Engines Now Mostly Aligned with Trucks

By Tom Berg, Contributing Editor | September 28, 2010
Your Engine Choices

Many truck models were updated to take EPA-2007 diesels and sold as 2007s, then became 2008s with the normal model-year turnover. Others became '08 models early in '07 with the installation of new engines and larger cooling systems, and the more complex exhaust systems to accommodate body builders. Following are domestic and foreign truck manufacturers and the engines they offer on Class 6 through 8 commercial trucks, with comments on lighter-duty commercial trucks, where appropriate.


The new Chrysler Dodge Truck arm has burst into the medium-duty market with several "heavy-duty" Ram Cab Chassis models. They have stout frames and beefed-up suspensions, brakes and other components. In late 2006 came the 3500 HD, and a year later 4500 and 5500 HD models went into production in Mexico. They use a 6.7-liter Cummins Turbo Diesel that, at 310 hp and 610 foot-pounds, is slightly derated from the high-output version used in pickups (already emissions-legal for 2010). Chrysler also builds the 4500 and 5500 HDs for Sterling, which sells them as its Bullet.


F-650 and F-750 conventionals are standard with the Cummins 6.7-liter ISB with 200 to 325 hp and available with Caterpillar's 7.2-liter C7 with 10 power/torque ratings. Ford says its most popular commercial engine rating is 240 hp, compared to 210 hp a few years ago. F-250, 350 and 450 SuperDuty pickups with chassis cabs use a 6.4-liter International-built PowerStroke V-8 diesel, while E-series vans use the older 6-liter version. All the trucks are also available with Triton V-8 and V-10 gasoline engines. Ford's Class 3 and 4 LC low-cab-forward truck, built under the Blue Diamond joint venture and sold by International as its CityStar, comes with an International-made 200-hp V-6 diesel.


Business Class M2 comes in on-highway and vocational models with heavier chassis components. The M2-106 short conventional is standard with the 6-cylinder Mercedes-Benz 926, while the Cummins ISB and ISC are optional. The Cat C7 is no longer offered. M2-112 is standard with MBE 4000 and available with Detroit Series 60, each with several heavy-duty ratings. FLD-SD is standard with a 455-hp Series 60. Freightliner's Century S/T, Columbia and Coronado road tractors come with MBE 4000, Detroit Series 60 and optional Caterpillar C15 power; as does the new Cascadia highway tractor — the first to use Detroit's new DD15 with 455 to 560 hp and torque of 1,550 to 1,850 foot-pounds.

General Motors

For diesels, Chevrolet Kodiak and GMC TopKick C4500 and 5500 use GM's own 6.6-liter Duramax V-8, which is also used, along with gasoline V-8s and a V-6, in lighter-duty pickups and vans. C6500 and 7500 have 7.5 percent more standard power and torque than the base Isuzu 6H, now at 215 hp, and the optional Caterpillar C7, at 210 to 250 hp. The 8.1-liter Vortec gasoline V-8, at 295 hp, is also available in those trucks and the heavier C8500, making GM the only builder to continue offering gasoline power in medium- and heavy-duty vehicles. Chevy and GMC tilt-cab T-6500 through 7500 mediums, plus a tandem-axle T-8500, use only the Isuzu 6H diesel.


Hino conventionals are assembled in California (and soon in West Virginia) using cabs and engines from Japan, while all other components are sourced in the United States. Four Class 6 and 7 models are offered with a 7.6-liter, 220-hp in-line 6-cylinder diesel that's used in all models. Lighter models designated 145, 165 and 185 use a 4.7-liter in-line 4-cylinder diesel with up to 175 hp.


Most trucks got new Star-suffix names in 2007, and all of International's diesels are called MaxxForce. The DuraStar 4300, as a regular or low-profile 4x2, uses the 7.6-liter MaxxForce DT (formerly the DT 466), at 210 to 330 hp, and the 6.4-liter MaxxForce 7 V-8, at 200, 215 and 230 hp. The DuraStar 4400, in regular and low-profile 4x2 configurations and as a "Baby 8" 6x4, uses the MaxxForce DT and the 9.2-liter MaxxForce 9, at 285 to 330 hp. The 7000 series WorkStar vocational trucks and tractors use a MaxxForce 9, or optional Cat C13 or Cummins ISM. PayStar 5000 trucks and tractors use Cat C15 or Cummins ISX diesels, and a lightweight PayStar heavy-mixer chassis uses a Cummins ISL. ProStar and 9900i highway tractors (the latter will be replaced by a new LoneStar long conventional) come with heavy-duty Cat or Cummins power. New 11- and 13-liter MaxxForce diesels based on European MAN engines are due out later this year, and will probably become standard in many International heavy trucks.


Although a joint venture with General Motors ended, Isuzu still has alliances with GM and one results in the Chevrolet/GMC T series and Isuzu F series Class 5 through 8 low-cab-forwards. GM assembles them in Michigan, using cabs and engines from Japan, and many drivetrain and chassis components from North America. They use the Isuzu 6HK1-TC diesel with 215 to 300 hp. Cat's C7 was dropped from the tilt-cabs several years ago, but is still available in GM's C-series conventionals. Redesigned lighter-duty Isuzu N series and Chevy/GMC W series low-cab-forwards are built in Japan using a 5.2-liter 4HK1-TC diesel with 205 hp or in Wisconsin with a GM 6-liter 325-hp Vortec gasoline V-8.

Mack Trucks

Although Mack and Volvo trucks differ in design and construction, both makes use diesels from Volvo Powertrain, the engine- and transmission-making arm of Sweden's Volvo AB. It builds 11- and 13-liter diesels in Maryland. Except for paint color (deep red for Mack and green for Volvo), the engines are mechanically identical, but are said to differ in operating characteristics. MP (for Mack Power) engines come in three types of tune, including high-torque-rise Maxidyne for Granite vocational trucks, plus MaxiCruise and Econodyne versions for highway trucks. The 11-liter MP7 has ratings of 325 to 405 hp and the MP8 goes from 425 to 485 hp. Mack says a 16-liter MP10, based on the Volvo D16, will come later, and a new long-nose tractor might be designed around it.

Mitsubishi Fuso

Fuso redesigned its '08 low-cab-forward lineup for more driver and passenger comfort and increased carrying ability. Midrange FM and FK models have a 7.5-liter 6M60 in-line six-cylinder, single-overhead cam turbodiesel rated at 243 hp. Its lighter-duty FE and 4x4 FG trucks use a 4.9-liter dual-overhead cam 4M50 diesel at 185 hp. Fuso is now part of Daimler's commercial truck operations, which could affect future products.

Nissan UD

Nissan Diesel America's UD-brand includes midrange low-cab-forward trucks with a 7.7-liter MD230 in-line 6-cylinder turbodiesel at 230 hp. Lighter-duty UDs have a 4-cylinder MD175 diesel. Nissan is now partly owned by Volvo AB.


Kenworth Truck and Peterbilt Motors each build heavy-duty trucks and design their own medium-duty conventionals, and they compete strongly through separate dealer networks. But they are owned by Paccar, which makes the decisions on engine offerings, so medium-duty Kenworth T series and Peterbilt sub-300 series conventionals now come exclusively with Cummins-built Paccar PX 6 and PX 8 diesels. Midrange LCF trucks (made by Paccar's DAF subsidiary in Europe) come only with the PX 6. Kenworth's C, T and W series heavy conventionals and Peterbilt's 380-series conventionals are standard with Cummins ISM and ISX power and available with Cat C9, C13 and C15 engines. DAF in Europe is helping prepare a new heavy-engine series, the 12.9-liter PX 13, which will become standard on Kenworth and Peterbilt. Production of the PX 13 will start next year in Mississippi.

Sterling and Western Star

Sterling's medium-duty Acterra comes with the 190- to 300-hp M-B 926, while the Cummins ISB, at 200 to 300 hp, and ISC, at 240 to 330 hp, are optional (Cat's C7 has been dropped). Heavy Acterras and the L- and A-Line heavies come with MBE, Detroit Series 60, and Caterpillar's C13 and C15. Cat engines have remained popular with Western Star buyers, though lower pricing on Detroit engines has swayed some customers. The new DD15 will become available later this year.


Volvo's D series 11- and 13-liter diesels are mechanically akin to Mack Power engines. There's also a 16-liter D that was actually the first in the new engine family from Volvo Powertrain. The D11, Volvo's lightweight engine with 325 to 405 hp, and D13, with 335 to 485 hp, are oriented toward Volvo's VN highway tractors, though its VHD vocational truck comes only with a D13. The D16, first offered as a 2006 with up to 625 hp and 2,250 foot-pounds, has been slightly derated for 2007 with 450 to 600 hp and 2,050 foot-pounds. It's available in long-nose VNL and the long-and-tall hooded VT trucks and tractors. Cummins' ISX in several ratings is also available in VNL and VT series.

Does anyone buy trucks to get a certain engine anymore? Yes, but loyalty to engines — and transmissions and other components, for that matter — isn't what it used to be. It's a slow reaction to vertical integration, where truck original equipment manufacturers (OEMs), rather than customers, decide what will go into vehicles. This has long been the practice in Europe and Asia, and buyers accept it. In North America, however, customers are forgetting their specifications preferences as OEMs field proprietary products that do the work just as well.

For many years OEMs have culled slow-selling "oddball" components from their options lists. This was most visible in transmissions, but also affected everything from air dryers to axles. Long gone are "double-stick" transmissions, which used two separate gearboxes to achieve the multiple ratios needed by most diesels, as well as "air-shift" types and other adaptations. Only the most popular manual transmissions, primarily 10-, 11-, 13- and 18-speed models, have survived, working alongside full automatics and a new class of self-shifting automated mechanical transmissions. Eaton and Allison are the main names here.

Customers can still specify engines in heavy trucks, but the choices are fewer in recent years as consolidation among truck manufacturers and strategic agreements between them and suppliers have shortened all manufacturers' options lists. Most makers of medium- and light-duty trucks have long built their own engines.

International designs and builds its own midrange diesels and is now preparing to produce its own big-bore models. Paccar, parent company of Kenworth and Peterbilt, has now gotten into the engine business with its PX-branded products. Freightliner has linked up with Detroit Diesel and Mercedes-Benz, owned by Freightliner's parent Daimler AG of Germany. And Mack, the only North American OEM with a long history of vertical integration, still is, although it's now a sister to Volvo Trucks.

Engine suppliers

While there are many engines in the marketplace, only two builders — Caterpillar and Cummins — can still be called vendors. Various Cat and Cummins diesels are available in truck models from 11 domestic manufacturers (the number depends on whether one counts companies or nameplates). The list has shrunk in recent years as the manufacturers move toward proprietary components. Cat engines are available in Ford, General Motors (Chevrolet and GMC), International, Paccar (Kenworth and Peterbilt), and Freightliner-Sterling-Western Star. Cummins diesels are offered by Dodge, Ford, International, Paccar, Volvo and the Freightliner family.

These days, it's more meaningful to list engines by truck manufacturers because they all have proprietary engines that are standard and charge premiums for optional engines, if they offer them. Sometimes a truck maker touts the vendor's reputation, as Dodge has since the 1989 model year with its now popular Cummins Turbo Diesel (a modified ISB). Paccar, on the other hand, uses its own labels, PX 6 for the Cummins ISB and PX 8 for the ISC, because it's trying to build its own identity in engines. The engines are painted dark grey instead of Cummins red and use private-branded accessories.

In recent years, Cummins secured agreements with Mack and Volvo for heavy-duty diesels, but Mack (now a sister company to Volvo) dropped them completely in the '07 model year. Volvo continues to offer the ISX in its highway trucks, but seems intent on converting Cummins users to its own D-series engines.

Cummins is also a preferred supplier to Paccar's Kenworth and Peterbilt brands via the PX name and is the exclusive engine supplier in Paccar medium-duty trucks. Paccar offers both Cat and Cummins heavy-duty engines, but emphasizes Cummins, both in pricing and marketing efforts. It says it will continue to offer the two vendors' engines after it begins building its own PX-brand heavy diesels in time for the 2010 model year.

International uses Cat and Cummins engines in its heavy truck models, but later this year will build its own MaxxForce heavy engines. The company says it will continue to offer the vendor engines as long as customers want them. A major engine maker for many years, International continues to use only its own medium- and medium-heavy MaxxForce diesels in its trucks. The company's Work Horse Custom Chassis subsidiary uses a MaxxForce V-6 diesel but buys gasoline V-8s from General Motors.

Caterpillar's position as a vendor seems precarious because it doesn't have preferred status with truck builders and its share of the Class 6, 7 and 8 markets has shrunk considerably. Its C7 midrange diesel has been dropped by all truck manufacturers except two: Ford, which still considers the C7 its premier medium-duty engine, and General Motors, which is emphasizing the 6H diesel supplied by Isuzu and reports that the C7 has lost popularity. Cat's C9, C13 and C15 are still offered by several heavy truck makers, but they all either have their own engines as standard or will have.

Some observers think Cat will leave the truck engine business by 2010, when tighter emissions limits take effect. Another speculation — which includes the side comment that Caterpillar is a huge and very strong corporation — is that Cat will begin building its own heavy trucks.

Detroit Diesel, once a popular vendor with its old two-stroke and later four-stroke models, was acquired in 2000 by Daimler-Benz of Germany (now Daimler AG) through its American truck manufacturer, Freightliner LLC (now called Daimler Trucks North America). So Detroit devotees can order those engines only in Freightliner family trucks, which include Sterling and Western Star.

Daimler sold Detroit Diesel's off-road products and business and melded its own Mercedes-brand commercial engine operations into the organization. The plant in Redford, Mich., has been assembling Mercedes-Benz 900 medium-duty engines for more than a year. By 2010, the current Detroit Series 60 and MBE 4000 heavy diesels will be replaced by a new DD15 series and new midrange diesels are also due out.

Volvo Powertrain, which supplies diesels to Volvo Trucks and Mack Trucks, began building an entirely new engine family at a retooled Mack engine plant in Hagerstown, Md., last year. While the 11- and 13-liter heavy-duty engines are mechanically all but identical, the two truck makers claim they have different operating characteristics. Mack Power engines include three sub-types for varying applications, reflecting Mack's traditional catering to specialty markets, while Volvo's D models are more geared toward highway use.

Most midrange truck manufacturers, including domestics and importers, design and build their own diesels and use them exclusively in their vehicles.

Ford's V-8 diesels, used mostly in its Class 2, 3 and 4 SuperDuty models are distinctive, as they offer more power and torque than International's own MaxxForce 7 versions and use double turbocharging vs. single turbos on the MF 7s. But serious legal squabbles between the two builders over an earlier version of the V-8 could put the relationship in jeopardy.

International insists that the Blue Diamond joint venture between it and Ford will continue. This "contract manufacturing" agreement has International building Ford's medium-duty F-series conventional-cab trucks using components from both companies, plus engines from Cummins and Caterpillar, at a plant in Mexico. That plant also builds Class 3 and 4 low-cab-forward models sold by both Ford and International dealers that use a MaxxForce V-6 diesel and a Ford TorqShift automatic transmission.

Likewise unaffected by the Blue Diamond deal is the tentative agreement under which International will buy General Motors' Class 4 through 8 medium-duty trucks. If the details are worked out, by year's end International will take over the GMC TopKick and Chevrolet Kodiak conventional-cab products, as well as T-series low-cab-forwards now made by GM in Flint, Mich. International will build those products in its own facilities and sell them through GM dealers. The trucks will remain the same, using engines from GM, Isuzu and Caterpillar, though business analysts think International will eventually offer the trucks with its diesels.

Ford no longer builds Class 8 trucks, but could resume doing so now that a 10-year non-competitive agreement with Freightliner, under which Ford sold its "HN80" Class 8 products that became the Sterling A- and L-Lines, has expired. Class 8 Fords would likely be based on the F-650/750 and thus would be "Baby 8s" with midrange powertrains.

All diesel-powered 2008-model trucks have EPA '07-compliant engines with advanced combustion, air-handling, and exhaust systems, plus bigger cooling systems, to meet emissions limits. These advances allowed builders to offer more standard horsepower and torque in their medium-duty diesels — typically 200 hp or more, where base ratings previously were typically 175 hp. That's a bonus of sorts for the higher prices most began charging for the 2007 diesels to try to recoup heavy investments required for research and development.

Price hikes were known in advance by customers and dealers, many of whom purchased trucks with the less costly pre-2007 engines. That contributed to the current depression in sales of heavy trucks and also hurt sales of midrange and light trucks. One exception is Dodge, which is expanding its efforts in commercial truck sales partly by holding the line on the price of its Cummins Turbo Diesel option, at about $6,000 above a gasoline-powered truck.

While vendor engines are still a factor, especially in heavy-duty trucks, the alliances and strategic agreements — both part of the trend toward vertical integration — makes the vendors less important now, and truck dealers say loyalty to engine makes is waning. Some buyers of construction trucks are still willing to pay thousands more for a particular engine, but most are sobered by price differences and will go with an OEM's lower-cost standard engine, especially if it has established a good reputation.