All About MediuM- duty work truck

Eng inEsDefining exactly what a truck must do is the first step in spec’ing a medium-duty truck engine.

By Lauren Fletcher & Sean Lyden

10 WORK TRUCK JANUARY/FEBRUARY 2009 www.worktruckonline.com

Matching a medium-duty truck engine to a fleet ap-plication depends on the size truck needed. Here’s

a breakdown of what to consider when spec’ing engines for medium-duty trucks up to a 33,000-lb. gross vehi-cle weight rating (GVWR).

CLaSS 4 & 5 OptiOnSIf the truck you need is a Class 4 or 5 (14,001-lb. – 19,500-lb. GVWR), en-gine selection is relatively simple. In many cases, only one option is avail-able — diesel. Some manufacturers, such as Ford (F-450, F-550), GM (C-Series, W-Series), and Isuzu (N-Series, H-Series), offer both gasoline and die-

sel. Either way, you’re not overwhelmed with engine options.

How do you decide between gas and diesel on a Class 4 or 5? While diesel offers better fuel efficiency and engine longevity, gas engines have much lower up-front costs — a difference ranging anywhere from $6,500-$8,000 or more, depending on make and model.

Therefore, the key deciding factor is: How many miles per year will you be putting on that vehicle? Do you anticipate putting a substantial num-ber of miles to recoup the higher in-vestment in a diesel in a reasonable amount of time?

A general rule of thumb is 25,000-30,000 miles. If you project going over

that threshold, diesel makes sense. If you’ll be doing less, then gasoline may be more cost-effective.

Run the numbers yourself to con-firm what works best for you. Contact your manufacturer’s rep for approxi-mate fuel economy numbers for both gasoline and diesel to plug in your cal-culations.

CLaSS 6 & 7 OptiOnSIf you’re spec’ing a Class 6 or 7 truck, engine selection becomes more com-plicated. For example, the Isuzu Die-sel 6H 7.8L in the Chevrolet Kodiak C-7500 offers five different horsepow-er and torque options, ranging from 215 hp and 560 ft.-lb. torque to 300

■ ISL 345 & 365• 345 hp – 365 hp.• 1,150 ft.-lb. – 1,250 ft.-lb. torque.• 6-cyl., 9.0L.• Direct fuel injection.• Features: Enhanced high-pressure common rail fuel system. • Applications: Class 7-8.

■ ISc• 240 hp – 330 hp.• 660 ft.-lb. – 1,000 ft.-lb. torque.• 6-cyl. 8.3L.• Direct fuel injection.• Features: Enhanced high-pressure common rail fuel system. • Applications: Class 6-7.

■ ISB• 200 hp – 325 hp.• 520 ft.-lb. – 750 ft.-lb. torque.• 6-cyl. 6.7L.• Direct fuel injection.• Features: Enhanced high-pressure common rail fuel system.• Applications: Class 6-7.

cUMMINS

All About MediuM- duty work truck

Eng inEs

www.worktruckonline.com JANUARY/FEBRUARY 2009 WORK TRUCK 11

hp and 860 ft.-lb. torque, with 230 hp and 260 hp in between. The approxi-mate cost difference between the low-est and highest hp ratings, factoring in a heavier transmission required for the 300 hp engine, is as much as $8,500. This variance in engine hp/torque avail-ability and cost is common across all Class 6 and 7 truck OEMs.

Matching the right hp and torque ratings to your application. How do you choose among hp and torque op-tions? An underspec’d engine pres-ents performance and potential pre-mature maintenance issues. If you over-spec, you pay a much higher cost per unit without a correspond-ing return on investment. How do

you strike the right balance?At this stage, involve your equip-

ment upfitter and truck OEM rep for their counsel. They often have experi-ence working with fleets in your indus-try and can offer specific recommen-dations so you don’t have to reinvent the wheel.

However, a few general principles, based on common applications can serve as a guide.

Higher hp and torque applica-tions:

■ Over-the-road with heavy load, such as a towing and recovery vehicle.

■ Hilly, mountainous region.■ Over-the-road pulling a heavy

trailer.

Lower to mid-range hp and torque application:

■ Pickup and delivery where the truck does not need to reach full high-way speed often.

■ Slower speed applications such as asphalt spreader, dump body, or me-chanic’s crane/service body truck.

■ Over-the-road, on flat terrain, with lighter load.

the BOttOM Line Which scenario best matches your application? When you’ve defined exactly what you need the truck to do, you have the information you need to match the right engine to do the job.

When spec’ing the right engine for a medium-duty truck, whether new, rebuilt, or remanufactured, the main considerations are:

n What exactly is the truck expected to do?

n how long is the engine expected to last?

At A gLANcE

■ DD13*• 350 hp – 450 hp @ 1,800 rpm.• 1,350 ft.-lb. – 1,650 ft.-lb. torque @ 1,200 rpm.• I-6 12.8L.• Direct fuel injection.• Features: B-50 life of 1 million miles.• Applications: Freightliner Cascadia (2009) and additional Freightliner and Western Star models (2010).

■ DD15*• 455 hp – 515 hp @ 1,800 rpm.• 1,550 ft.-lb. – 1,750 ft.-lb. torque @ 1,100 rpm.• I-6 14.8L.• Direct fuel injection.• Features: B-50 life of 1.2 million miles.• Applications: Freightliner Cascadia, Century, and Columbia; and Western Star 4900FA, 4900SA, and 4900EX.

DEtROIt DIESEL

* not currently 2010 emission compliant.

12 WORK TRUCK JANUARY/FEBRUARY 2009 www.worktruckonline.com

truck Engines

■ px-6• 200 hp – 325 hp.• 520 ft.-lb. – 750 ft.-lb. torque.• I-6 6.7L.• Fuel injected.• Features: Right-weight, parent-bore engine.• Applications: Standard with the Peterbilt Model 330 and optional for the Model 335.

■ px-8• 240 hp – 330 hp.• 660 ft.-lb. – 1,000 ft.-lb. torque.• I-6 8.3L.• Fuel injected.• Features: Fully rebuildable, wet-sleeve engine.• Applications: Standard on Peterbilt Model 335 and 340.

pAccAR / pEtERBILt

■ 6.0L pOwERStROkE v-8• 235 hp @ 3,150 rpm.• 440 ft.-lb. torque @ 1,660 rpm.• V-8 6.0L.• Features: EVRT electronically controlled turbocharger. • Applications: Ford E-Series.

■ 6.4L pOwERStROkE v-8 tURBODIESEL• 325 hp – 350 hp @ 3,000 rpm.• 600 ft.-lb. – 650 ft.-lb. torque @ 2,000 rpm.• Features: Two-stage turbocharger.• Applications: F-350, F-450, and F-550 Chassis Cabs.

■ 6.8L v-10 tRItON• 362 hp @ 4,750 rpm• 457 ft.-lb. torque @ 3,250 rpm.• V-10 6.8L.• Features: Fail-safe cooling system.• Applications: Ford F-Series.

FORD MOtOR cO.

■ MAxxFORcE 7• 220 hp - 260 hp @ 2,600 rpm.• 560-660 ft.-lb. torque @ 2,800 rpm.• V-8 6.4L.• Direct injection.• Features: 2010-compliant without additional after-treatment.• Applications: International DuraStar, Class 5-6.

■ MAxxFORcE Dt• 215 hp - 300 hp @ 2,300 rpm.• 560-860 ft.-lb. torque @ 2,400 rpm.• I-6 7.6L.• Direct injection.• Features: 2010-compliant without additional after-treatment.• Applications: International DuraStar and International WorkStar, Class 6-7.

■ MAxxFORcE 9• 300 hp - 330 hp @ 2,000 rpm.• 860 -950 ft.-lb. torque @ 2,200 rpm.• I-6 9.3L.• Direct injection.• Features: 2010-compliant without additional after-treatment.• Applications: International DuraStar and International WorkStar, Class 6-7.

■ MAxxFORcE 10• 310 hp - 350 hp @ 2,000 rpm.• 1,050 - 1,150 ft.-lb. torque @ 2,200 rpm.• I-6 9.3L.• Direct injection.• Features: 2010-compliant without additional after-treatment.• Applications: International WorkStar and International TranStar, Class 7.

INtERNAtIONAL / MAxxFORcE ENgINES

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When it comes to replacing a truck engine, should you rebuild or overhaul, purchase a remanufactured engine, or just get a new truck? Bob Boeglin, national sales manager, from Jasper engines and transmissions offers his advice.

First, what’s the difference between these engines? “Many times, the difference between remanufactured,

rebuilt, or overhauled engines is simply how long it will last,” said Boeglin.

Overhauling an engine is a less labor-intensive process. the repair shop will fix any problems, re-ring the pistons, grind the valves, and wash and paint the engine.

according to Boeglin, a rebuilt engine is better still, “but not at the grade of new.” in a rebuilt engine, pistons are replaced, the valves are ground, old springs are reused, there may be some updates, and parts may or may not meet OeM specs.

to rebuild is to recondition by cleaning, inspecting, and replacing severely worn or broken parts. Serviceable parts are reused within the manufacturer’s acceptable wear limits. the quality of rebuilt components varies widely and many

come with only a limited warranty.Used components are pulled directly from a vehicle

— typically a junkyard vehicle — and generally not so much as surface-cleaned. Used or junkyard components may have high mileage and a poor maintenance history — a failure waiting to happen, according to Boeglin. Many used or junkyard components come from a vehicle that was involved in an accident and may have unseen damage.

Remanufacturing is the process of building an engine as good as or better than new with the most current updates and new parts.

Most wearable parts are automatically replaced and all core material is closely inspected and checked against origi-nal equipment specifications. Replacement parts are new or requalified. if new, parts are made in the same production processes as original equipment.

When deciding whether to overhaul/rebuild, remanu-facture, or purchase a new engine, according to Boeglin, it comes down to how long you need the engine to last and your goals for the vehicle.

REBUILt, REMANUFActURE, OR BUY NEw?

■ ISUzU 4H DIESEL ENgINE• 205 hp @ 2,400 rpm.• 441 ft.-lb. torque @1,850 rpm.• 4-cyl. 5.2L.• Turbocharged/Intercooled.• Features: B-10 rating of 310,000 miles.• Applications: NPR and NPR Crew Cab; NQR; and NRR.

■ ISUzU 6Hk1-tc DIESEL ENgINE• 215 hp @ 2,200 rpm.• 560 ft.-lb. torque @ 2,400 rpm.• 7.8L.• Turbocharged, direct injection.• Features: 3-year unlimited warranty.• Applications: F-Series, T-Series.

■ vORtEc 6000 gAS ENgINE• 325 hp @ 5,000 rpm• 360 ft.-lb. torque @ 4,400 rpm.• V-8 6.0L.• Fuel injected.• Features: 200,000-mile design life.• Applications: NPR and NPR Crew Cab

■ DURAMAx 6600 tURBODIESEL• Up to 360 hp @ 3,200 rpm.• Up to 650 ft.-lb. torque @ 1,600 rpm.• V-8 6.6L.• Direct injection diesel.• Features: Anticipated useful life beyond 200,000 miles.• Applications: Chevrolet Silverado HD, Express, Kodiak Medium-Duty; GMC Sierra HD, Savana, and C Series 4/5.

gENERAL MOtORS / ISUzU