bmw world - bmw m52 engine
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12/5/2014 BMW World - BMW M52 Engine
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The BMW M52 inline 6-cylinder engine was used in a variety of BMWmodels, including the E36 3 Series, the E39 5 Series Sedan, the Z3 and theE46 3 Series.
The M52 was an upgrade to the successful M50 engine. The M52 was producedin 2.0 (M52B20), 2.5 liter (M52B25) and 2.8 liter (M52B28) configurations.When the BMW E46 3 Series was launched in 1999, the M52TU engine wasintroduced in the E46 323i, E46 328i and the E39 528i models. The majorchanges in this Technical Update were the redesigned crankcase, modifiedpistons, Double VANOS for the camshaft drive, and Siemens MS42 DMEsystem. Later, the E39 523i was introduced with the M52B25TU engine.
BMW took a large step in 1994 with the introduction of an aluminum block with the wear-resistantNikasil coating on the cylinder bores. This reduced the engine's weight from around 190 kg (M50)to some 160 kg (M52). The camshafts were now fitted with counterbalancing masses, as wasalready the case on those of the eight-cylinder engine.
With the introduction of the M52 a new BMW power-output characteristic was introduced as well.The maximum power of 192 bhp previously achieved with the 2.5-liter engine was now reachedwith a 2.8 liter engine that delivered a significantly higher maximum torque. The new 2.5-literengine was positioned between the 2.0-liter and 2.8-liter versions with its 170 bhp.
As a special version for four countries with high-sulfur gasoline, the M52 was supplied with acast-iron cylinder block. The Nikasil cylinder coating would have had marginal reliability underthose operating conditions.
In 1998 the VANOS system, which initially adjusted only the inlet camshaft was developed intothe Double-VANOS system which now adjusted the timing of the exhaust camshaft as well. Thisopened the potential for further optimization of the engine's performance.
Double-VANOS system
The inlet system was provided with two technical refinements in 1998. One was a flap valve inthe inlet plenum chamber that cut off the inlet passages of the front three cylinders from the rear
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the inlet plenum chamber that cut off the inlet passages of the front three cylinders from the rearthree. The differentiated intake system, known as DISA, optimized the engine's running under fullload. The other refinement was a dedicated system of tubes of very small diameters throughwhich the inlet air was drawn during idling or when running at low loads. The increased turbulencethat this achieved improved the combustion process and thus reduced exhaust emissions.
In order to be able to offer a single cylinder block to all markets throughout the world, thealuminum block was given dry cast-iron liners.
source: Geschichte des Motors, Dr. Karlheinz Lange
Engine Specifications
Item/Measurement M52B20 M52B20 M52B25 M52B25
Vehicle 320i 320i 523i 323i
Number of Cylinders 6 6 6 6
Layout in-line in-line in-line in-line
Installation30 inclinedright
30 inclined right30 inclinedright
30 inclined right
Coolant liquid liquid liquid liquid
Crankcase/BlockMaterial
aluminum aluminum aluminum aluminum
Crankshaft one-piece one-piece one-piece one-piece
Main Bearings 7 7 7 7
Weight (kg) 166 177 166 177
Valve Layout dohc dohc dohc dohc
Camshaft Drive simplex chain simplex chain simplex chain simplex chain
Camshaft Bearings 7 each 7 each 7 each 7 each
Valves per Cylinder 4 4 4 4
Cylinder CenterDistance (mm)
91 91 91 91
Displacement (liters) 1.991 1.991 2.494 2.494
Bore/Stroke (mm) 80/66 80/66 84/75 84/75
Stroke/Bore Ratio 0.83 0.83 0.89 0.89
Piston Speed (ms) 13.0 13.0 13.8 13.8
Valve Timing (IO/IC) 4btdc/44abdc 6atdc/54abdc 4btdc/44abdc 6atdc/54abdc
(EO/EC) 39bbdc/9atdc 47bbdc/17atdc 39bbdc/9atdc 47bbdc/17atdc
At Valve Lift (mm) ER-ER ER-ER ER-ER ER-ER
Valve Lift I/E (mm) 9.0/9.0 9.0/9.0 9.0/9.0 9.0/9.0
Connecting RodLength (mm)
145 145 140 140
Connecting Rod Ratior/l
0.23 0.23 0.27 0.27
Compression Ratio 11.0:1 11.0:1 10.5:1 10.5:1
Fuel Norm-Sup Plus LF Norm-Sup Plus LF Norm-Sup Plus LF Norm-Sup Plus LF
Power Output(bhp@rpm)
150/5900 150/5900 170/5500 170/5500
Power per Liter(bhp/liter)
75.34 75.34 68.16 68.16
Power/Weight Ratio(kg/bhp)
1.11 1.18 0.98 1.04
Torque (mkg@rpm) 19.4/4200 19.4/3500 23/3950 23/3500
Torque per Liter(mkg/liter)
9.73 9.73 10.01 10.01
Mixture Preparation fuel injection fuel injection fuel injection fuel injection
Maker Siemens Siemens Siemens Siemens
Designation DME MS41.0 DME MS42.0 DME MS41.0 DME MS42.0
Ignition integrated integrated integrated integrated
Ignition Advance map map map map
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Ignition Advance map map map map
Generator 12 V/1120 W 12 V/1120 W 12 V/1260 W 12 V/1260 W
Supercharging - - - -
Miscellaneous VANOS, KD Double VANOS, KD VANOS, KD Double VANOS, KD
Year of Introduction 1994 1998 1995 1998
source: Geschichte des Motors, Dr. Karlheinz Lange
Engine Specifications, contd.
Item/Measurement M52B28 M52B28
Vehicle 328i 328i
Number of Cylinders 6 6
Layout in-line in-line
Installation30 inclinedright
30 inclined right
Coolant liquid liquid
Crankcase/Block Material aluminum aluminum
Crankshaft one-piece one-piece
Main Bearings 7 7
Weight (kg) 170 180
Valve Layout dohc dohc
Camshaft Drive simplex chain simplex chain
Camshaft Bearings 7 each 7 each
Valves per Cylinder 4 4
Cylinder Center Distance (mm) 91 91
Displacement (liters) 2.793 2.793
Bore/Stroke (mm) 84/84 84/84
Stroke/Bore Ratio 1.0 1.0
Piston Speed (ms) 14.8 15.4
Valve Timing (IO/IC) 1atdc/49abdc 6atdc/54abdc
(EO/EC) 39bbdc/9atdc 47bbdc/17atdc
At Valve Lift (mm) ER-ER ER-ER
Valve Lift I/E (mm) 9.0/9.0 9.0/9.0
Connecting Rod Length (mm) 135 135
Connecting Rod Ratio r/l 0.31 0.31
Compression Ratio 10.2:1 10.2:1
Fuel Norm-Sup Plus LF Norm-Sup Plus LF
Power Output (bhp@rpm) 193/5500 193/5500
Power per Liter (bhp/liter) 69.10 69.10
Power/Weight Ratio (kg/bhp) 0.88 0.93
Torque (mkg@rpm) 28.5/3950 28.5/3500
Torque per Liter (mkg/liter) 10.22 10.22
Mixture Preparation fuel injection fuel injection
Maker Siemens Siemens
Designation DME MS41.0 DME MS42.0
Ignition integrated integrated
Ignition Advance map map
Generator 12 V/1260 W 12 V/1260 W
Supercharging - -
Miscellaneous VANOS, KD Double VANOS, KD
Year of Introduction 1994 1998
source: Geschichte des Motors, Dr. Karlheinz Lange
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Links
Performance Parts for your BMW M52 engine.
Repair Tips to keep your BMW M52 in top shape.
BMW engine and model codes.
Engine Technology:
Valvetronic.
VANOS.
Engine Cleaning. Be careful with your BMW M52 engine.
Wallpaper of BMW engines. More...
More engine links.
Do not buy an M52 320/323/328 with an alloy block made before 3/98 unless it's had a newengine under warranty or you get a compression check done. Sulfur in fuel causes prematurebore wear which shows as a bad idle and lack of power. Only solution is a new block. - JohnG. Burns
John G. Burns E36 page has some tips for M52 engines.
Nikasil coating information.
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