubes weld seams up.

o a) Sealing points in crankcase. o b) Sealing points in cylinder head.

• 4. The cover tube O-rings are trapezoidal in cross-section. • 5. Prior to installation, lubricate 0 -rings used under the cylinder head

nuts located within the rocker box. • 6. O-rings should not be coated with gasket compound. • 7. Ensure proper positioning of cylinder deflector baffles (compare profile

of recess for cap nut and one for hex bolt).

117

1.9.8 Torque the Head Bolts

• 8. Place 1 washer under each cylinder head nut situated outside the rocker box.

• 9. Coat cylinder head nuts with graphite paste tighten lightly. then torque to 1 mkp (7. 2 lbs/ ft) in sequence shown in the illustration.

• 10. Torque cylinder head nuts to 3 mkp (21.7 lbs/ft) in sequence shown in the illustra tion.

•

118

1.9.9 Install Pushrods

• 11. Pump oil into pushrods until it comes through at other end, and insert into pushrod cover tubes so that one end seats in the valve lifter.

119

1.9.10 Install Rocker Arms

• 12. Install rocker arm carrier, torque retaining bolts to 2.5 mkp (18.1 lbs/ft).

• 13. Install rocker arms. • 14. Torque rocker arm shaft retaining nuts (SW 13 mm) to 2.5 mkp (18.

1Ibs/ft).

120

1.10 VALVES

1.10.1 Adjust Valves

• 15. Adjust valve clearance. • 16. Mount rocker box cover.

Note

When installing the cylinder head make absolutely sure that the cylinders are properly seated in the cylinder head. If a misaligned cylinder head is tightened, it will most likely warp to the extent of being no longer useable.

121

1.10.2 Removing and Installing Valve Springs

Special Tool Use special tool P7 for removing and installing valve springs.

Checking valve springs:

Free length 47 mm (1,85in)

Wire diameter 4.5 mm (. 177in)

Spring tension with spring compressed to 41 mm (1. 61in)

36kp(79, 3lbs) +/- 5kp(3, 321bs)

Spring tension with spring compressed to 30.15 mm (1.19in)

97kp( 213, 21bs)+/- 2. 5k p( 5. 51lbs)

Spring tension variations up to 50% are permissible in used springs. All valve springs used in one engine must be of equal free length since the length affects springing characteristics.

Checking Installed Length

Note: Intake and exhaust valve springs are of the same length. The installed spring length is changed or adjusted through the addition or removal of spacers located under the springs.

Important: The valve springs must always rest on the steel washer and never on the spacers since the spring could damage the spacers.

1. Install- special tool P 10 with the respective spring retainer and both valve keepers.

2. Determine the indicated value and correct it, if necessary. by adding or removing spacers.

3. Install valve springs so that the closely wound coils rest on the 1,5 mm thick washer (see note, above).

Installed length of valve springs is: Intake = 41,0 mm (1.61in) Exhaust = 40,5 mm (1.59in)

Note: Valve springs made by various manufacturers are supplied under the same spare part number. However, all springs (progressive or linear coils) may be paired in one engine.

122

1.10.3 Valve Spring

Note: Intake and exhaust valve springs are of the same length. The installed spring length is changed or adjusted through the addition or removal of spacers located under the springs.

Important: The valve springs must always rest on the steel washer and never on the spacers since the spring could damage the spacers.

1. Install- special tool P 10 with the respective spring retainer and both valve keepers.

2. Determine the indicated value and correct it, if necessary. by adding or removing spacers.

3. Install valve springs so that the closely wound coils rest on the 1,5 mm thick washer (see note, above).

Note: Valve springs made by various manufacturers are supplied under the same spare part number. However, all springs (progressive or linear coils) may be paired in one engine.

a = Installed length b = Steel washer c = Spacers Installed length of valve springs is: Intake = 41,0 mm (1.61in) Exhaust = 40,5 mm (1.59in)

123

1.10.3 Checking Valve Guides for Wear

Special Tools: P 21b Valve guide plug gauge See: Replacing of valve guides see 35 EN.

Clearance between valve guide bore and valve stem is: Intake = 0.035 - 0.060 mm ( 0.0014in to 0.0024in) Exhaust = 0.055 - 0.080 tnm (0.0022in to 0.0031in)

Valve guide bores should be measured with a valve guide plug gauge of 10 mm diameter (.394in). When installing the sealing caps, it should be noted that first the valve is pushed into the valve guide and then the sealing cap pulled over the valve guide until the base of the cap comes to rest against the valve guide.

124

1.10.4 Checking and Reconditioning Valve Seats

Special Tools

• P 11 Valve seat cutter handle with 10 mm dia. cutter guide • P 12 Eight-piece valve seat cutter set.

Checking

1. Check valve guides for firm seating in the cylinder head. 2. Check valve seating using machinists blue. 3. Inspect valve seat surface. If the valve does not seat on the whole seat

surface, lightly rework the seat with a cutter. 4. Valve seating may be checked with the valves installed in the cylinder

head by pouring some gasoline into the respective port.

Check the Valve Seats

Valve seat width Intake 1.25 +/- 0.15 mm (0.050 +/- 0.006 in.) Exhaust 1.55 +/- O. 15 mm (0.061 +/- 0.006 in.).

Valve seats showing traces of wear or pitting may be refaced providing that the permissible width of the 45 deg. seat can be maintained, and the 25 deg. bevel in the outer circumference does not exceed the outer diameter of the valve seat insert. If this is not possible, the cylinder head must be replaced. It is not p~sible to replace the yalve seat inserts with the equipment at hand in normal workshops.

125

45 degree Cut

1. 45 deg seat cut: The 45 deg cut must be performed with particular care to produce a smooth surface free of chatter marks. It is very important to apply pressure from directly above. Removal of base metal must be held at a minimum so as not to render the valve seat insert prematurely unusable. The cutting procedure should be discontinued as soon as the cutter has cleaned the entire seat area,

75 Degree Cut

2. 75 deg bevel cut: Lightly bevel the lower edge of the valve seat using the 75 deg. cutter.

126

25 Degree Cut

3. 25 deg bevel cut: Using the 25 deg. cutter, bevel the upper edge of the seat until the specified seat width is obtained.

127

Refacing Valves

Valves showing face wear of a degree that cannot be corrected through lapping, may be dressed on a valve refacing machine. Refacing of the valves must be accomplished with appropriate care. Particular attention should be devoted to the fact that only so much of the base metal is taken off as is required to produce a clean valve face. The valve stem must, in no way, show traces of contact with the dressing wheel; valves with stems touched by the dressing wheel must not be installed. Valve dimensions

Intake Exhaust

A 37. 9 - 38. 1 mm (1.492 - 1.500 in.) 33. 9 - 34.1 mm (1.334 - 1.342 in.)

B 117.9 mm (4.630 in.) 128.5 mm (5.060 in.)

C 9.98 - 9.99 mm (.3929 - .3933 in.) 9.96 - 9.97 mm (.3921 - .3925 in.)

b 1.7 - 2.3 mm (.067 - .091 in. ) 2.0 - 2.3 mm (.079 - .091 in.)

128

1.10.5 Seating, Inspecting and Testing Valves

Seating Valves

Special Tools: P 9 Suction cup, for turning valve The following points should be observed when seating (lapping) valves:

Lapping The following points should be observed when seating (lapping) valves:

1. Seat valve with the P 9 suction cup. 2. Use fine-grain grinding compound to prevent roughness or "grooving". 3. Upon completion of lapping, fully remove all grinding compound

remnants.

Note: The grinding compound is water-soluble and should not be exposed to oil or grease. A special effort should be made to thoroughly clean and flush with water all involved component parts of the engine, including the valve guide bores, and then to dry and oil these prior to reassembly.

Inspecting Valves

1. Clean valves from carbon deposits. 2. Inspect valve face for wear or pitting. If necessary. reface on dressing

machine. When refacing the valves, make certain that --especially in the case of the thermally higher stressed exhaust valves- - the dimension b (see Fig. 123) is not exceeded.

3. Valve stems showing excessive wear (ridge formation) must be replaced. 4. Valves with warped stems, traces of seizure, or damaged valve keeper

seats must be replacad. Valve stems cannot be reground or straightened for any reason.

Testing Installed Valves For Leakage

Installed valves may be tested for leakage by pouring some gasoline into the respective port. Properly seated valves will not permit gasoline to pass through.

129

1.10.6 Adjusting Valve Clearance

Valve clearance (cold) is: Intake 0.10 mm (0.004 in) Exhaust 0.15 mm (0.006 in)

General: Excessive clearance causes valve noise and decreased power. Insufficient clearance results in decreased power, valve overheating or burning, and carburetor flashback which may cause a carburetor fire. We therefore recommend that the valves be adjusted in a reputable shop. The valves should be adjusted when the egine is cold. The best sequence to follow is Cyl. 1, 2, 3, and 4 while rotating the crankshaft counterclockwise. Prior to adjusting, position the piston on top dead center (TDC) on compression stroke since both valves are closed at that point. If adjustment begins with Cyl. 1, turn crankshaft counterclockwise until both valves are closed and the "OT" (TDC) mark on the crankshaft pulley is lined up with the mark on the crankcase.

Adjusting:

• 1. Remove both rocker box covers (engine cold). • 2. Remove distributor cap.

130

Adjusting Valve Clearance

• 1. Remove both rocker box covers (engine cold). • 2. Remove distributor cap. • 3. Turn crankshaft counterclockwise- -using a box wrench on the

crankshaft pulley, if necessary-- until the "OT"-mark on the pulley has lined up with the mark on the crankcase. At this point, the distributor rotor will be pointing towards a notch machined into the distributor housing.

131

Adjusting Valves

Valve clearance (cold) is: Intake 0.10 mm (0.004 in) Exhaust 0.15 mm (0.006 in)

• 4. Check valve clearance at Cyl. 1. • 5. Loosen lock nut on adjusting screw. • 6. Adjusting clearance by turning the screw while simultaneously

checking the clearance with a feeler gauge. • 7. Hold adjusting screw in position when tigtening the lock nut. • 8. Recheck clearance.

132

1.10.7 Checking Valve Timing and Clearance

Normally the valve clearance should be checked or adjusted when the engine is cold at an outside air temperature of approx. 20 deg C (68 deg F). The valve clearance is as follows:

Intake valves 0.10 mm (0.004 in) Exhaust valves 0.15 mm (0.006 in)

Valve clearance should be checked a t regular intervals and appropriate care. The following malfunctions can be caused by wrong valve adjustment:

Insufficient clearance: Burnt or pitted valves and seats. Warped valves. Unevenly running engine. Valve timing off

Excessive clearance: Valve noise Increased wear in valve components Unevenly running engine Valve timing off

Proper valve adjustment results in a well running engine only when the valves are seating well, the valve guides are not worn, and the valve stem ends are not pounded in or otherwise worn.

Valve timing points:

Intake opens before TDC 17 deg

Intake closes after BDC 53 deg

Exhaust opens before BDC 50 deg

Exhaust closes after TDC 14 deg

Note :

The above timing points are established with 1.00 mm valve clearance in cold engine. When valve timing has been checked, reset valve clearance to normal specifications. Lapped or refaced valves and seats seat faster than normal. For this reason, set valves with an additional 0.15 mm (0.006 in) clearance over the specified value for a test run of at least one-half hour. When the test run has been completed, or before testing engine performance, readjust valve clearance to normal values.

133

1.10.8 Removing and installing Valve Guides

Punch out the Valve Guides

1. Drill valve guides with a 12 mm (0.427 in) drill to loosen in their seats. 2. If a heating oven is available. the guides need not be drilled but, instead, the head heated to approx. 180 deg C (356 deg F), 3. Using a punch of proper size (see illustration), drive the valve guides out towards the combustion chamber.

Installation The valve guide receiving bores in the cylinder head will have widened somewhat during the removal Consequently. oversized valve guides will have to be used and properly fitted into the head. 1. Precisely measure the valve guide receiving bores in the head. 2. Machine the oversize valve guides on a lathe to bring to outside diameter matching that of the bore in the head. The required preload for the in take and exhaust valve guides is 0.041 - 0.06 mm (0.0016 - 0.0024 in). 3. Press the valve guides into the cylinder head from the rocker arm side. Use tallow for lubrication. 4. Ream the guides with a broach reamer or a precision drill to a diameter of 10 mm E7. If necessary, the valve guides may be reamed with a conventional reamer.

134

1.10.9 Removing and installing Valve Seat Inserts:

1. Using a portable electric grinder, grind through a valve seat insert so that it loosens in its seat. 2. Drive the old seat insert out. 3. Precisely measure the seat receiving bore in the head. 4. Machine the oversize valve seat inserts on a lathe to bring to outside diameter matching that of the bore in the head. The required preload is as follows: Intake valve insert: 0.15 - 0.19 mm (0.006 to 0.0075 in) Exhaust valve insert: 0.10 - 0.15 mm (0.004 to 0.006 in)

5. Heat cylinder head to approx. 200 deg C (392 deg F). 6. Using an appropriate driver, drive the valve seat insert into place. 7. Allow the cylinder head to slowly cool to room temperature.

Table of Dimensions for Valve Guide Installation (l mm = 0.03937 in)

Valve Guide Size

Valve Guide Outside Dia.

Diameter of Receiving Bore in Cylinder Head

Standard 14,048 - 14,059 mm 14,000 - 14, 008 mm

1st oversize 14, 248 -14,259 mm 14,200 - 14,208 mm

2nd oversize 14,448 - 14,459 mm 14,400 - 14,408 mm

Table of Dimensions for Valve Seat Insert Installation

Insert Size Insert Outside Diameter

Diameter of Receiving Bore in Cylinder Head

Standard (intake) 41,182 - 41,198 mm

41,000 - 41,025 mm

1st oversize (intake)

41,502 - 41,518 mm

41,328 - 41,352 mm

Standard (exhaust)

37,120 - 37,140 mm

36,990 - 37.020 mm

1st oversize (exhaust)

37,680 - 37,700 mm

37,550 - 37.580 mm

135

1.11 CYLINDERS

1.11.1 Reconditioning and Exchange of Cylinder Heads

General

Cylinder heads with worn valve guides, valve seats. or spark plug inserts may be sent to the factory for reconditioning. When the cylinder heads are being reconditioned, the combustion chamber displacement is measured and so indicated in cubic centimeters. Make sure that cylinder heads used in one engine have the same combustion chamber displacement (permissible deviation is +/- 1 cc).

1.11.2 Check Cylinder Head Displacement

Reworked cylinder heads must be checked for combustion chamber displacement and the appropriate value stamped into the head. Should it be not possible to send the cylinder heads back to the factory for overhaul, the job may be performed locally providing that the required equipment is at hand.

136

1.11.3 Removing and Installing Cylinders

Special Tool P 8a Piston ring compressor, 82.5 mm diameter.

Removal 1. Remove rocker arms and rocker arm carrier, Remove valve pushrods and mark for reassembly. 2. Remove cylinder head and push rod cover tubes (25 En). 3. Withdraw cylinders, mark 1 through 4 as appropriate.

137

Cylinder Installation

Installation is accomplished in reversed order of the above by noting the following points: 1. Check cylinders for wear, if necessary replace together with pistons of same size group. 2. The cylinder seat in crankcase and cylinder head must be clean at time of installation since dirt particles lead to cylinder distortion. Using a straight edge, check cylinder seats in crankcase for linear alignment of seating surfaces in relation to each other and, upon insertion of cylinders into crankcase, check alignment across the top of cylinders. 3. Use new gasket rings a t base of cylinders. 4. Check and oil pistons and piston rings. Ensure that piston rings are installed in appropriate locations (check "TOP" markings). 5. Stagger piston ring gaps 12 deg. apart with oil control ring gap facing up, compress rings wi th piston ring compressor. 6. Lightly oil cylinder bores and push onto pistons, Visually check the required clearance between the cylinder stud bores and studs, The studs must not touch the cooling fins. Clearance can be determined by turning the cylinders in their bases, If necessary, straighten studs. 7. Install pushrod cover tubes. Do not fail to install deflector baffles and supporting springs. 8. Tighten cylinder head nuts to 3 mkp (21. 7 lbs/ft) by following proper sequence.

138

1.11.4 Inspecting Cylinders

Special Tools: P 13c Cylinder gauge setting ring

Standard Size (Note: 1 mm = 0,03937 in)

Group Cylinder Diameter Piston Diameter

-1 82,485 - 82,494 82,47

0 82,495 - 82,504 82,48

+1 82,505 - 82,514 82,49

1st Oversize

Group Cylinder Diameter Piston Diameter

-1 KD 1 82,985 - 82,994 82,97

0 KD 1 82,995 - 83,004 82,98

+1 KD 1 83,005 - 83,014 82,99

The above tables show which piston and cylinder size groups can be paired. Wear limit is a clearance of 0,2 mm ( 0.008 in) between piston and cylinder. Exact piston to cylinder clearance can be determined only by measuring each component separately. Measure cylinders at a point approximately 15 mm (3/4 in) below the cylinder top using a bore micrometer with setting ring P 13c. Replace cylinders which are worn close to the permissible wear limit.

139

1.11.5 Cylinder Marking

All cylinders are marked at the base to indicate the bore diameter group, such as "0", or reconditioned units by "+ 1 KD I" etc. The piston tops bear appropriate size values (+1 KD 1, etc),

The piston to cylinder clearance when new is 0.02 mm (0.0008 in), the wear limit is 0.2 mm (0.008 in). Cylinders worn close to the wear limit should be replaced together with pistons; use cylinder / piston replacement sets falling into the appropriate size group. Piston/ cylinder sets installed in one engine may not differ by more than four size groups.

Note: The Biral cylinders are available in four height groups; cylinder height is the distance between the cylinder seating flanges at the crankcase and the cylinder head. Cylinders installed under one cylinder head must be of same height and bear same identifying symbols at the cylinder base. The identifying symbol is a triangle inside which the number 5, 6, 7, or 8 is stamped, depending on the particular size group.

140

1.11.6 Removing and Installing Pistons

Special Tools: P 1a Electric piston heater P 2 Piston pin mandrel

General:

Install the Piston with the Arrow toward the Flywheel

The piston pins are arranged in the pistons off the center and it is, therefore, important to correctly install the pistons in the engine. The piston top bears an arrow mark. When installed, the piston must be so oriented that the arrow points in the direction of vehicle travel, i. e., towards the flywheel.

141

Off Center Piston Pin

Owing to the off-centered piston pin, the connecting rod shifts its direction of attack, and so does the piston its tangential angle in relation to the cylinder wall prior to reaching the top dead center (TDC). Since in this position the combustion has not yet begun, the prevailing side forces are still small. which permits the piston to shift onto the opposite cylinder wall softly rather than with a slamming impact. As a result, piston slap noise occuring at time of the pressure point shift is kept at a minimum, especially when the piston to cylinder wall clearance is greater than normal.

142

1.11.7 Remove and Mark Cylinders

1. Remove cylinders. 2. Mark pistons to ensure reassembly in original position and location.

http://www.hillmanimages.com/912/manual18.html

143

1.11.8 Heat Pistons

3. Remove piston pin retainers making sure they don't fall into crankcase. 4. Heat pistons to approx 80 deg C (175 deg F) using electric piston heater.

144

1.11.9 Remove Pins and Rings

5. Using the piston pin mandrel, drive piston pins out and remove pistons. 6. Remove piston rings (if necessary) using a piston ring expander. To avoid breaking or bending the piston rings, expane! these as little as possible, keeping rings close to the piston body.

145

1.11.10 Check Proper Size of Rings

1. Connecting rods must be in proper alignment. 2. Clean pistons. Remove carbon deposits from piston top and piston ring grooves without scratching the base metal. Signs of uneven contact or carbon deposits on one side of the piston may indicate poor connecting rod alignment. 3. Check piston rings for proper condition, ring gap, and ring groove clearance. If not as specified, replace piston rings or pistons, as required. 4. Measure pistons. Size designation is stamped into each piston top. Measurements are accomplished as shown in the illustration (perpendicular to piston pin axis). Piston size groups are shown in tables. Piston clearance at installation is 0.02 mm (0.0008 in). If the measurement of the piston and cylinder reveals a clearance approaching the wear limit, the piston and cylinder should be replaced with a set falling into the same size group. If the mating cylinder of a damaged piston does not show traces of wear or damage, it may be possible to replace the piston alone with one falling into the appropriate size (letter) group.

146

1.11.11 Check Ring Fit in Piston

5. Fit compression rings and oil scraper. 6. Check piston ring gap. This is done by inserting the ring into the cylinder and pushing it down, somewhat. with a piston. then measuring gap with a feeler gauge. Applicable to all rings: Ring gap 0.3 - 0.45 mm (0.012 - 0.018 in). Stagger piston ring gaps so that they are approx. 120 deg apart. Piston ring side clearance is specified in the Table of Tolerances and Wear Limits (page E 95). Piston rings must be installed with a ring expander to prevent piston damage or ring breakage. Piston rings must be installed in the piston so that the "TOP" marking on the ring faces up, i. e., towards the piston top.

147

1.11.12 Install Piston Pins

7. Insert piston pin retainer on the flywheel side first. 8. Inspect and install piston pin. The piston pin is held in the piston through interference fit. If the piston pin can be pushed into the cold piston by hand, use a pin of larger diameter. A color code marking inside the piston on the piston pin boss indicates the proper size of the piston pin, as follows:

white - 21. 997 -22. 000 mm blue - 22.000-22,003 mm

Piston pin clearance in the connecting rod bushing is O. 020 - 0.036 mm (0.OOO8 in to 0.0014 in). If the clearance a pproaches the wear limit of 0.050 mm (0.002 in), fit a new piston pin into a new connecting rod bushing. Install the cold, oiled piston pin in the piston which has been heated to 80 deg C (175 deg F) through immersion in hot oil or application of the e1ectric piston heater, in which condition the pin should slide into the piston under light pressure; the pin should be pushed through, to the pin retainer, in one continued move. 9. Install second pin retainer. The pin retainers must fit well in their groove within the piston pin boss.

148

1.11.13 Inspecting Pistons

Piston diameter is indicated by size group stamped into the piston top. The individual size groups are shown in the [html:/912/manual22.html piston size table]. Piston measuring point is shown in Fig. 137. In order to obtain precise measurement values, we recommend the use of a fixed dial gauge which has been preset with gauge blocks. Pistons showing evidence of seizure or wear are no longer serviceable; however, if the mating cylinder is in good condition, the fault can be rectified by installing only a new piston of the appropriate size group or letter designation.

Piston Measuring Points and Identification Conspiculously broad bevel around the piston top perimeter. Two compression rings above the piston pin, one oil scraper below the piston pin. Nominal diameter measuring point shown by arrow [html:/912/912_fig_137 (Fig. 137)].



149

1.11.14 Piston Measuring Points

Piston diameter is indicated by size group stamped into the piston top. The individual size groups are shown in the piston size table. Piston measuring point is shown in Fig. 137. In order to obtain precise measurement values, we recommend the use of a fixed dial gauge which has been preset with gauge blocks. Pistons showing evidence of seizure or wear are no longer serviceable; however, if the mating cylinder is in good condition, the fault can be rectified by installing only a new piston of the appropriate size group or letter designation.


150

1.11.15Piston Size Table

Piston Size Groups

Piston Dia. +/- 0.005 mm Stamped Marking Size Group

82,49 + 1

82,48 0 Standard size

82.47 - 1

82,99 + 1 KD 1

82,98 0 KD 1 1st oversize

82,97 - 1 KD 1

83,49 + 1 KD 2

83,48 0 KD 2 2nd oversize

83.47 - 1 KD 2

Piston Pin Size Groups

Piston Pin Tolerance Category Color Code Spare Part Nr.

0,000 ... - 0.003 mm White 616.103.321.01

0,000 ... + O.003 mm Blue 616.103.321.50

151

1.12 CRANKCASE

Crankcase Disassembling and Reassembling

Special Tools:

• P 44 Hex socket (36 mm) • P 49 Retaining Springs

Disassembly

1.12.1 Crankcase Dissassembly

• 1. Remove oil drain plug. • 2. Remove oil cooler. • 3. Remove flywheel. • 4. Remove oil pressure switch. • 5. Remove oil pressure relief valve.


152

1.12.2 Remove Oil Pump

• 6. Remove oil strainer and magnetic filtering element. • 7. Remove fuel pump insulating flange. • 8. Remove distributor and distributor pinion shaft. • 9. Remove crankshaft pulley and Woodruff key. • 10. Remove pulley shield. • 11. Remove oil pump

http://www.hillmanimages.com/912/manual9.html#hdr16

153

1.12.3 Remove Timing Gear Cover

• 12. Remove generator carrier. • 13. Remove timing gear cover.

154

1.12.4 Separate the Case

• 14. Remove crankcase retaining nuts. • 15. Remove crankcase retaining nuts at camshaft end (flywheel side). • 16. Withdraw right crankcase half using a rubber mallet if necessary. Do

not pry with sharp tools, such as a screw driver, as this could damage the mating surfaces.

• 17. Remove valve lifters. • 18. Withdraw camshaft and crankshaft. • 19. Remove camshaft end cap. • 20. Remove crankshaft oil seal at Bearing 1. • 21. Withdraw Bearing 2 and 3.

155

1.12.5 Not Correct Position of Timing Gears

Reassembly is accomplished in reversed order of the above by noting the following points:

• 1. Inspect crankcase and timing gear cover for cracks or damage. • 2. Using an appropriate solvent, remove sealing compound remnants

from crankcase mating surfaces. • 3. Check mating surfaces for linear alignment and cleanliness. • 4. A ssemble empty crankcase and tighten retaining nuts. Using an

inside micrometer, measure main bearing bores. • 5. If necessary, lightly break the sharp edges from main bearings bores. • 6. Flush oil passages with solvent and blow trough with compressed air. • 7. Check oil suction tube for firm seating and tightness; if necessary,

refasten with P 50a ball end punch. • 8. Check valve lifters and lifter guide bores. • 9. Check firm seating of dowel pins aligning timing gear cover. • 10. Insert main bearing dowel pins. Install main bearing inserts for

Bearing 2 and 3- place the insert half which has the oil passage into the left crankcase half making sure that the passage in the insert lines up with the passage in the crankcase bearing seat; install the other insert halves in the right crankcase half.

• 11. Install crankshaft and camshaft, check for free rotation. • 12. Install thrust washer, crankshaft oil seal and Bearing 1. • 13. Note correct positioning of timing gears. (See Fig. 142).

156

1.12.6 Install Timing Gear Cover

• 14. Install camshaft end plug, seal with gasket compound. • 15. Secure valve lifters with P 49 retaining springs. • 16. Apply a thin, uniform coat of gasket compound to crankcase mating

surfaces, Make absolutely certain that no gasket compound enters oil galleries of crankshaft and camshaft bearings.

• 17. Join crankcase halves. • 18. Install o-rings and beveled washers fitted under cap nuts; position

the washers so that the inside bevel faces the crankcase to accommodate the o-rings, Tighten cap nuts to 4 mkp (29 lbs/ ft),

• 19. Tighten crankcase retaining nuts at camshaft end (flywheel side). • 20. Install timing gear cover. • 21. Tighten remaining crankcase retaining bolts to 3 mkp (21. 7 lbs/ft). • 22. Tighten timing gear cover retaining nuts to 2 mkp (14. 5 lbs/ft). • 23. Install new oil seal at Bearing 4 in timing gear cover, • 24. Turn crankshaft to check for free rotation. • 25. Install fuel pump insulating flange and fuel pump.

157

Distributor Pinion Shaft R/R

1.12.7 Disconnect Distributor

• 1. Remove distributor cap. • 2. Detach connecting wire from distributor. • 3. Remove hex nut which holds distributor base plate. • 4. Withdraw distributor. • 5. Remove fuel pump, insulating flange, gaskets, and actuating plunger

(13 Fu). • 6. Withdraw distributor. pinion shaft by pushing up and turning to the

left through orifice of fuel pump receiving flange. • 7. Withdraw thrust washer from pinion shaft base in crankcase (Caution -

do not drop washer into crankcase interior). • 8. Withdraw spring from pinion shaft.

158

1.12.8 Inspect and Install Pinion Shaft Washer


• 1. Inspect fuel pump cam and shaft pinion for wear. If pinion shows traces of wear, install new pinion shaft as well as distributor drive gear (bronze) on crankshaft.

• 2. Inspect thrust washer at base of pinion shaft for wear, replace if necessary (Caution - do not drop washer into crankcase interior).

159

1.12.9 Install Pinion Shaft

• 3. Position piston in Cylinder 1 on firing point TDC and insert pinion shaft. The coupling slot in the pinion shaft is off center. When instal!ed, the pinion shaft must be so positioned that the slot is directly perpendicular to the longitudinal engine axis with the smaller section of the pinion shaft top facing towards the crankshaft pulley.

160

1.12.10 Insert Spring in Pinion Shaft

• 4. Insert spring into pinion shaft with the help of a welding rod or a thin screwdriver.

• 5. Install distributor. • 6. Connect wire to distributor. • 7. A djust ignition timing. • 8. Mount distributor cap.

161

Removing and Installing Oll Seal at Bearing 4

Special Tools P 73 Installer for oil seal at Bearing 4

Removal

• 1. Remove crankshaft pulley (47 En). • 2. Withdraw Woodruff key. • 3. Deform old oil seal by striking it with hammer and punch through the

recess slot in the seal sea t, withdraw oil seal. • 4. Withdraw oil deflector. • 5. Remove burr, if any, from oil seal seat.

1.12.11 Install Bearing 4 Oil Seal

Fig 148

• 1. Insert oil deflector. • 2. Install oil seal with P 73 installer. • 3. Lubricate oil sealing surface on crankshaft pulley (smoothen if

necessary). • 4. Insert Woodruff key. • 5. Install crankshaft pulley.

162

Bearing 4 R/R

Special Tools

• P 27 a Assembly plate for removing and installing Bearing 4 • P 73 Installer for oil seal at Bearing 4

Removal

1.12.12 Deform Oil Seal

• 1. Remove timing gear cover. • 2. Deform old oil seal by striking it with hammer and punch through

recess slot in seal seat.


163

1.12.13 Pry Oil Seal

• 3. Pry old oil seal out with a screwdriver or similar tool.

164

1.12.14 Heat and Remove Bearing 4

• 4. Withdraw oil deflector. • 5. Remove bearing set screw. • 6. Remove burr. if any. from recess in oil seal seat. • 7. Heat timing gear cover to approx. 60 deg C (140 deg F) and remove

Bearing 4 using punch P 27a of the assembly plate set.

165

1.12.15 Install Oil Seal

• 1. Inspect timing gear cover for absence of damage. • 2. Inspect Bearing 4 seating bore in timing gear cover. • 3. Turn set screw of Bearing 4 until the tip of the screw projects approx.

1 mm into the bearing seating bore in timing gear cover. • 4. Heat timing gear cover to approx. 160 deg C (320 deg F) and install

Bearing 4 using special tool P 27a. • 5. Tighten the bearing set screw; make sure that the screw is not too

long, such as to exert pressure upon the bearing. • 6. Insert oil deflector. • 7. Install oil seal using P 73 installer.

Note: When installing Bearing 4, proceed quickly since the bearing insert will begin to expand immediately upon contact with the hot timing gear cover and may, possibly. bind in the process.

166

1.12.16 Timing Gear Cover R/R

Removal

• 1. Remove generator (5 En). • 2. Remove generator carrier. • 3. Remove distributor and distributor pinion shaft. • 4. Remove fuel pump (13 Fu). • 5. Remove crankshaft pulley (47 En). (See Note, below). • 6. Remove crankshaft pulley shield. • 7. Remove oil pump (21 En). • 8. Remove retaining nuts from timing gear cover. • 9. Remove timing gear cover. • 10. Remove counter-pressure oil line and rubber plugs.

Note: To prevent damaging the oil seal in timing gear cover, remove Woodruff key from crankshaft before wi thdra wing the cover.

Installation

167

1.12.17 Timing Gear Cover O-Rings

• 1. Use new gaskets. It should be noted that the three o-rings provided for sealing the oil galleries between the timing gear cover and cranckase - (See two a-rings to the left of the timing gear) are not omitted nor that they fall out when the timing gear cover is positioned on the crankcase.

168

1.12.18 Rubber Plugs on Timing Gear Cover

• 2. Ensure that the dowel pins are firmly seated. • 3. Place one rubber plug on each end of the counter pressure oil line and

install in the timing gear cover so that the open end of the upper plug faces the crankcase while the open end of the lower plug is inside the timing gear cover (see Fig. 154).

• 4. Inspect oil seal at crankshaft pulley and replace if worn or damaged. • 5. Use new gasket under generator carrier. • 6. Torque retaining nuts of timing gear cover to 2 mkp (14. 5 lbs/ft).

169

1.12.19 Flywheel R/R

Special Tools: P 44 Hex socket (36 mm)

The flywheel is attached to the crankshaft by way of a gland nut; eight dowel pins transmit the torque forces. A soft iron gasket is installed between the flywheel and the crankshaft. Oil sealing is accomplished by an oil seal installed in the crankcase at Bearing 1; the seal rides on the flywheel hub. The gland nut contains a - pilot bushing which supports one end of the transmission input shaft.

1. Flywheel 2. Oil seal 3. Spacer 4. G land nut 5. Gasket 6. Spring washer 7. Crankcase 8. Bearing 1 9. Crankshaft 10. Pilot bushing 11. Oil gallery 12. Dowel pin 13. Soft iron gasket

170

Removal

1. Remove clutch pressure plate. 2. Withdraw clutch plate, 3. Remove gland nut using P 44 hex socket, 4. Withdraw flywheel.


171

1.12.20 Flywheel Installation

1. Inspect flywheel starter ring for serviceable condition of gear teeth; slightly pounded teeth may be dressed with a file.

2. Check dowel pin seats in flywheel; if the seats appear peened, install a new flywheel.

3. Check dowel pins in the crankshaft, replace if necessary. 4. Use new soft iron gasket, 5. Check and adjust crankshaft end play. 6. Check pilot bushing in gland nut for wear. 7. If the pilot bushing requires replacement, install new needle bearing with

gland nut. 8. Torque gland nut to 45-50 mkp (326-362 lbs/ft). 9. Check flywheel for runout. Maximum lateral runout is 0.3 mm (0.012 in),

measured in the middle of the clutch plate contact area. Maximum vertical runout is 0,1 mm (0.004 in). Note specifications in the table of tolerances.

172

1.12.21 Dowel Pin Position

Crankshaft and flywheel are balanced as a unit and always marked with a number. It should be noted at time of installation that both identifying numbers are same. Replacement flywheels or crankshafts are balanced to 0 so that they are individually relaceable, To ensure proper installation of the flywheel in relation to the crankshaft, two dowel pins have been positioned closer together; this point is identified on the crankshaft and flywheel by the number 1 stamped into both parts.

173

1.12.22 Reconditioning Flywheel

If necessary recondition the flywheel gradually on a lathe (according to table below). Please pay attention to the fact that the bearing surface of the clutch must be reconditioned by the same proportion as the thrust surface of the flywheel.

Measuring point

Original measure (mm)

Grade 1

Grade 2

Grade 3

Tolerance

A 12.3 11.8 11.5 11.2 +/- 0.1

B 22.5 - - - +/- 0.2

C 39.5 38.8 38.4 38.0 +/- 0.2

D 13.25 12.95 12.75 12.55 +/- 0.1

E 3.15 3.1 - - +/- 0.05

r 0.5 0.5 - - - 0.2

b 1 deg 30' - - - -

174

Crankshaft Pulley R/R

1.12.23 Crankshaft Pulley Diagram

1. Oil deflector 2. Bearing 4 3. Oil seal 4. V-belt 5. Spring washer 6. Retaining bolt 7. Woodruff key 8. Crankshaft pulley

Removal

1. Remove V-belt. 2. Remove engine rear shield. 3. Remove crankshaft pulley retaining bolt. 4. Withdraw crankshaft pulley.

175


1. Inspect crankshaft pulley, prior to installation, for good condition of its seat and belt running surfaces.

2. Check for possible pulley runout. 3. Check oil sealing surface of pulley. 4. Check oil seal for absence of damage or wear, replace if necessary.

1.12.24 Flywheel Oil Seal R/R

Special Tools VW 204b Crankshaft oil seal installer

Removal

1. Remove flywheel. Inspect oil sealing surface on flywheel hub. 2. Remove old oil seal. 3. Clean the oil seal seat and apply a thin coat of gasket compound, If

necessary, remove sharp edges from outer surface perimeter, making sure to remove any remaining filings.

Installation

1. Install new oil seal using VW 204b oil seal installer; to install, screw installer into crankshaft end and tighten guide piece which carries the oil seal. The oil seal must rest at the bottom of its seat and must not be slanted in the installation process.

2. Remove installer. 3. Use new soft iron gasket. 4. Instal flywheel; lightly oil the oil sealing surface (hub).

176

1.12.25Camshaft Remove / Install

Removal

1. Disassemble crankcase (41 En). 2. Withdraw camshaft.

Installation

Camshaft

• 1. Check for firm attachment of camshaft gear to camshaft. • 2. Check camshaft for wear at bearing journals and camshaft lobes, i.e.,

rippled wear in lift ramps or slanted wear, in relation to camshaft axis, or cam lobe races, End play specifications are shown in the table of tolerances.

177

1.12.26 Timing Gear Position

• 3. Check camshaft for whip. • 4. Check camshaft gear for good condition and proper tooth contact. • 5. When installed, the camshaft gear tooth marked "0" lies between two

crankshaft gear teeth bearing a punch mark each.

178

1.12.27 Camshaft Gear Marking

• 6. Check gear backlash over the entire circumference of the camshaft gear. Correct backlash, in assembled crankcase, between the camshaft gear and crankshaft gear is 0,015 - 0,04 mm (0.0006 - 0.0016 in). To measure, move gears back and forth while taking readings with a dial gauge and measuring the entire circumference of the camshaft gear, To facilitate proper backlash adjustment, camshafts are furnished with camshaft gears in five sizes. The camshaft gears are marked on the camshaft side with electrically inscribed or mechanically stamped identifica don num bers such as 0, +1, +2, -1, and -2, The numbers show, in hundreds of one millimeter, by how much the pitch circle radius differs from standard size (0); it identifies a standard gear 0, oversize of +1 or +2 (+ 1/100 or +2/100 mm), or undersize -gears. Note: Do not confuse the number "0" with the timing mark "o" on the other side of the gear. The crankshaft gear is supplied in one size only and no identifica tion is necessary .

• 7. Lubricate camshaft with graphite oil and install. • 8. Do not fail to install camshaft end plug. • 9. When assembling a new crankcase, check camshaft for snug but easy

rotation; if necessary check camshaft bearings with machinist's blue and smoothen bearing seats in crankcase with a scraper. Note: When installing a new camshaft gear ensure that the timing mark on the camshaft gear, its nearest mounting bolt bore, and the oil pump drive slot on the camshaft end align in an almost straight line. Before drilling the 5,8 mm ( 0.228 in) dowel pin holes, and tapering these from the camshaft side, check the gear for runout, The three dowel pins must be firmly seated in the camshaft gear and additionally secured by three punch strikes each. If necessary, install larger dowel pins which may be locally manufactured from high-grade steel. Torque retaining bolts to 2,5 mkp (18 lbs/ft).

179

Crankshaft with Connecting Rods R/R

Removal

1. Disassemble crankcase (41 En). 2. Withdraw camshaft. 3. Remove crankshaft with connecting rods. 4. Mark insert of Bearing 2 and 3.

1.12.28 Install Crankshaft

1. Lightly bevel bearing seat edges at the crankcase joint to prevent gouging as a result of bearing preload upon reassembly of crankcase,

2. Check dowel pin in Bearing 1 for firm seating. 3. Oil passages in crankshaft journals and bearings must not have sharp

edges in evidence. 4. Install in crankcase insert halves of Bearing 2 and 3. 5. Place insert of Bearing 1 on crankshaft journal so that the off-centered

dowel pin bore is closest to the flywheel side. 6. Insert crankshaft. 7. Note timing marks when installing camshaft.

180

1.12.29 Connecting Rods R/R

Special Tools VW 310a Crankshaft bench mount

Removal

1. Remove crankshaft and place into VW 310a bench mount (50 En). 2. Remove connecting rod retaining nuts, remove connecting rods and

caps.

181

1.12.30 Torque Connecting Rods


• 1. Check connecting rod weight: Maximum permissible weight difference between connecting rods of one engine is 6 g ( 0.211 oz.).

• 2. Check piston pin bushing. The piston pin should enter a new bushing under light finger pressure.

• 3. Check connecting rod alignment and correct if necessary. • 4. Upon thorough cleaning of all parts install connecting rod inserts and

assemble connecting rods. The identification number stamped into the side of the connecting rod and its bearing cap should be on the same side when assembled.

• 5. Torque connecting rod retaining nuts to 4.5 mkp (32.5 lbs/ft).

182

1.12.31 Tap to Rods Relieve Stress

• 6. Visually check if connecting rod and its bearing cap have actually joined, that is, if no obstruction is in the joint.

• 7. Minor stresses which may result from tightening the connecting rod retaining nuts can be relieved through light hammer blows. The connecting rods, oiled prior to installation, should tip freely under their own weight. Under no circumstances may bearings be dressed or reworked to fit.

183

1.12.32 Check Clearance

• 8. Check lateral clearance between connecting rods and crankshaft (0.15-0.20 mm) (0.006 to 0.008 in).

184

1.12.33 Installing Connecting Rod Bushings

(Connecting rods removed from engine) If clearance between piston pin and bushing is excessive, install new bushings in the connecting rods by noting the following points:

1. Install new bushings on a press using a round block. 2. Bring bushing bore to correct size by means of precision drilling, 3. It is in no case permissible to rebore worn bushingS and fit these with

oversize piston pins. State weight when ordering connecting rods,

Note: If at all possible, connecting rod bushings should be brought to correct bore size only by means of precision drilling. Only in cases of emergency, when precision drilling equipment is not at hand, or if economic reasons prevent the removal of crankshaft from the engine, is it permissable to ream the connecting rod bushings, and in such. cases only with a well guided reamer and with the greatest of care.

1.12.34 Measuring and Realigning Connecting Rods

Special Tools: P 14b Connecting rod measuring fixture

Measuring

1. Remove crankshaft and take off connecting rods, Mark connecting rods and caps to ensure reassembly in original locations and posi tions.

2. Remove bearing inserts. 3. Install connecting rod in P 14b measuring fixture. 4. Insert measuring pin into connecting rod and check for twists or bends.

Aligning

185

1.12.35 Checking for Twisted Connecting Rods

Connecting rods may be realigned in the measuring fixture with the use of a MATRA aligning tool, or with other commercial aligning tools.

186

1.13 CRANKSHAFT

Disassembling and Reassembling Crankshaft

Special Tools:

• VW 161a Lock ring pliers, for removing and installing gear lock ring on crankshaft.

• VW 202 Puller with o VW 202a Puller jaws o VW 202f Block -- for removing gears from crankshaft

• VW 310a Crankshaft bench mount • VW 427 Guide tube, for installing camshaft drive gear, spacer. and

distributor drive gear on crankshaft. • VW 428 Tapered guide tube, for installing gear lock ring on crankshaft

Specifications for Plain Bearing Crankshaft

Stroke mm 74 (2.913 in)

Connecting rod journal diameter mm 53 (2.0866 in)

Main bearing journal diameter mm Bearing 1: 50 mm (1.9685 in)

Bearing 2: 55 mm (2.1654 in)

Bearing 3: 55 mm (2.1654 in)

Bearing 4: 40 mm (1.5748 in)

187

1.13.1 Crankshaft Disassembly

1. Install crankshaft in VW 310a bench mount (mount has 8 seating holes). 2. Remove connecting rods (51 En). 3. Using VW 161a lock ring pliers, remove gear lock ring from crankshaft. 4. Remove distributor drive gear, spacer, and camshaft drive gear from

crankshaft using VW 202 puller with VW 202a puller jaws and VW 202f block, Minor scoring in the seating surface should be removed with care although the dressing must not impair the press fit of the gears.

188

1.13.2 Crankshaft Reassembly

Reassembly is accomplished in reversed order of the above by noting the following points:

1. Check crankshaft for whip, cracks (acoustical sound test), or wear, Replace crankshaft if necessary, The crankshaft may be reground. The crankshaft can only be reground at the factory.

2. To simplify reassembly, mark insert of Bearing 1 at the crankcase joint (this aids in locating the dowel pin seat).

3. Insert Woodruff key for camshaft and distributor drive gears. 4. Inspect camshaft drive gear for wear and tooth contact, heat to 80 deg C

(176 deg F), and press onto crankshaft, with chamfered side facing flywheel, using VW 427 guide tube.

5. Check distributor drive gear for wear, replace if necessary. Heat gear to 80 deg F (176 deg F) and press onto crankshaft using VW 427 guide tube.

6. Install gear lock ring on crankshaft, use VW 428 tapered guide tube to prevent damaging the bearing journal. Check gears for firm seating when cool.

7. Clear oil galleries with compressed air, flush with oil. 8. Install connecting rods.

189

Checking and Adjusting Crankshaft End Play

Special Tools P 17 Dial gauge holder, for mea suring end play in assembled engine.

Checking End Play End play should be 0,14 - 0,17 mm ( 0.0055 to 0.0067 in), wear limit 0,22 mm ( 0.0087 in). End play should be adjusted before installing the crankshaft. The use of more than one soft iron gaskets is not permissible.

1.13.3 Crankshaft End Play

1. Properly position Bearing 1 on Journal 1 2. Install spacer of calculated thickness. The spacers are available in

thicknesses from 0,8 to 1.05 mm (0.0315 to 00413 in) and are marked alphabetically from A through F.

190

1.13.4 Measure End Play

• Attach flywheel to crankshaft and torque gland nut to 45-50 mkp (326-362 lbs/ft).

• Measure end play with feeler gauge.

End play is measured at the crankshaft pulley when the engine is installed in vehicle, and at the flywheel when the engine is removed. In both cases use a dial gauge mounted in P 17 holder. When measuring end play at the crankshaft pulley, attach gauge holder to a stud in the timing gear cover; when measuring at the flywheel, attach the holder to the engine mounting flange by means of a bolt.

191

1.13.5 Calculating End Play

1. Place gauge base on the end of the crankshaft and measure distance from crankshaft end to the thrust flank of Bearing 1 (crankshaft pushed to flywheel).

2. Place gauge base on the flywheel hub and measure depth of seat (flywheel hub takes up the thrust, hub seat rests on crankshaft end).

From the difference between both readings, and considering the thickness of the soft iron gasket, the thickness of the required spacer may be determined. The soft iron gasket thickness is 0.10 - O. 14 mm (0.004 - 0.006 in) The use of more than one soft iron gaskets is not permissible.

192

Example: (1 mm = 0.03937 in.)

Crankshaft-end to Bearing 1 thrust flank 4.015 mm

Crankshaft seat depth in flywheel hub - 3.025 mm

O.990 mm

Soft iron gasket thickness + 0.100 mm

1.090 mm

Required end play - 0.140 mm

Spacer Thickness = 0.950 mm

193

1.13.6 Reconditioning Crankshaft

Crankshafts can only be reground at the factory and/or obtained through the exchange service, as these crankshafts demand a special treatment of material. Appropriate undersize bearings are available within the spare part program; it must be determined however, if the main bearing bores in the crankcase are standard or oversize.

Main Bearing and Crankshaft Journal Dimensions (1 mm = .03937 in) MAIN BEARINGS

Nomenclature Version Bearing 2 and 3

Bearing 1

Crankshaft Journal

Standard Diameter 54.990-54.971

49.991-49.975

Bearing Insert Inside standard

Wall thickness

2.615 - 2.603

5.096- 5.108

Outside standard

Outside diameter

- 60.29 + 0.02

Crankcase Bore Standard Diameter 60.24 +/- 0.005

60.24 +/- 0.005

Crankshaft Journal

Standard Diameter 54.990-54.971

49.991-49.975

Bearing Insert Inside standard

Wall thickness

2.740- 2.728

5.221 - 5.233

Outside oversize

Outside diameter

- 60.54 + O.02

Crankcase Bore

Oversize Diameter 60.49 +/- O.005

60.49 +/- 0.005

Crankshaft Journal

1st undersize

Diameter 54.740-54.721

49.741-49.725

194

Bearing Insert Inside undersize

Wall thickness

2.740- 2.728

5.221 - 5.233

Outside standard

Outside diameter

- 60.29 + 0.02

Crankcase Bore

Standard Diameter 60.24 +/- 0.005

60.24 +/- O.005

Crankshaft Journal

1st undersize

Diameter 54.740-54.721

49.741-49.725


Wall thickness

2.865- 2.853

5.346- 5.358

Outside oversize

Outside diameter

- 60.54 +/- O.02

Crankcase Bore

Oversize Diameter 60.49 +/- 0.005

60.49 +/- 0.005

Cankshaft Journal

2nd undersize

Diameter 54.490-54.471

49.491-49.475

Bearing Insert

Inside undersize

Wall thickness

2.865- 2.853

5.346- 5.358

Outside standard

Outside diameter

- 60.29 + 0.02

Crankcase Bore


60.24 +/- 0.005

Crankshaft journal

2nd undersize

Diameter 54.490-54.471

49.491-49.475


Wall thickness

2.990 - 2.978

5.471 - 5.483

Outside Outside - 60.54 +

195

oversize diameter 0.02

Crankcase Bore


60.49 +/- 0.005

Crankshaft Journal

3rd undersize

Diameter 54.240-54.221

49.241-49.225


Wall thickness

2.990- 2.978

5.471- 5.483

Outside standard

Outside diameter

- 60.29 + 0.02

Crankcase Bore


60.24 +/- 0.005

Crankshaft Journal

3rd undersize

Diameter 54.240-54.221

49.241-49.225


Wall thickness

3.115- 3.103

-

Outside oversize

Outside diameter

- 60.54 + 0.02

Crnakcase Bore


60.49 +/- 0.005

196

1.13.7 Measuring Bearing Inserts

Measuring point for establishing thickness of bearing inserts.

197

1.14 THE CLUTCH

Description of the Clutch

General A dry single plate clutch is incorporated in the flywheel between engine and transmission. The spring cushioned clutch disc has friction linings on both sides. It rides in the splined input shaft and has axial freedom of movement. The diaphragm spring, together with the clutch assembly, is centrally mounted in the flywheel. In engaged condition, the clutch disc is held against the flywheel by the pressure plate upon which the diaphragm spring acts, thus providing a mechanical lock between the engine and transmission.

1.14.1 Diagram of the Clutch

The clutch control fork, mounted in the transmission housing, carries the throwout bearing. The throwout bearing is permanently lubricated and requires no maintenance. Clutch actuation at disengagement is by way of the clutch pedal, clutch cable, control fork, and throwout bearing. The throwout bearing exerts pressure upon the segments of the diaphragm spring, displacing it axially. The resulting deflection of the diaphragm spring relieves pressure from the pressure plate and, thus, from the clutch disc, resulting in disengagement of engine from the transmission. Clutch maintenance is limited to adjustment of the clutch pedal clearance of 20-25 mm (3/4 to 1 in.) in the course of normal clutch lining wear, and also to the adjustment of the clutch pedal travel limiter.

198

1.14.2 Remove Clutch

1. Remove engine and detach from transmission. 2. Evenly loosen clutch retaining bolts, slackening each by one or two turns

at a time and switching in a cross sequence until the spring pressure is relieved, to a void distortion of spring housing.

3. Withdraw clutch assembly. 4. Withdraw clutch disc,

199

1.14.3 Clutch Installation

1. Clean clutch contact surface in flywheel and check for wear, If necessary reface surface and polish with fine polishing cloth. Replace flywheel if excessively worn.

2. Check clutch disc for lining wear, lateral run out, and evenly working undulated spacers between both lining discs. Devote special attention to riveted joints securing flange to disc, If necessary, replace complete clutch disc assembly.

3. Check torsion damper for firm seating and inspect springs for cracks. If in defective condition, replace clutch disc assembly.

4. Inspect clutch assembly. 5. Check throwout bearing for wear and smooth rotation, replace if

necessary. 6. Check control fork seat in transmission housing for wear and good

seating, repair if defective. 7. Fill bushing in gland nut at flywheel with approx, 2 cc (.12 cu, in,)

graphite grease or MoS2 compound, 8. Install clutch disc with the aid of an arbor or a shortened transmission

input shaft. 9. Push clutch assembly onto aligning dowels in flywheel. If the flywheel is

not provided with dowel pins, align clutch assembly with the help of P 219 locating arbor.

10. Evenly tighten clutch retaining bolts, turning each by one or two turns at a time in a cross sequence to avoid distortion of spring housing, Use only 10 K hex bolts with lock washers, Torque bolts to 3,5 mkp (25,3 lbs/ft).

11. With transmission attached to the engine pull clutch control lever in direction of arrow, The distance between the lever and transmission housing should still be not less than 20 mm (4/5 in,),

200

Inspecting Clutch Disk

1.14.4 Measure Clutch Thickness

1. The clutch linings are riveted to undulated spring segments which curve from side to side and provide a cushioning effect in the clutch disc. It is essential for proper functioning of the clutch that the cushioning action of individual segments is equal in all sections of the clutch disc.

2. The clutch disc should slide freely on the splined input shaft but it must not show evidence of radial play,

3. Inspect clutch linings. If the linings are oiled, scorched, torn, or worn considerably. install a new clutch disc. Visible formation of cracks in the lining surface between the rivets can be disregarded. Clutch disc with riveted linings: Compressed thickness = 9,2 +/- 0,2 mm (0.362 +/- 0.008 in) Wear limit = 8 - 7. 8 mm (0.315 - 0.307 in) Measurements are taken between both friction surfaces of the clutch disc. Thickness A, decompressed = 10,1 - 0.4 mm (0.398 - 0.016 in)

201

1.14.5 Check Clutch Disk for Runout

4. Check clutch disc for run out at linings: Permissible runout is 0.6 mm (0.024 in).

202

1.14.6 Inspecting Clutch Assembly

Inspection The Fichtel-Sachs MX 200 K clutch has been designed without provision for repair or overhaul. The clutch inspection is, therefore, limited to a thorough visual examination of the component parts.

1.14.7 Check Pressure Plate

1. Clean the clutch. 2. Check diaphragm spring segments for wear in the throwout bearing contact area. Groove formation up to a depth of O. 3mm (0.012 in) may be disregarded. 3. Check pressure plate contact surface for cracks, scorching, or wear. Pressure plates warped inward up to 0,3 mm (0.012 in) (see illustration) are still serviceable.

203

1.14.8 Check Clutch Attachment Points

4. Check attachment points of diaphragm spring and spring housing for cracks. Check rivets for firm seating. Clutch assemblies with damaged or loose rivet connections must be replaced.

204

1.14.9 Check Wear of Rivet Heads

5. The diaphragm spring is riveted to the spring housing with two wire ring spacers in between. Clutch assemblies. showing visible wear at the rivet heads or at the wire ring spacers should be replaced. 6. Lightly coat the diaphragm spring seat at the wire ring seating area with MoS2 paste prior to installation.

205

1.14.10 Adjusting Clutch

General Both ends of the clutch cable have threads and may be adjusted at either the clutch control lever in transmission housing or at the clutch pedal. The clutch is correctly adjusted when clutch pedal free travel is 20 - 25 mm (3/4 to 1 in,). The adjustment should be made with care since insufficient clearance will result in clutch slippage followed by burnt linings.

Adjusting Clutch Free-Play at Control Lever

1.14.11 Adjust Clutch Free-Play at Control Lever

1. With car on stands, loosen lock nut at clutch lever clevis. 2. Adjust clutch free travel (20-25 mm or 3/4 to 1 in.) by turning the

adjusting nut. 3. Tighten lock nut when adjustment is made.

206

1.14.12 Adjust Free-Play at Clutch Pedal

1. Remove rubber mat located in front of passenger seat. 2. Raise rubber cover from center tunnel and fold back. 3. Loosen lock nut in threaded part of cable at clevis. Pull retaining spring

off clevis pin and withdraw pin, 4. Adjust by turning the clevis. The clevis may be turned only until it is

flush with the cable bolt. 5. Tighten lock nut when adjustment is completed check clevis pin retaining

spring for proper seating. Thoroughly lubricate threaded part of cable end.

207

1.14.13 Adjusting Clutch Travel Limits

Note: The diaphragm spring clutch requires an exactly limited clutch pedal travel. Whenever work has been performed on the clutch, check and correctly adjust the clutch pedal travel.

Checking

1. Bring transmission to operating temperature. 2. Depress clutch pedal to stop. At this point the reverse gear should

silently engage, allowing a quick moment of pause between pedal depression and gearshift movement.

208

1.14.14 Adjusting Clutch Pedal Travel

1. Remove rubber mat. 2. Loosen both limiter retaining bolts with a 3 mm Allen-head wrench. 3. Slide the limiter up or down, as required. 4. Tighten limiter retaining bolts. 5. Check clutch pedal travel as outlined above.

209

1.15 TOLERANCES AND WEAR LIMITS

1.15.1 Cylinder Seat Depth in Cylinder Head

Measuring point Tolerance (new) Wear Limit

1. Cylinder seat depth in cylinder head

9.500-9.600 mm (0.374-0.378 in)

10.000 mmm (0.3937 in)

210

1.15.2 Cylinder Bore Ovality

Measuring point Tolerance (new)

Wear Limit

2. Cylinder bore ovality, B minus A

n/a 0.020 mm (0.0008 in)

1.15.3 Piston Ring Gap


6. Piston ring gap 0.15-0.30 mm (0.0059-0.0118 in) 0.95 (0.0374)

211

1.15.4 Piston Pin to Connecting Rod Clearance


9. Piston pin to connecting rod clearance

0.012-0.028 mm (0.0005-0.0011 in)

0.042 mm (0.0017 in)

1.15.5 Crank Pin to Connecting Rod Clearance


10. Crank pin to connecting rod clearance

0.040-0.092 mm (0.0016-0.0036 in)

0.130 mm (0.0051 in)

212

1.15.6 Crankshaft to Main Bearing Clearance


11. Crankshaft to main bearing clearance (bearings installed)

a. Bearing 1. 0.028-0.078 mm (0.0011-0.0031 in)

0.170 mm (0.0067 in)

b. Bearing 2 and 3. 0.046-0.100 mm (0.0018-0.0039 in)

0.170 mm (0.0067 in)

c. Bearing 4. 0.040-0.104 mm (0.0016-0.0041 in)

0.170 mm (0.0067 in)

213

1.15.7 Crankshaft Runout


12. Crankshaft runout at Bearing 2 and 4 (Bearing 1 and 3 on V -blocks)

max. 0.020 mm (0.0008 in)

0.030 mm (0.0012 in)

214

1.15.8 Crankshaft to Crankshaft Thrust Bearing


13. Crankshaft to crankshaft thrust bearing

0.13-0.18 mm (0.0051-0.0071 in)

0.3 mm (0.0118 in)

215

1.15.9 Diagram of the Clutch

The clutch control fork, mounted in the transmission housing, carries the throwout bearing. The throwout bearing is permanently lubricated and requires no maintenance. Clutch actuation at disengagement is by way of the clutch pedal, clutch cable, control fork, and throwout bearing. The throwout bearing exerts pressure upon the segments of the diaphragm spring, displacing it axially. The resulting deflection of the diaphragm spring relieves pressure from the pressure plate and, thus, from the clutch disc, resulting in disengagement of engine from the transmission. Clutch maintenance is limited to adjustment of the clutch pedal clearance of 20-25 mm (3/4 to 1 in.) in the course of normal clutch lining wear, and also to the adjustment of the clutch pedal travel limiter.

216

1.15.10 Crankshaft Pulley Runout


17. Crankshaft pulley runout

vertical. A max. 0.250 mm (0.0098 in)

B max. 0.250 mm (0.0098 in)

217

1.15.11 Camshaft Bearing Clearance


19a. Camshaft bearing clearance

0.020-0.054 mm (0.0008-0.0021 in)

0.120 mm (0.0047 in)

218

1.15.12 Camshaft End Play at Thrust End


19b. Camshaft end play at thrust end

0.040-0.080 mm (0.0016-0.0031 in)

0.100 mm (0.0039 in)

219

1.15.13 Camshaft Center Bearing Runout

Measuring point Tolerance (new)

Wear Limit

19c. Camshaft center bearing runout (camshaft mounted on centers)

0.020 mm (0.0008 in)

0.025 mm (0.0010 in)

1.15.14 Lateral Runout


20. Timing gear run out (gear bolted and pinned to camshaft): Lateral runout

max. 0.100 mm (0.0039 in)

220

1.15.15 Vertical Runout


20c. Timing gear runout: Vertical runout

0.025 mm (0.0010 in)

0.040 mm (0.0016 in)

1.15.16 Flywheel Lateral Runout


21a. Flywheel: Lateral runout measured at starter ring (A):

max. 0.300 mm (0.0118 in)

221

Flywheel Lateral Runout


21b. Flywheel: Lateral runout, measured in clutch plate recess (B):

max 0.040 mm (0.0016 in)

1.15.17 Flywheel Vertical Runout


21c. Flywheel: Vertical runout, measured at starter ring (C):

max 0.020 mm (0.0008 in)

222

Flywheel Vertical Runout


21d. Flywheel: Vertical runout, measured in clutch disk recess (D):

max 0.100 mm (0.0039 in)

1.15.18 Flywheel Diam of Oil Sealing Surface


21e. Flywheel: Diameter of oil sealing surface at hub (E):

59.000-60.100 mm (2.3583-2.3661 in)

59.700 mm (2.3403 in)

223

1.15.19 Flywheel Depth of Recess to Web


21f. Flywheel: Depth of recess to web (F):

6.3-6.85 mm (0.2480-0.2697 in)

224

1.15.20 Flywheel Web Thickness


21g. Flywheel: Web thickness (G):

6.3-6.85 mm (0.2480 - 0.2697 in)

min 4.800 mm (0.1890 in)

1.15.21 Flywheel Width of Oil Sealing Area


21h. Flywheel: Width of oil sealing area (H):

9.250 - 10.250 mm (0.3642 - 0.4035 in)

225

1.15.22 Valve Guide Clearances


23a. Valve guide to valve stem clearance. a) Valve guild inside diameter

10.025-10.040 mm (0.3947-0.3953 in)

10.070 mm (0.3965 in)

23b. Valve guide to valve stem clearance. b) Intake valve clearance in bore

0.035-0.060 mm (0.0014-0.0024 in)

0.120 mm (0.0047 in)

23c. Valve guide to valve stem clearance. c) Exhaust valve clearance in bore

0.055-0.080 mm (0.0022-0.0031 in)

0.120 mm (0.0047 in)

226

1.15.23 Valve Seat


24a. Valve Seat: Intake seat width a)

1.25 +/- 0.15 (0.0492 +/- 0.0059 in)

24b. Valve Seat: Exhaust seat width a)

1.55 +/- 0.15 (0.0610 +/- 0.0059 in)

24c. Valve Seat: Lateral Runout of valve head to seat

0.010 (0.0004 in)

227

1.15.24 Valve Springs


25a. Valve Spring length decompressed 47 mm (1.85 in)

25b. Valve Spring length installed, intake 41 mm (1.61 in)

25c. Valve Spring length installed, exhaust

40.5 mm (1.59 in)

25d. Valve Spring pressure when compressed to 41 mm length

36 +/- 1.5 kp (79 +/- 3.3 lbs)

25e. Valve Spring pressure when compressed to 30.1 mm length

97 +/- 2.5 kp (213 +/- 5.5 lbs)

228

1.15.25 Valve Spring Lengths


25d. Valve Spring pressure when compressed to 41 mm length

36 +/- 1.5 kp (79 +/- 3.3 lbs)

25e. Valve Spring pressure when compressed to 30.1 mm length

97 +/- 2.5 kp (213 +/- 5.5 lbs)

229

1.15.26 Valve Lifter Dimensions

Measuring point

Tolerance (new) Wear Limit

28. Valve Lifter

bore in crankcase (diam): 12.000-12.018 (0.475-0.4731)

12.060 (0.4748)

diameter: 11.966-11.984 (.4711-0.4718) 11.945 (0.4703)

to crankcase bore clearance: 0.016-0.052 (0.0006-0.0020)

0.100 (0.0039)

230

1.15 27 Oil Pump

Measuring point

Tolerance (new) Wear Limit

30.Oil Pump Pump gears extend beyond housing (no gasket): 0.06-0.125 (0.0024-0.0049)

Thickness of compressed gasket (A): 0.16 (0.0063)

Gear end play, with gasket and cover installed (B): 0.035-0.10 (0.0014-0.0039)

0.20 (0.0079)

Gear backlash: 0.030-0.080 (0.0012-0.0031)

231

1.15.28 Pressure Relief Spring


31. Spring for pressure releif valve in crankcase and timing gear cover

Free length: 66 mm (2.6 in)

Spring pressure when compressed to 49 mm: 4.7 kp +/- 7% (10.4 lbs +/- 7%)

Spring wire cross section (diam): 1.4 (0.55)

232

1.15.29 Torque Values for Bolts and Nuts

(1 mkp = 7.233 lbs/ft)

Fastener mkp lbs/ft

Crankcase bolts 2.5 18

Timing gear cover nuts 2.0 14.5

Connecting rod nuts (without safety plates) 4.5 32.5

Cap nuts for through - bolts 4.0 28.9

Cylinder head nuts 3.0 21.7

Rocker arm carrier retaining bolts 5.0 36.2

Camshaft gear retaining nuts 2.5 18

Rocker arm shaft retaining nuts 2-2.5 14.5-18

Blower impeller retaining nut 10.0 72.3

Flywheel gland nut 35-37 253-268

233

2. FUEL 2.1 FUEL SYSTEM DESCRIPTION

The Fuel System Consists of the Following Major Components:

1. Fuel tank 2. Fuel lines 3. Mechanical fuel pump 4. Two double - throat downdraft carburetors with air cleaner

The fuel tank is located under the front lid beneath the luggage compartment. It has a capacity of 62 liters (16.4 US gal.) of which 7 liters (1. 8 US gal.) are the reserve. The fuel supply line leads to the fuel pump through the frame tunnel. The fuel pump is actuated by a cam, machined into the distributor pinion shaft, over an actuating plunger. Each bank of two cylinders has one double-throat downdraft carburetor with ail accelerating pump. The air cleaners or induction silencers remove dust and dirt from the induction air.

234

2.2 DESCRIPTION OF THE SOLEX 40 P II - 4 CARBURETOR

2.2.1 Solex 40 P II-4 Solid Shaft Parts list

235

Spare parts for carburetor Solex 40 P II-4 with through throttle spindle 616/36/37

Fig No

Part No Description Qty

1 616.100.975.00 Carburetor housing 1

2 616.100.976.00 Stud 2

3 616.100.912.02 Throttle Spindle 1

4 616.108.912.00 Throttle oval 2

5 616.100.917.00 Throttle butterfly fixing screw 4

6 616.100.978.00 Throttle lever for right caburetor with thrust bloc

1

(6) 616.100.977.00 Throttle lever for left caburetor with thrust bloc

1

7 616.100.918.00 Pump intermediate actuating lever 1

8 616.100.921.00 Cylindrical pin for intermediate lever 1

9 616.100.922.00 Return spring for intermediate lever 1

10 616.100.923.00 Slow running adjustment screw 1

11 616.100.814.00 Pressure spring for slow running adjustment screw

1

12 616.100.815.00 Washer for throttle spindle 1

13 616.100.913.00 Throttle spindle end nut 2

14 616.100.926.00 Lock washer for hexagon nut 2

15 616.100.927.01 Volume control screw 2

16 616.100.814.00 Pressure spring for volume control screw 2

17 616.100.928.00 Screw plug 1

18 616.100.929.00 Gasket for screw plug 1

19 616.100.931.00 Choke tube 32 2

20 616.100.931.00 Fixing screw for choke tube 2

21 616.100.935.00 Hexagon nut 2

22 616.100.933.00 Pre-emulsifier 2

23 616.100.931.00 Fixing screw 2

24 616.100.932.00 Hexagon nut 2

25 616.100.932.02 Idling jet air bleed (u) 1.8 2

26 616.100.901.02 Idling jet (g) 57.5 2

236

27 616.100.914.01 Main jet carrier 2

28 616.100.915.00 Gasket 2

29 547.100.937.02 Main jet 120 2

29 616.100.935.00 Main jet 115 for USA 2

30 616.100.936.00 Pump jet (Gp) 50 2

31 616.100.937.00 Gasket 2

32 616.100.938.00 Jet 0.7 cal. 2

33 616.100.907.02 Emulsion tube No. 25 2

34 616.100.900.02 Air correction jet (a) 180 2

35 616.100.906.01 Float 7.4 gr 1

36 616.100.911.01 Float pivot 1

37 616.100.940.00 Arm for adjustment of fuel level 1

38 616.100.911.00 Pivot for arm 1

39 616.100.941.00 Adjusting screw 1

40 616.100.932.00 Hexagon nut 1

41 616.100.942.00 Lock plate 1

42 616.100.943.01 Ball Valve 1

43 616.100.944.00 Screen 1

44 616.100.937.00 Gasket 1

45 692.100.966.01 Pump injector 0.35 1

46 692.100.697.01 Pump injector 0.35 1

47 616.100.947.00 Fixing screw 2

48 692.100.968.00 Gasket 2

49-55 692.100.969.00 Accelerator pump compl. 1

49 616.100.950.00 Pump body 1

50 616.100.951.00 Pump diaphram 1

51 616.100.952.00 Diaphram sprint 1

52-54 692.100.970.00 Cover with pump lever 1

52 616.100.954.00 Cover 1

53 692.100.971.00 Lever 1

54 616.100.956.00 Pump lever spindle 1

55 616.100.939.00 Fixing screw 2

56 616.100.957.00 Gasket 1

237

57 616.100.958.00 Pump fixing screw 4

58-65 692.100.972.00 Pump control rod complete 1

58 692.100.973.00 Pump control rod 1

59 616.100.961.00 Spring 1

60 616.100.962.00 Washer 1

61 616.100.963.00 Split pin 1

62 616.100.964.00 Nut 1

63 616.100.925.00 Hexagon nut 1

64 616.100.965.00 Washer 2

65 616.100.966.00 Split pin 2

66 616.100.967.02 Float chamber cover 1

67 616.100.968.00 Gasket for cover 1

68 616.100.969.00 Securing screw 2

69 616.100.970.00 Pressure spring for securing screw 2

70 616.100.971.00 Needel valve 1.75 with ball 1

71 616.108.423.00 Gasket for needle valve 1

72 616.100.867.00 Hollow bolt 1

73 616.108.423.00 Gasket 2

74 616.100.972.00 Float chamber assembley screw 7

75 616.100.973.00 Spring washer for screw 7

76 692.100.974.00 Support 1

77 616.100.934.00 Float chamber assembly screw 1

78 616.100.973.00 Spring washer 1

79 999.522.003.02 Spring, between holder and throttle lever 1

238

2.2.2 Solex 40 PII-4 Split Shaft Parts List

LATER CARS

239

Spare parts for carburetor Solex 40 P II-4 with divided throttle spindle.

Fig No

Part No Description Qty

1 616.100.975.02 Carburetor housing for carburetor II 1

1 616.100.975.01 Carburetor housing for carburetor I 1

2 616.100.946.00 Stud 2

3 616.100.912.05 Throttle spindle 1

3a 616.100.912.06 Throttle spindle 1

4 616.100.909.03 Throttle 2

5 616.100.917.00 Fixing screw 4

6 692.100.991.07 Coupling lever for carburetor I 1

7 547.100.922.03 Throttle lever for carburetor I 1

8 692.100.991.05 Coupling lever for carburetor II 1

9 692.100.991.08 Coupling lever for carburetor I 1

10 692.100.991.06 Coupling lever for carburetor II 1

11 692.100.992.00 Taper pin 2

11a 692.100.993.01 Spring clamp 1

11b 692.100.994.00 Stud 2

12 616.100.923.00 Slow running adjustment 1

13 616.100.814.00 Pressure ring for slow running adjustment screw

1

14 616.100.962.06 Washer 4

14a 616.100.962.02 Washer 1

14b 616.100.962.03 Washer 1

15 616.100.913.00 Hexagon nut 2

16 616.100.926.00 Lock waher 2

17 616.100.991.01 Volume control screw 2

18 616.100.991.01 Pressure spring 2

19 616.100.928.00 Screw plug 1

20 616.100.929.00 asket 1

21 616.100.930.00 Draught catcher 32 2

22 616.100.931.00 Fixing scew 2

23 616.100.932.00 Hexagon nut 2

240

24 616.100.933.01 Diffusor 2

25 616.133.931.00 Fixing screw 2

26 616.100.932.00 Hexagon nut 2

27 616.100.902.08 Idling jet air (u) 1.1 2

28 616.100.777.00 Idling jet (g) 55 2

28a 616.100.901.02 Idling jet (g) 57.5 2

29 616.100.914.01 Main jet carrier 2

30 616.100.915.00 Seal ring 2

31 616.100.935.05 Main jet 122.5 2

32 616.100.708.06 Pump jey (Gp) 40 2

33 616.100.937.00 Seal ring 2

34 616.100.938.00 Jet 0.7 cal 2

35 616.100.907.02 Emulsion tube No. 25 2

36 616.100.900.02 Air correction jet (a) 180 2

37 616.100.906.01 Float 7.4 gr 1

38 616.100.911.01 Float pivot 1

39 616.100.940.00 Arm 1

40 616.100.941.00 Pivot for arm 1

41 616.100.941.00 Ajdusting screw 1

42 616.100.932.00 Hexagon nut 1

43 616.100.942.00 Lock plate 1

44 616.100.943.00 Ball valve 1

45 616.100.944.00 Screen 1

46 616.100.937.00 Joint 1

47 692.100.966.02 Pump injector 0.40 1

692.100.998.00 Spatium 2

48 692.100.967.02 Pump injector 0.40 1

49 616.100.947.00 Fixing screw 2

50 692.100.968.00 Gasket 2

692.100.969.01 Acclerator pump compl. for carburetor I 1

692.100.969.02 Acclerator pump compl. for carburetor II 1

51 616.100.950.01 Pump body 1

52 616.100.951.00 Pump diaphram 1

241

53 616.100.952.01 Diaphram spring 1

616.100.767.02 Pump cover compl. for carburetor I 1

616.100.767.03 Pump cover compl. for carburetor II 1

54 616.100.954.01 Pump cover 1

55 692.100.971.00 Pump lever for carburetor I 1

55a 692.100.971.01 Pump lever for carburetor II 1

56 616.100.956.00 Pivot 1

57 616.100.939.00 Fixing screw 2

58 616.100.957.00 Gasket 1

59 616.100.958.00 Fixing screw 4

692.100.972.02 Pump-perch. compl. 1

692.100.972.03 Pump control rod, compl. 1

60 692.100.973.02 Pump control rod 1

(60) 692.100.973.03 Pump-perch 1

61 616.100.961.00 Pressure spring 1

62 616.100.962.04 Washer 1

64 616.100.925.00 Nut 1

65 616.100.925.00 Hexagon nut 1

66 692.100.995.00 Blankholder 1

67 692.100.996.00 Cheese head screw 1

68 616.100.967.02 Float chamber cover 1

69 616.100.968.00 Float chamber cover gasket 1

70 616.100.969.00 Securing screw 2

71 616.100.970.02 Pressure ring for securing screw 2

72 616.100.971.00 Needle valve 1

73 616.108.423.00 Gasket 1

74 616.100.867.00 Hollow bolt 1

75 616.108.423.00 Gasket 1


77 616.100.973.00 Spring washer 1

79 692.100.974.00 Holder 1


81 616.100.973.00 Spring washer 1

242

82 999.522.003.02 Spring 1

83 692.100.997.00 Shaft-screw 2

84 547.100.922.02 Throttle lever for carburetor II 1

85 616.100.962.05 Washer 1

243

2.2.3 Solex 40 P II-4 Diagram

The Type 912 Porsche is equipped with two SOLEX 40 P II - 4 double-throat downdraft carburetors. The induction throats are 40 mm (1.575in) in diameter. Since the carburetors are located very close to the combustion chambers, cold starting enrichment devices are not needed.

1. Cover retaining screws 2. Power enrichment nozzle 3. Float needle valve 4. Fuel line connector 5. Carburetor cover 6. Cover gasket 7. A ccelerating pump nozzle 8. Carburetor body 9. Idle jet 10. Float level adjustment 11. Accelerating pump 12. A ccelerating pump adjustment 13. A ccelerating pump lever 14. Accelerating pump rod 15. Main jet carrier with jet 16. Idle mixture adjustment 17. Idle speed adjustment 18. Throttle shaft 19. Throttle rerum stop 20. Throttle arm 21. Accelerating pump jet 22. Preatomizer 23. Air correction jet

244

2.2.4 Solex 40 P II-4 Cross Section

The carburetor basically consists of the main body and cover, with a gasket separating the two. The main body contains two induction barrels, each having an independent idle and power metering system. The throttle shaft, which passes through both barrels, controls both throttle valves and carries a throttle return stop and throttle arm.

1. Idle metering jet 2. Idle air bleed 3. Venturi 4. Preatomizer 5. Power enrichment nozzle 6. Air correction jet 7. Emulsioning tube 8. Power enrichment jets 9. Air correction jet 10. Emulsioning tube 11. Power enrichment nozzle 12. Preatomizer 13. Venturi 14. Idle air bleed 15. Idle metering jet 16. Main jet carrier 17. Idle mixture adjustment 18. Throttle valve 19. Float chamber 20. Throttle valve 21. Idle mixture adjustment 22. Main jet carrier

245

2.2.5 Solex 40 P II-4 Lateral Cross Section

The accelerating pump located on the broad side of the carburetor is actuated through an adjustable rod and feeds fuel to both induction throats.

1. Preatomizer 2. Accelerating pump nozzle 3. A ccelerating pump jet 4. Pump diaphragm spring 5. Pump diaphragm 6. Fuel passage, float chamber to check valve 7. Check valve with return flow port 8. Pump rod spring 9. Pump arm

246

2.2.6 The Float Chamber

The float chamber is located between both induction throats. The fuel level in the float chamber is regulated through the buoyancy of the float, that is, the float tang opens or closes the float needle valve. The float level may be adjusted by means of an externally located screw which adjusts the height of the intermediate swivel joint. This provision makes it possible to easily adjust the float level for the particular grade of fuel used. The fuel level may be checked by removing the plug from the inspection port.

1. Float chamber vent 2. Float needle valve 3. Carburetor cover 4. Threads for fuel line connector 5. Inspection port plug 6 Float 6. Float level adjusting screw

247

2.2.7 Idle Metering

The fuel enters through the idle metering jet (g) and mixes with air entering through the idle air bleed (u) forming an emulsion. The emulsion flows to four small discharge ports located near the throttle valve. The amount of emulsion dispensed through the lowest port is controlled by the idle mixture screw (W). The emulsion dispensed into the induction throat through the idle mixture port combines with induction air which is passing through the partly open throttle valve and atomizes into idle mixture. The idle mixture can be leaned out by turning the adjustment screw in, and enriched by turning it out: both screws should be set approximately same. The idle speed adjustment controls the engine idle rpm, i. e.. turning the screw clockwise increases the rpm, and turning it counterclockwise decreases rpm. The idle system employed in this carburetor is an independent system since it draws the fuel from a point before the main jet carrier (Y). As a result, negative pressures prevailing in the induction throat have a continuous effect on the idle metering system and a certain amount of the idle mixture is fed into the induction throats at normal power settings as well.

248

2.2.8 Intermediate Metering

The three discharge ports located above the idle mixture discharge port provide progressive metering at intermediate throttle openings between idling and power. The lowest port, located at the throttle valve level, feeds idle mixture when the throttle is set for idling, while the two upper ports begin to feed the mixture as the throttle begins to open. This metering provision ensures smooth transition from idle speeds to power settings.

249

2.2.9 Partial Load

The fuel flows through the main jet carrier (Y) and the main jet (Gg) into a well which contains the emulsion tube (s) and, directly above it, the air correction jet (a). Vacuum in the induction throat draws the fuel into the preatomizer (X) where it mixes with air and continues to the venturi (K) where it is fully atomized into the combustion mixture. As the vacuum in the induction throat increases, the fuel level in the emulsion tube well decreases and air enters through the air correction jet, mixing with the fuel through orifices in the emulsion tube and effecting a derichment of the fuel air mixture.

250

2.2.10 Full Power with Enrichment

As long as the engine is operating in the mid-rpm range under partial or full throttle load, only the main metering system supplies the fuel. However, as the air velocity in. the induction throat increases with increasing rpm, the vacuum effect in the throat becomes so intense that it begins to draw supplemental fuel from the power enrichment nozzle (q1); the power enrichment system consists of the discharge nozzle ([1) and the metering jet (q2) and draws fuel directly from the float chamber. The enrichment system comes into action when the engine is running under full throttle at high rpm. The main metering system together with its supplemental enrichment system ensures a well balanced and metered fuel! air mixture required for combustion, realizing the desired fuel economy and, yet, maximum power output on demand.

251

2.2.11 Acceleration

A mechanically actuated diaphragm-type accelerating pump is employed. The pump receives fuel directly from the float chamber. When the pump is at rest,. the diaphragm (M) is kept outwards by the diaphragm spring (m). As the throttle valve opens, actuating motion is transmitted to the pump by the pump rod (T) and pump lever (L5), pushing the diaphragm inward against the fuel and forcing it to pass through the pump jet (Gp) and the calibrated injection nozzle (i) into the venturi, enriching the fuel/ air mixture and resulting in smooth engine response at acceleration. The check valve (Hl), in the pump inlet, prevents the fuel from backing up into the float chamber; a second check valve (HZ), at the base of the injection nozzle, prevents air from entering the pump through the injection nozzle when the pump is on the inlet stroke. The amount of fuel dispensed by the pump on its pressure stroke at time of acceleration is predetermined by the length of the pump stroke; the stroke can be adjusted through the pump adjustment (t). The pump jet and the calibrated injection nozzle control only the duration of injection.

252

2.2.12 Check Valve

The check valve assembly (HI) has a return flow passage measuring O.36 mm (0.0142 in) in diameter. This port prevents excessive enrichment of the fuel/ air mixture by fuel dispensed by the fuel pump during acceleration, that is, depending upon the speed with which the throttle pedal is depressed, larger or smaller amounts of fuel are permitted to flow back to the pump.

253

2.2.13 Carburetor Specifications

Carburetor type Solex 40 P II-4 2 per engine

Venturi (K) 32 2 per carburetor

Main jet (Gg) 0120 2 per carburetor

Air correction jet (a) 180 2 per carburetor

Idle metering jet (g) 57.5 2 per carburetor

Idle air bleed (u) 1.8 2 per carburetor

Accelerating pump 72 1 per carburetor

Pump jet (Gp) 50 2 per carburetor

Accelerating pump nozzle

high -type with O.4 restrictor 2 per carburetor

Float needle valve (spring -loaded)

175 1 per carburetor

Float 7,4 g 1 per carburetor

Emulsion tube Nr. 25 2 per carburetor

Main jet carrier 6 2 per carburetor

Intermediate metering ports

1.7; 1.4; 1.0

Injection quantity (warm season)

0.45 cc (7.3 minims) from 2 strokes, each nozzle

2 nozzles per carburetor

Injection quantity (cold season)

0.65 cc (10.6 minims) per carburetor from 2 strokes, each nozzle

2 nozzles per carburetor

The main jet size is of great importance when operating at considerably varying altitudes for which the following rule-of-thumb may be applied: Change main jet size by 60/0 for each, 1,OOO m (3.280 ft) altitude variation, For example, normal jet size at an altitude of 400 m (1,312 ft) is 0120; proper jet size for an altitude of 1,400 m (4.592 ft) is 0115.

254

2.3 REPAIR PROCEDURES

2.3.1 Removing and Installing Fuel Line

1. Remove both air cleaners. 2. Detach fuel line from both carburetors by removing connectors. 3. Remove attaching clip from air blower housing. 4. Withdraw fuel hose from fuel pump.

Reassemble in reversed order of the above using new gasket and attaching the fuel line so it does not touch the housing to ca use rattles.

255

2.3.2 Removing and Installing Carburetor

Removal

1. Unsnap air cleaner fasteners. 2. Remove air cleaner. 3. Remove air cleaner base plate. 4. Detach carburetor linkage from throttle arm. 5. Detach fuel line. 6. Remove four carburetor retaining nuts from carburetor flange. 7. Withdraw carburetor. 8. Cover intake duct.

Installation Install in reversed order of the above, making sure that the gaskets seat well and the linkage does not bind.

Changing Air Cleaner Cartridge (KNECHT -Filter)

1. Remove center screw from filter housing top and pull out. 2. Withdraw filter housing top by pulling up. 3. Replace cartridge.

Reassembly

Inspect square plastic foam gasket, replace if necessary.

256

2.3.3 Cleaning Carburetor

1. Remove carburetor. 2. Wash carburetor with clean solvent. 3. Remove retaining screws from carburetor cover. 4. Withdraw carburetor cover, watch float pin retainers. 5. Remove float pin and float. 6. Remove main, idle, and pump jets. 7. Remove air correction jets and shake out emulsion tubes. 8. Remove power enrichment and idle air bleed jets. 9. Remove float needle valve assembly. 10. Clean all jets and ports 11. Reassemble carburetor.

The carburetor should be cleaned in a utensil containing clean solvent. All jets and ports should be cleared with compressed air. In no case should wire or other mechanical devices be used for cleaning the jets because the calibrated orifices can be damaged or enlarged.

257

2.3.4 Disassembling and Reassembling Carburetor

1. Remove carburetor 2. Remove retaining screws from carburetor cover, withdraw cover with

gasket. 3. Remove float with pin and intermediate swivel joint. 4. Remove four accelerating pump retaining screws and remove pump. 5. Remove main jet carrier with jets. 6. Remove idle air bleed and idle jets. 7. Remove air correction jets and shake out emulsion tubes. 8. Remove injection nozzle retaining screws and carefully withdraw the

nozzles making certain that nozzles are not bent in the process. 9. Remove both pump jets and accelerating pump check valve. 10. Remove power enrichment jets. 11. Remove idle mixture adjusting screws.

12. Loosen preatomizer set screws. 13. Pull out preatomizers by first freeing with a gentle twist. 14. Loosen and remove venturi set screws. 15. Pull out venturis by first freeing with a gentle twist and then

carefully lifting these out, making sure they do not bind. 16. Remove burrs in venturi which were caused by set screw pressure.

258

2.3.5 Inspection and Reassembly

Reassemble in reversed order of the above by noting the following points:

1. Check float needle valve and seat for wear (leak test). 2. Fuel line connector threads in cover must not be damaged. 3. Check condition of gaskets, replace if necessary. 4. Ensure that accelerating pump diaphragm is in good condition. 5. Check float for leaks, replace of defective. 6. Ensure that all jets are of proper size by comparing specifications on

page F 11. When replacing jets or check valves, ensure that only genuine SOLEX-stamped parts are used. The parts are carefully calibrated to permit precise settings and low fuel consumption.

7. Install venturis. When installing the venturis make certain that the venturi throats face up. that is, the writing on the venturi tubes should be seen from above. Firmly tighten venturi set screws but do not overtighten.

8. Check radial clearance of throttle shaft. Excessive clearance allows false air to pass through and impairs engine starting and idling. .

9. Inspect idle mixture adjusting screws; bent, burred, or broken needle tips call for replacement of the screw,

259

2.3.6 Adjusting Injection Quantity

Special Tools: P 25a Calibrated Vial

Adjustments

1. Adjusting idle speed. 2. Run engine to fill float chamber with fuel. 3. Stop engine, remove both air cleaners. 4. Work throttle arm until air bubbles cease to show at the pump injection

nozzle.

5. Hold calibrated vial (P 25a) at the tip of the nozzle and quickly move throttle arm two times from stop to stop.

6. Check injection quantity, empty the calibrated vial, repeat procedure on the second, injection nozzle.

7. Injection quantity from each nozzle on two pump strokes should be 0.45 cc (7.3 minimum) during the warm season, and O. 65 cc (10.6 minimum) during the cold season.

8. Check injection quantity in second throat. 9. If required, readjust injection quantity by resetting the adjusting nut on

the pump rod. If adjustment should not be possible due to lack of threads, insert a spacer between the pump arm and the nut.

260

Note Fuel squirting from the pump nozzle should not strike the pre-atomizer nor the venturi and must pass through the slit between carburetor wall and throttle valve,

1. Injection nozzle 2. Pre-atomizer 3. Venturi 4. Carburetor body 5. Squirting fuel 6. Throttle valve

Should it become necessary to bend the injection nozzle, insure that its tip remains at same height. The pump jet does not affect the injection quantity. Changes in size of the pump jet affect only the duration of injection since the jet size controls the flow only in respect to flow duration. Injection quantity as well as the moment of injection must be identical in all carburetor throats.

261

2.3.7 Adjusting Idle Speed

Special Tools: P 227 Carburetor Synchronizer

Adjustments

1. Remove idle mixture adjusting screws and inspect needle tips for burrs, grooves, and bends. Install new screws if in doubt,

2. Bring engine to normal operating temperature and remove air cleaners. 3. Detach throttle rods from throttle arms. 4. Uniformly turn idle adjusting screws in until engine idles at about 1,000

rpm. 5. Following any convenient sequence turn idle mixture screws fully in on

both carburetors - do not tighten since this can damage the needle points - then back off 1 1/2 turns. From this position turn the screws in or out until fastest idling speed is achieved, In no case should the screws be left in fully turned-in position.

6. Adjust idle speed screws until the engine idling rpm drops to 800 - 900.

262

7. Place carburetor synchronizer (P 277) on carburetor throat and adjust plunger glass to vertical position.

8. Turn adjusting disc in synchronizer until plunger moves to about half-way between two marking rings about midway of the glass tube length; this accomplished, the synchronizer is set for the particular engine and no further adjustments should be made with the disc in the synchronizer.

9. Place synchronizer (P 277) onto second throat of the carburetor assembly; the plunger should move up to same point as during procedure described above. If the reading is different, the throttle valves are not in alignment and must be synchronized, which is easily accomplished by twisting the throttle shaft. Using the synchronizer, recheck synchronization of both throttle valves by comparing readings of the synchronizer when placed first on one, then on the other throat.

10. Without changing synchronizer adjustment. place synchronizer onto throats of second carburetor assembly and adjust throttle valve with idle speed screw so that the plunger in synchronizer moves to same height as observed during test described in Pt. 9, above readjust throttle valve if necessary,

11. Should it be noted during the adjusting procedure that the idle speed has changed, readjust idle speed screw settings and recheck carburetor synchronization with the synchronizer, correct of necessary.

12. Reconnect throttle rods to throttle arms. NOTE ! Adjust carburetor rods so that these can be attached to the carburetor arms without preload in relation to each other.

13. Set idling speed to 1,200 - 1,300 rpm. Using the synchronizer (P 227) recheck synchronization of all throats as described in Pts. 8 and 9. If the gauge does not show equal values in both carburetors, synchronize these with each other by properly adjusting the carburetor throttle rods.

14. Recheck idle speed. 15. Check injection quantity (warm season 0.45 cc from each nozzle on

two pump strokes, 0,65 cc in cold season). 16. Check accelerator pedal stop bolt and adjust if necessary. When

the accelerator pedal is depressed against the stop bolt, the carburetor arm should be clearing the carburetor stop block by about 1 mm (.039 in).

17. Install air cleaners with gaskets, tighten retaining screws.

263

2.3.8 Checking Carburetor Float Level

Special Tools: Special Tools: P 78 Float Level Gauge

Procedure 1. Place car on level base. 2. Remove main jet carrier from one carburetor.

3. Install float level gauge (P 78) in place of main jet carrier. 4. Start engine and allow to idle. When float level is correctly set, the fuel will rise to a point between the marking rings on the gauge tube. If the fuel level check is accomplished according to the above instructions, the need for a float level readjustment will seldom occur. Whenever the float level deviates from specifications, first check the float, float adjustment swivel, and the float needle valve; thereupon proceed with steps required for readjusting the float level by resetting the externally located float level adjusting screw. Note : Turn adjusting screw in to lower the fuel level, turn the screw out to raise the level. Apply the following procedure if the float level gauge (P 78) is not at hand: 1. Place car on level base. 2. Start engine,

264

3, Remove plug from the float level inspection port, When the float level is correct, the fuel will be seen in the machined groove within the threaded part of the port, or it will just begin to flow out. 4. Readjust float level if necessary. Note : Turn adjusting screw to lower the float level, turn the screw out to raise the level, Note Turning the adjustment screw in causes the float to move downward which, in turn, causes some of the fuel to run out through the inspection port. Therefore, allow the engine to use up the fuel excess before making the final adjustment.

265

2.3.9 Removing and Installing Air Cleaners

1. Detach carburetor heating hose, 2. Unsnap all four fasteners at the lower part of the air cleaner housing

(KNECHT-Filter), 3. Detach crankcase breather hose from the air cleaner housing. 4. Withdraw the air cleaner housing upward (KNECHT-Filter). Remove five

retaining bolts at forward air duct box and remove box (MANN and HUMMEL Filter).

5. Remove retaining bolts from air cleaner base plate and remove plate (KNECHT-Filter).

Installation

Install air cleaner in reversed order of the above, ensuring that the gasket sealing surfaces are clean; use new gaskets if necessary.

266

2.3.10 Removing and Installing Intake Duct

Remove

1. Remove carburetor. 2. Remove spark plug connectors from spark plugs. 3. Remove side cover plate. 4. Remove retaining nuts and bolt from intake duct and withdraw duct. 5. Cover intake port in cylinder head.

Installation Install intake duct by noting the following points:

1. Use new intake duct gasket. Make sure that the gasket matches the contours of the intake port in cylinder head.

2. Place the graphite-coated side of the gasket towards the cylinder head. 3. Inspect intake duct for cracks. 4. Carefully and evenly tighten the intake duct retaining nuts and bolt. 5. Install new gasket between duct and carburetor .

2.3.11 Removing and Installing Throttle Linkage

Remove

1. Remove floor mat to gain access to opening in floorboard. 2. Detach throttle rod at ball joint of cross-shaft at air blower housing. 3. Remove gearshift lever base retaining screw (hex head). 4. Withdraw gearshift lever with base. 5. Remove handbrake lever with base. 6. Remove attaching clip of throttle rod through freed openings. 7. Detach throttle rod from rear cross-shaft ball joint joint (beneath

transmission). 8. Pulling rearward, withdraw throttle rod.

Installation

Note the following during installation: The ball joints and all moving joints of the cross-shafts should be well lubricated. Ball joint lock nuts must be well tightened.

267

2.3.12 Adjusting Throttle Linkage

The throttle linkage must be so adjusted that all throttle valves work in unison. In addition it should be noted that the throttles do not bind throughout the entire extent of travel from idle to full power settings.

Note

Smooth and even clowing action of the throttles can be achieved only when all throttle linkage ball joints move freely. Lubricate the ball joints if necessary.

2.3.13 Carburetor Service Diagnosis

Chart The chart applies only to carburetors which meet specifications shown on page F 11.

Malfunction Possible Cause Remedy

1. Engine does not start despite properly functioning ignition and adequate fuel in tank.

a) No fuel in fuel system.

a) Clean main jets. Check fuel supply lines. Detach fuel line connecting pump with carburetor, actuate starter (ignition off). If fuel flows from pump, float needle valve is plugged; if no fuel flows from pump, possibly pump check valves are stuck or pump mechanism defective.

b) Carburetor floods.

b) Check and clean float needle valve, check gasket at float needle valve assembly. Check float, replace if defective. </TD< tr>

2. Uneven idling. a) Improperly adjusted idling.

a) Readjust idling.

b) Idle jets or idle air bleed plugged.

b) Clean idle jets or idle air bleed, as required.

c) Leak in the intake ducts.

c) Check intake ducts, flange connections, and gaskets.

d) Defective idle mixture screws.

d) Install new idle mixture adjusting screws.

268

3. Poor power transition (flat spot).

a) Idle adjustment too lean.

a) Readjust idling (check jets).

b) Improperly set float level.

b) Readjust float level.

c) Improper injection quantity.

c) Readjust injection quantity.

d) Intake ducts leaking.

d) Check intake ducts, flange connections, and gaskets.

4. Engine stalls when throttle is quickly closed.

Improper idle adjustment.

Readjust idling.

5. Engine runs unevenly, misses, backfires.

a) Mixture too rich.

a) Check fuel pump pressure. Check float level. Check float needle valve.

b) Mixture too lean.

b) Clean main jets. Check fuel lines. Check float level.

c) Intake duct leaking.

c) Check intake ducts, flange connections, and gaskets.

6. High fuel consumption.

a) High fuel pump pressure overriding float needle valve.

a) Check fuel pressure.

b) Defective float (leaking).

b) install new float.

c) Float needle valve not closing.

c) Check float needle valve.

269

2.4 FUEL PUMP

2.4.1 Fuel Pump Schematic

1. Fuel screen 2. Outlet valve 3. Upper assembly 4. Lower assembly 5. Oil scraper 6. Actuating plunger 7. Pump cover 8. Inlet valve 9. Diaphragm spring 10. Plunger return spring 11. Spring retainer

270

General The fuel is pumped to the carburetors by a mechanical diaphragm pump which is mounted on the engine crankcase. The fuel pump is actuated by an eccentric machined into the distributor pinion shaft. The quantity of fuel delivered by the pump is metered automatically in direct proportions to the amount of fuel dispensed by the carburetors. The fuel pump consists of an upper and lower assembly. The upper assembly accommodates an inlet and outlet valve, and a fuel filter. The lower assembly contains the actuating plunger. Located between both assemblies is a diaphragm and diaphragm spring. The diaphragm is built up of several layers of a fuel-proof material, and is sandwiched between two supporting discs which are riveted to the plunger coupling; the diaphragm also acts as a gasket.

Function Description

The eccentric on the pinion shaft raises the diaphragm actuating plunger. The plunger transmits the pressure to the diaphragm coupling, overcoming the pressure of the plunger return spring but with the support of the diaphragm spring. This forces the fuel contained in the pump to exit through the outlet valve on to the carburetors. When the actuating plunger moves back with further rotation of the eccentric, negative pressure is created in the chamber above the pump diaphragm and fresh fuel enters the pump through the inlet valve. This pumping action repeats with every revolution of the eccentric (once every two revolutions of the crankshaft). The amount of fuel passing through the pump is governed by the amount dispensed by the carburetors; that is, only that amount of fuel can be pumped which is able to pass through the more or less opened float needle valves in the carburetors.

271

2.4.2 Schematic of Manual Fuel Pump Drive

1. Fuel pump 2. Pump insulating flange 3. 0 -ring 4. Actuating plunger 5. Distributor pinion shaft

272

2.4.3 Pump Side of Mechanical Fuel Pump

1. Hex bolt 2. Gasket 3. Cover 4. Gasket 5. Fuel screen 6. Pump, upper assembly 7. Leaf spring valve 8. Valve limiter 9. Self-threading screw M 3x8 10. Fillister screw with washer

273

2.4.4 Actuating Side of Mechanical Fuel Pump

1. Diaphragm assembly 2. Coupling pin 3. Plunger 4. Diaphragm spring 5. Pump, lower assembly 6. Plunger return spring 7. Spring retainer 8. Lock ring.

274

2.4.5 Testing Pump Pressure

General The pump pressure is determined by the degree of spring compression during the intake stroke of the pump. The spring tension is so calibrated that it allows,the fuel to enter the carburetor only as long as the float needle valve is open. When the buoyancy of the float forces the float needle valve to close, pressure builds up in the fuel line and pump fuel chamber shortening the pump stroke. In normal operation, the diaphragm stroke amounts to only a few tenths of a millimeter. The lower assembly is vented through two orifices in the casting. Also, should the fuel leak into this part of the pump, it can drain through the venting holes.

Testing

The pump pressure should be 0.20 to 0.24 atmospheres (2.9 - 3.5 psi) with the float needle valve closed and engine running at 1,000 - 3,000 rpm. Minimum fuel delivery should be 30 liters (7.9 US gal.) per hour, which equals 500 cc (16.9 us f1. oz.) per minute, at 4,500 rpm. The simplest way to check the fuel pump pressure is with the aid of a pressure gauge inserted into the fuel line between the pump and carburetor by means of a T-joint. A fuel shut-off valve is incorporated in the fuel line behind the pressure gauge. Essential for proper pump pressure is correct spring tension and faultless condition of the diaphragm and control valves. Excessive pump pressure causes carburetor flooding and, in almost all cases, leads to dilution of oil. Insufficient pump pressure causes lean combustion mixture and, thus, a rough running engine with misfiring at high rpm and decreased power output.

275

2.4.6 Removing and Installing Fuel Pump

Removal

1. Remove fuel hoses from pump. 2. Remove pump shield.

276

3. Remove pump attaching nuts from flange.

4. Remove pump and insulating spacer.

Installation

Installation is accomplished in reversed order of the above. Ensure that the O-ring is in good condition, replace if necessary.

277

2.4.7 Reconditioning Fuel Pump

Disassembly

1. Remove cover retaining hex bolt. 2. Remove cover and fuel screen.

3. Remove six fillister screws which secure the upper assembly, withdraw assembly.

278

4. Rest the lower assembly of pump on the diaphragm supporting disc, push spring retainer down with pliers, remove lock ring, spring retainer, and spring.

5. Withdraw the diaphragm-plunger-spring assembly from lower pump casting. Ensure that there is no grit around the lock ring groove in plunger to prevent damaging the oil scraper.

6. Remove coupling pin from actuating plunger with a punch, detach diaphragm from plunger.

279

7. Remove self-threading fillister screw from inlet valve and remove leaf spring valve and valve limiter (outlet valve cannot be removed).

8. Clean pump components with gasoline.

Reassembly Reassembly is accomplished in reversed order of the above by noting the following points:

1. Check outlet valve in upper assembly for proper functioning. 2. Check sealing surfaces of inlet valve. 3. Install leaf spring valve and valve limiter, check for proper operation. 4. Reconnect diaphragm with plunger with the pin, check free movement of

plunger in diaphragm coupling. Center coupling pin in plunger. 5. When mounting pump upper assembly. ensure that the diaphragm is not

creased. Evenly tighten screws in cross-sequence. 6. Check gasket at pump cover, replace if necessary.

280

3. Electrical System 3.1 ELECTRICAL SYSTEM DESCRIPTION

Generator A 12 volt, 300 watt generator is utilized, The alternator charges the battery and supplies current to the electrical units of the car.

Engine Starter An 8/10 HP - solenoid-operated starter is utilized. The starter is controlled by the ignition/starter switch on the instrument panel.

Battery The six-cell, 12 volt, 45 Ah battery is located within the luggage compartment under the front lid. The negative battery terminal is connected to the ground.

Ignition System The ignition system is battery operated and includes a high tension coil as well as a distributor which is equipped with a centrifugal spark advance mechanism. The distributor is driven by a worm gear mounted on the crankshaft, The ignition current is switched on through the ignition switch on the instrument panel.

Lighting The two headlamps are mounted in the front fenders and have high and low beams in each. Parking lights are accommodated in the front directional blinker housings. The parking lights and headlights are switched on through a switch on the instrument panel, next to the ignition switch, Instrument light brightness can be varied with the light switch knob by turning it to the desired position, Tail lights go on with headlights. The headlights are dimmed with the blinker/dimmer/headlamp flasher switch located on the steering post below the steering wheel. A blue headlamps control light goes on in the tachometer dial when high beams are on, The two tail lights are combined with stop lights and directional blinkers, Two small lamps illuminate the license plate in the back, The stop lights are controlled through a switch mounted in the brake master cylinder and go on when the foot brake is depressed, The backup lights go on when reverse gear is engaged; the lamps are located in the tail lamp housing, the switch in the side of the transmission housing. The interior lamps are located above the doors, The lamps can be turned on by tilting the entire lens. In the same manner, the lamps can be set for courtesy operating together with the opening doors.

281

The cigar lighter socket in the instrument panel can also be used for plugging in a hand lamp.

Electrical Accessories The signal horns can be sounded through a horn button in the center of the steering wheel; the contact is made through a contact ring in the blinker/dimmer/flasher switch. The directional blinkers and head lamp signal flasher can be actuated through switch lever in the steering post extension; the switch also controls the high and low head lamp beams. Operation of the directional blinkers is indicated by a green control light in the tachometer dial as well as through an audible ticking noise in unison with the flasher. The windshield wipers and washers are actuated through a combination wiper/washer switch on the steering post. The fuses for the various accessories are located in the left part of the luggage compartment and are covered with a plastic top.

Instruments The speedometer and odometer are driven by a gear in the transmission by means of a cable drive. The tachometer is transistorized; electrical pulses emanating from the ignition system pass through a transistorized con venter and are fed into an electric counter in the tachometer unit. The fuel level is indicated by means of a fuel gauge which is connected to an electrical sending unit in the fuel tank. In addition, the gauge has a low fuel warning light.

Note Repairs in the electrical system normally are confined to the replacement of worn or defective parts and the repair of the wiring system. In general, damaged wiring removed from the system should be replaced wire of same cross-section as shown in the wiring diagram. BOSCH components should be repaired by BOSCH service whenever possible.

Caution

To avoid shorting the circuit and minimize fire hazards due to electrical sparks, the battery ground strap should be removed from the battery prior to the initiation of any work in the electrical system.

282

3.2 LAMPS AND FUSES

1. High beam, left 2. High beam, right High beam indicator 3. Low beam, left 4. Low beam, right 5. Parking lamp, left 6. Parking lamp, right 7. License plate lamp and luggage compartment lamp 8. Fog lamps 9. Windshield wipers and washer 10. Auxiliary combustion heater 11. Interior light, cigar lighter, electric clock 12. Stop lights, blinkers, backup light

283

Bulb Chart All bulbs 12 volts

Qty Nomenclature Wattage

2 Twin filiament headlamp bulbs 45/40 W

2 Sealed beam inserts (US made) 50/40 W

4 Cartridge bulbs for parking and license plate lamps 4W

2 Cartridge bulbs for parking lamps (Italy) 3W

4 Single filiament bulbs for directional blinkers 18 W

4 Single filiament bulbs for directional blinkers (Italy) 15 W

(6) Single filiament bulbs for directional blinkers and backup lights (USA)

32 cp

(2) Twin filiament bulbs for stop and taillights (USA) 32/4 cp

2 Twin filiament bulbs for stop and taillights 18/5 W

2 Single filiament bulbs for backup lights 25 W

2 Cartridge bulbs for interior lights 10 W

1 Single filiament bulb for luggage compartment light 5W . 16 Bulbs for instrument illumination and control lamps

2W

(2) Single filiament bulbs for parking lights (USA) 2 cp

284

3.3 GENERATOR DESCRIPTION

General The generator has the function of supplying all the current consuming units in the vehicle and to charge the battery satisfactorily. It is driven by the engine by means of a V-belt. To regulate the voltage which varies according to the loading of the generator by the current consumers or by the varying speed of the engine there is a toggle regulator with a sloping characteristic curve.

Method of operation The generator is a DC shunt-wound machine. Its voltage is maintained at approximately the same level by means of a electro-magnetic high speed regulator independently of engine speed and loading. In addition this regulator prevents overloading of the battery. An electro-magnetic switch switches the generator on automatically and at low speeds disconnects it from the battery so that discharge of the battery through the generator is prevented. Regulator and switch are combined to form a regulator switch. In order to protect the generator from overloads resulting from the very high charging current occurring when current consumers are switched on the battery is flat and the voltage constant, regulators with output limitation are used.

Variode regulator The variode regulator fitted in the vehicle has on the voltage regulator unit a second winding (control winding). This is connected on one side to the switch contact and on the other side via the variode (semiconductor unit) to D+. When current flows through the main current lead a potential drop arises between D+ and the switch contact. When the output limit of the generator is reached the variode becomes conductive as a result of the potential drop. In the, control winding flows a current which strengthens the magnetic field on the voltage regulator unit and thus reduces the generator potential. The generator is thus protected against overload.

Construction of generator The main components of a generator are: The pole housing with pole shoes and the exciter, winding the armature with armature winding and commutator the carbon brushes and brush holders the bearing cap (drive bearing and commutator bearing) the special regulator switch The pole housing is a hollow cylinder of special iron which forms a very good conductor for the magnetic flux. The pole shoes are fixed on the inside of the housing by means of countersunk bolts into the housing.

285

On the pole shoes are located exciter coils connected in series which consist of a large number of windings of insulated copper wire. Between the pole shoes rotates the armature, an iron core in which are bedded the windings (armature conductors) of the armature coil and on whose shaft is also fitted the commutator (current reversal switch) from which the induced generator potential is collected. The iron core of the armature is made up of a large number of thin stamped out metal plates which are insulated from each other for suppression of eddy currents. The armature coils which consist of a fairly large number of windings of insulated copper wire are located and insulated in the grooves of the armature. The armature conductors are protected against centrifugal throw-out. The total number of all the coils is called the armature winding which consists of as many coils as the commutator has segments, To ensure that all commutator coils are conductively connected to each other and thus always contribute collectively to the production of the generator potential the end of one coil is soldered into one of the commutator segments with the beginning of the next coil. Thus a closed circuit armature winding is effected. The commutator consists of copper segments which are insulated from each other and from the armature shaft. The insulators between the individual segments must be recessed back from the commutator surface so that the carbon brushes will only run on the copper even after a considerable period of operation. The carbon brushes are pressed against the commutator under uniform spring pressure and collect the current produced in the armature coils. The carbon brushes locate in box shaped brush holders. The armature shaft is mounted in ball bearings on both sides. Both the bearing caps, that of the drive bearing and the commutator bearing seal off the pole housing from outside. The commutator bearing is covered by a cover strip so that the generator will be easily accessible for servicing of the carbon brushes and the commutator.

286

Maintenance

The ball bearings in the generator are packed with ball bearing grease (e. g. Bosch FT IV 33) and normally require no attention. Repacking with grease, which under no circumstances should be done with normal lubricating grease, will normally only take place during the course of an engine overhaul.

Approximately every 10,000 km (6000 miles) the cover strap should be opened and the carbon brushes checked for wear and free travel. Used brushes should be replaced. The carbon brushes should not be oiled.

287

3.3.1 Changing Ignition Warning Light

General The ignition warning light (red) is connected between the B+ terminal and 61 of the regulator switch of the generator and lights up in the combination instrument on the instrument panel when the ignition is switched on. After starting the engine the light will go out as soon as the increasing charge voltage of the generator is equal to the battery voltage.

Testing Switch on ignition, the ignition warning light dh the instrument panel must light up. Undo generator cable from terminal D+ 61 on regulator, the light must go out. If this is.not the case the cable is shorting to earth and this fault must be rectified. Reconnect cable to terminal D+ 61, The light serves at the same time as a check on the V-belt and thus also on the cooling fan. If the V-belt breaks the generator and fan will remain stationary and the light will come on.

Changing the bulb

1. Pull out bulb with holder. 2. Push bulb slightly into holder rotate slightly and withdraw. 3. Fit new bulb in reverse order.

288

3.3.2 Checking the Generator

Remark For checking the electrical system the following test instruments are required: One Voltmeter range 0 - 20 Volts

1. One voltmeter range 0 - 20 Volts. 2. One ammeter range 10 - 0 - 60 Amps. 3. Load resistance (adjustable) of 500 Watts nominal capacity.

Note Extinguishing of the ignition warning light after starting and with increasing engine speed gives no guarantee for charging of the battery. If the wiring system is in order incorrect charging of the battery, i.e. excessive or too little charging current, will be indicated by bad starting, weak headlamp illumination when starting at night. Abnormally high water requirement by the battery should lead one to suspect excessive charging current, checking can be carried out initially without removing the generator or having to uncover the regulator. In the first instance the condition and tension of the V-belt should be checked.

Regulator Voltage No Load

1. Undo battery lead from terminal B+ on regulator and temporarily insulate cable shoe. The positive lead of the voltmeter should be connected to termianl "D+ / 61" and the negative lead to earth.

2. Start the engine and run the generator up to double the rated speed, the voltmeter must then show the correct regulator voltage. If the prescribed voltage is not reached generator and regulator should be overhauled.

Regulator voltage on load

289

1. Connections as in Fig. 5 but the A. M. should be connected in series with the control resistor between terminal B+ on regulator and earth.

2. Start engine, increase speed up to generator test speed and keep constant. Adjust resistor until the A. M. indicates the corresponding test voltage. At this setting the voltmeter must indicate at least 12 V with a generator in good condition.

3. If during this test the generator gives off no current it must be removed and repaired.

290

3.3.3 Removing and Refitting Regulator Switch

Removal

1. Disconnect battery. 2. Remove leads from regulator. 3. Undo fixing bolts and detach regula tor.

Refitting The following should be noted:

1. When exchanging the regulator first check that there is no short to earth in the field coils of the generator.

2. Connect cables as per wiring diagram on regulator housing. 3. Polarise generator (see 5 LI note). 4. If incorrect values are obtained even after fitment of a new regulator

either the generator or the wiring system is not in order and a Bosch service station should be contacted.

3.3.4 Checking Carbon Brushes and Commutator

1. Undo cover strap of generator. 2. Check carbon brushes for wear and free travel in the brush holder

guides. Brushes which completely disappear into the brush holder are worn and must be replaced; the same applied to brushes which have become heavily oiled.

3. If the commutator is oily or greasy it can be cleaned with a clean cloth which has been soaked in petrol and wrapped round a piece of wood, When doing this care should be taken to ensure that no dirt gets into the ball bearing.

4. Check the pressure springs for tension (see electrical data) if necessary. replace defective springs.

5. If the commutator surface has become uneven as a result of running in of the brushes or has burn spots, it should be skimmed.

Note

Any petrol on the commutator should be allowed to evaporate completely before start-up (fire risk).

291

3.3.5 Removing and Refitting Generator

Removal

1. Disconnect cable at generator. 2. Detach V -belt. 3. Remove clamp strip of generator. 4. Undo fixing bolts on generator bracket. 5. Undo four bolts on fan cover and extract generator.

Refitting When refitting the following should be noted:

1. Ensure satisfactory condition of paper gasket on the generator bracket at the crankcase.

2. Reconnect leads in accordance with wiring diagram.

Note:

Before fitment of the V -belt the generator should always be polarized to prevent any damage to the regulator and to ensure correct charging, For this purpose one should connect the battery lead for a short time to the terminal 61 D+ on the regulator, The generator must now start to run as an electric motor i,e. in the direction of rotation of the engine.

3.3.6Dismantling and Reassembling Generator

Dismantling

1. Detach V-belt pulley and cooling fan. 2. Undo field coil connection from brush holder of positive brush. 3. Undo both generator housing bolts. 4. Take generator housing apart and extract armature. 5. Pull out ball bearings, After dismantling individual parts wash carefully in

petrol and blow through with compressed air.

Reassembling Reassembly should be effected in the reverse order observing the following points:

1. Check armature, field coils, cable connections and brushes, 2. Check ball bearings for wear and damage and replace if necessary. Wash

bearings carefully in petrol and pack with Bosch grease Ft 1 V 33. 3. Ensure correct connection of leads to brush holders,

292

3.3.7Checking Armature

Armature faults are in many cases not externally visible. Checking should include tracing of open circuits as well as winding and earth shorts.

1. Open circuits are generally recognizable on the commutator by burn spots between two segments. They can also be measured with a sensitive resistance measuring bridge. 2. Winding short circuits between windings of an armature coil can be traced on an armature test meter. The armature is rotated between two test probes, a magic eye then indicates the winding short circuit. Another instrument consists of an AC magnet with two jaws which take the armature. Here the armature is slowly rotated about its axis a thin piece of steel sheet being placed on top of the armature. If there is a short circuit in the winding the sheet of metal will begin to vibrate violently at 2 or more places around the periphery of the armature. With another instrument the armature is rotated in the same way over the jaws of an AC magnet while the tester probes the commutator core with a probe. The alternating current produced in the coil of the probe as a result of induction from a winding short circuit can be heard in the test head phones as a humming noise.

293

3. A short to earth will occur if the armature core is shorted to the winding or if carbon dust ha s penetrated into the winding. The test should be carried out with a test lamp of 40 V between armature iron and commutator. The test lamp should not light up. 4. If the commutator is oval or is rough as a result of burn spots or grooves have occurred as a result of running in of the carbon brushes it must be skimmed and polished which is essential to obtain a satisfactory surface. The insulators between the segments should be reworked with a commutator saw until they are recessed back about 0.3-0.5 mm from the contact face of the commutator.

294

Both field coils should be checked for open circuit, winding and earth shorts.

1. Check each field coil separately for open circuit connecting its ends with a 12 V test lamp in series with the battery. In the case of open circuit the test lamp will not light up.

2. Winding shorts can be checked by connecting the ohmmeter with the ends of each coil and comparing the test result with the recommended values (see electrical data). If an ohmmeter is not available one should connect a 12 V battery in series with an ammeter to the coil ends and should then compare the current intensity at the coils, If the current consumption difference between the two coils is greater than 0,5 Amps, the coil with the higher reading has a short circuit.

3. One should check the coils for short circuit to earth by connecting a 40 V test lamp to one end of the field coil and the generator housing. The test lamp should not light up.

4. The field coils should also be checked for satisfactory electrical and mechanical contact with each other.

295

3.3.8 Generator Faults and their Elimination

The red ignition warning light on the combination instrument should light up when the ignition is switched on and should go out after the engine has started and the engine speed has begun to rise. The possible causes of trouble are summarised below:

Fault Cause Remedy

Warning light does not come on when ignition is switched on

a. Battery flat a. Charge up battery

b. Battery defective b. Renew battery

c. Bulb burned out c. Renew bulb

d. Battery terminal corroded or loose

d. Clean connections and if necessary tighten up

e. Cable loose or broken

e. Tighten cable or repair

f. Ignition switch defective

f. Renew ignition switch

g. Generator brushes are not running on commutator

g.Free carbon brushes or renew or replace pressure springs. Do not oil carbon brushes!

Ignition warning light does not goout when engine speed rises or flickers, glows

a. V -belt loose or defective

a. Tighten or renew belt

b. Regulator switch defective

b, Exchange regulator switch

c. Charging lead loose or broken

c. Check cables and connections

d. Generator defective

d. Check generator

e. Ignition switch lead has bad connection

e. Tighten connections

Ignition warning light only goes out at high engine speeds

a. Generator defective

a. Check generator, repair

b. Regulator switch defective

b. Exchange regulator switch

Ignition warning light a. Short to earth in a. Eliminate earth short

296

continues to burn after ignition switched off

cable or warning light

3.4 Engine Starter Description

General

The purpose of the starter is to start the engine, Type 911 and 912 cars are equipped with a starter of 0,8 HP rating, designed for 12 V systems. The starter has a helical spline drive with a self-releasing pinion (BOSCH Type EB). As in most cases, the starter is a DC motor. It provides a considerable amount of torque needed for turning the crankshaft at speeds needed for starting the engine and with enough force to overcome the initial resistance on the compression stroke. To obtain the necessary torque from a starter and battery of proportionately acceptable size, the starter drives the starter ring on the flywheel with a small pinion. The gear teeth in the starter ring and starter pinion are beveled on one side to make engagement smoother,

297

Due to the high gear reduction ratio between the starter ring and pinion, the pinion cannot remain engaged with the starter ring longer than necessary since the armature would be forced to spin at excessively high revolutions. Therefore, the connection between the armature and starter ring must be automatically interrupted as soon as the engine has fired up. In the BOSCH helical spline starters the interruption is accomplished by means of an overrunning clutch situated between the pinion and armature. The clutch breaks the connection as soon as the engine speed becomes higher than that of the starter. A coupling, which rides on the helical spline shaft of the armature, is connected with the pinion through the overrunning clutch. Located on the coupling is an actuating sleeve which can slide back and forth. A fork-shaped end of the actuating lever is constantly engaged in the actuating sleeve. The actuating lever moves the locking ring forward. Balls located in the coupling bores are freed and the pinion is free to move towards the engagement phase. When moving forward, the pinion rotates on the helical splines. The application of thrust and rotation prompted the designation as helical spline starter.

Operation

When the starter/ ignition key is switched on for starting, the starter solenoid is energized, The actuating lever pushes the actuating sleeve and the locking ring against the engagement ring; through this action, the engagement spring is tensioned, When the locking ring has moved forward by about 1/8 in. (2 -3 mm), the balls located in the bores of the coupling are freed and can slide out of the shaft groove into the enlarged part of the locking ring. Thus the engagement components are freed and the fork begins to move the pinion; being mechanically connected to the helical splines, the pinion "bores" itself with a turning motion into the teeth in the starter ring on the flywheel. A t this time, the switch in the solenoid closes and, simultaneously, energizes the main field windings, causing the armature to turn. As the armature proceeds to turn, the effect of the helical splines further presses the pinion into the starter ring up to the point where the balls come to rest against the flanks of the helical spline portion on the armature shaft. The actuating lever, also mechanically connected to the engagement

298

components, is dragged along in the forward direction and tensions the disengagement spring located on the drag link of the solenoid switch. If, for instance, the pinion should be stuck due to gear tooth pressure in cases where the engine fails to fire up, the disengagement spring makes the solenoid plunger move back enough to open the switch contacts when the starter switch is released. As a result, the starter is deenergized, gear tooth pressure ceases, and the pinion is drawn back through spring tension. Normally, the pinion leaves the starter ring when the starter switch is released due to spring force exerted by the solenoid return spring which travels the distance allowed by the disengagement spring. This occurrence is further supported by the fact that the overrun clutch breaks the torque transmitting connection between the pinion and armature shaft when the engine begins to turn faster than the armature. This also protects the armature from over-speeding. Under the pressure of the engagement spring, the balls return into their groove in the shaft. The engagement spring decompresses further and pushes the locking ring over the balls. The brake disc is pressed against the brake pot of the armature and, at the same time, the balls in the coupling bores are pressed against the edge of the resting groove in the armature shaft. The decelerating armature is thus braked under the pressure of the engagement spring, further supported in this by the solenoid return spring.

299

4. Rear Axle and Transmission

4.1 ADJUSTING GEARSHIFT LINKAGE

4.1.1 Remove Cover

• 1. Remove retaining screws from cover in rear of center tunnel and withdraw cover.

4.1.2 Loosen Hex Bolt

• 2. Loosen hex bolt in shift rod clamp.

300

4.1.3 Set Selector

• 3. Move selector shaft of internal shift lever in transmission all the way left to stop while in neutral position. ("Right" or "Left" is in direction of travel)

• 4. With transmission in neutral, move the gearshift lever to the right to stop.

• 5. Tighten hex bolt of clamp to 2.5 mkp (18 lbs/ft). (Insert serrated washer under the hex nut).

• 6. Check adjustment by shifting all gears. Also check play in the gearshift linkage. (Gearshift level play should be the same in all gears in all directions).

original contents found at ... manual.pdf · 7 2. fuel system the fuel system consists of the...

Documents