There are a lot of different heavy duty engines to choose from to power your construction, farm, and logging equipment, semi trucks, delivery trucks, or other commercial vehicles, but these top picks keep selling and re-selling year after year. If you have used a few of the diesel engines on this list, then be sure to let us know your favorite on Facebook! Have another engine that should be featured on the list? Let us know.
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Cummins 3.9L (4BT)
A favorite in the logging industry since 1983, Cummins 3.9 (4BT) are extremely affordable engines found in smaller delivery trucks, wood chippers, and practically any other medium-duty machine. This 4-cylinder cylinder diesel engine has 105 horsepower and 265 pounds of torque (pre-1998). Anything after the year 1998 has 170 horsepower and 420 pounds of torque, so always pay attention to the year when choosing.
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5.9 Liter Cummins
From 1989 to 2007, the 4-cylinder Cummins 5.9 engine served as the follow-up design to the 3.9 series. The 5.9 QSB design is meant for off-road heavy equipment while the ISB 5.9 version is primarily used for commercial trucks and buses. Argued by many to be “the best Cummins engine ever made” due to its excellent torque ratings.
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Cummins ISB 6.7
First introduced in 2007, Cummins ISB stands for “Interact System B”, which gives computer upgrades to the diagnostics equipment, turbocharger and control system (for better fuel consumption rates and lower emissions output). The ISB 6.7 Cummins engine has become the standard for most heavy-duty trucks. While the 5.9 L Cummins is meant for light duty, the ISB 6.7 has 360 horsepower and up to 700 pounds of torque, making it an excellent diesel design for medium-duty jobs.
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8.3 L Cummins
Originally introduced in 1985, the Cummins 8.3 L series is still widely used for construction, agriculture, forestry, and stationary mining applications. The 6C (6 cyclinder) 8.3 L Cummins engine is especially popular with Peterbilt, Kenworth and Volvo trucks. With up to 270 horsepower, this reliable engine can gets the job done at a steady (but not exactly “blazing”) pace.
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L10 Cummins Engine
The L10 Cummins engine are especially popular for tandem commercial trucks and single axle dump trucks. Although they do not perform very well on hills, these 260-330 horsepower diesel engines (with 2,300 rpms) can smoothly haul heavy loads with ease and have been reported to compare to 400 horsepower commercial trucks.
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Cummins M11
If you need something stronger than the 8.3 L C series, Cummins M11 engines have a 10.8 liter displacement and a horsepower between 280 to 330 horsepower. Many consumers have reported getting around 800,000 miles without any major issues (with proper maintenance), so don’t be surprised if the engine outlasts the truck (or any other piece of heavy equipment you use it for).
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Cummins ISC Engine
This follow-up design to the Cummins M11 is available in 6 different models ranging from 240 horsepower to 330 horsepower, making the Cummins ISC engine a strong selection for medium duty trucks and off highway vehicles. Its special rail fuel system balances emissions, performance and fuel consumption – no matter how fast the engine is going.
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Cummins ISX Engines
Cummins ISX engines came out in 1998 and have enough power for heavy duty jobs such as mining, industrial construction, and for running the largest power generators on the market. With up to 600 horsepower and 1,450 pounds of torque at 1,200 RPMS, the original Cummins ISX CM570 quickly replaced the N14 engine with a new fuel system and dual overhead cams for a higher performance with more raw power.
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Cummins QSM11
The Cummins QSM11 is available in a number of models all the way up to 660 horsepower. The 6-cylinder design has a low profile for easy installation and servicing, making it a trusted construction engine of choice. Any design ranging from 290-400 horsepower is equally popular for cranes, loaders, excavators, tractors, drilling machines and generator sets depending on the size and scope of the job.
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N14 Cummins Engine
Although some fuel injector issues were reported in early models, the n 14 Cummins engine offers between 310 and 525 horsepower along with 1,250 to 1,850 pounds of torque at 1,200 RPM, giving it an excellent turning maneuverability. Its long-lasting design has made it an affordable favorite among commercial trucking, agricultural and construction companies.
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Cummins QSK19
The Cummins QSK19 engine is available from 755 to 800 horsepower. Aside from raw power, an easy maintenance design makes this engine popular for the largest of heavy equipment. For example, the oil filter requires just two steps to change. Overhauls are generally required every 18,000 hours.
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Cummins KTA 19 Engine
Available in four different models, the Cummins KTA 19 engine series is available from 525 to 600 horsepower. With over 30 years of production and counting, the KTA 19 engine is especially popular due to its low total cost of ownership (fuel, maintenance and longevity). Construction, mining and even marine designs are readily available.
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Detroit Diesel 60 Engine
Many compare the 6-cylinder Detroit 60 series engine with the Cummins N14 in terms of reliability and performance. The N14 reportedly has a little more torque and towing power, but the parts are more expensive to replace than the Detroit 60 series. The Detroit 60 series engine has 11.1, 12.7 and 14 liter varieties, and there have been many changes over the years. The 2001 14 L Detroit 60 series models – with 575 horsepower and 1,850 pounds of torque – are especially popular for heavy duty construction.
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Detroit DD15 Engine
Detroit Diesel's DD15 heavy-duty diesel engine debuted in 2007 and has been a popular engine ever since. The Detroit DD15 engine features 1550-1750 lb-ft of torque, has horsepower ranging from 400-505, and 14.8l displacement. The DD15 is most commonly seen in Freightliner Cascadias and Western Star trucks.
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Cat 3116 Engine
The Caterpillar 3116 turbocharged diesel engine is primarily used for truck hauling. With up to 350 horsepower, it is powerful enough to tow loaded trailers up steep hills and for boat towing as well. Many consumers report that it has way more power than they were expecting, which is why it has remained a top choice for years.
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3126 Cat Engine
The Caterpillar 3126 turbocharged 7.2L inline 6-cylinder diesel engine was often used for commercial trucks, like the Freightliner FL70, and heavy machinery. It is another Cat engine that has a HEUI fuel system. With horsepower ranging from 175-330, the 3126 Cat is a mid-range diesel engine good for delivery trucks and more. The 3126 Cat engine was replaced by the Cat C7 engine in 2003.
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Cat 3204 Engine
As one of the smaller 4-cylinder models available, a Cat 3204 diesel engine can power slow-moving heavy equipment for smaller jobs where horsepower is not as important. The 3204 NA model has 105 horsepower and the 3204T model has 160 horsepower (both at 2,800 rpms).
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Cat 3304
Introduced in 2009, the Cat 3304 churns out 95 bhp at 1,800 rpms when at 100% operating capacity, and 71 bhp and 1,800 rpms (again) at 75% operational capacity. Some optional specifications include a battery charger, blower fans, mufflers, and air pressure regulators.
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Cat 3306
The Cat 3306 engine has a horsepower rating between 218 to 360, making it effective for commercial truck hauling, general work around the farm and much more. Though they are not the cleanest-burning engines on the market, the Cat 3306 has a powerful design that will last an extremely long time with proper maintenance.
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3406e Engine
Although some have reported rare problems with cooling, the 3406e engine series is popular thanks to its extremely easy maintenance. Unlike the 3406 “B” series, for example, which requires new rods and mains every 350,000 miles, the “E” series only requires such maintenance if the oil analysis says so.
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C7 Caterpillar Engine
From 2003 until 2009, the 6-cylinder C7 Caterpillar engine was primarily used for medium-duty trucks with a gross vehicle weight rating of 18,000 to 33,000 pounds. Models range from 210 to 360 horsepower, with torques between 520 to 925 pounds and a displacement of 7.2 liters. High torque and low torque options are available for some models.
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C9 Cat Engine
With 335 to 350 horsepower at 2,100 rpms, the turbocharged C9 Cat Engine can power its way through larger jobs that the C7 cannot easily or speedily handle. If you need to complete a job quickly using medium-duty trucks and off-road machinery, then the C9 Cat engine is a versatile and reliable purchase for those who are willing to pay a little extra.
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Cat C10 Engine
First introduced in 1995, the Cat C10 engine is primarily used to power trucks and buses. This 10.3 liter diesel engine is one of the earliest to feature an Electronic Control Module and other electronics designed to improve overall performance. The horsepower is 335 (350 max) and the engine rpm is 1,800, making it suitable for off-road and highway handling.
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Cat C12 Engine
With 430 horsepower at 1,600 rpm, the Cat C12 engine is a popular choice for off-road and highway vehicles and heavy equipment. However, any Cat C12 diesel engine from 2003 must have their fuel settings checked because of a manufacturing oversight that has caused problems from overheating.
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Cat C13 Engine
A Cat C13 engine is a strong choice for heavy equipment requiring 380 to 430 horsepower at 2,100 rpm. Everything from agricultural machines (including ag tractors) and construction equipment to boring and drilling equipment are regularly outfitted with a Cat C13 engine.
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Cat C15 Engine
A Cat C15 engine is an in-line, six-cylinder heavy-duty diesel engine. Everything from agricultural, forestry, and construction equipment to commercial trucks utilize the Cat C15 engine, which has a power rating of 435 to 625 horsepower at 1800-2100 rpm. The displacement is 15.2 liters, or 928 cubic inches and torque is 1550 to 2050 lb-ft at 1200 rpm. The Cat C15 has a weight of 3090 pounds.
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