Best Diesel Engine: Top 18 Engines For all Use case Scenarios

International DT466

You have probably been in the vicinity of International’s DT466 even if you are unaware of it. This renowned I-6 has provided power to dozens of different applications throughout the years, including city buses, box trucks, agricultural tractors, and even small bulldozers. The DT466 was the largest engine in the 400 series produced by IH. It was the big brother of the 414 & 436 ci tractor engines, which all utilized the same block design. 

The original configuration of the DT466 can endure a significant amount of punishment because it has a sturdy rotating mechanism with six head bolts on each cylinder as part of its physical makeup. Before reaching this point, you are free to add as much fuel and air as you like without having to worry about any kind of hard-part upgrades.  Additionally, it has established a true habitat in the sport of tractor pulling. 

6BT Cummins

The B-series 5.9L Cummins, the 6BT, revolutionized pickup trucks and made this magazine possible. Without it, the diesel business wouldn’t have exploded and Diesel World might not exist. 5.9L Cummins helped expand the diesel industry. The 12-valve Cummins brought I-6 design, direct-injection technology, and turbocharging to 3/4-ton and larger trucks in 1988, and Ford and GM have been playing catch-up ever since. One look at the 6BT’s connecting rods shows why this overbuilt inline-six might survive a million miles or handle 400 hp.  

The crankshaft is attached to the cast-iron block with 14mm main cap bolts and the cylinder head with six bolts per cylinder. The 5.9L block is still a viable alternative for up to 1,400-1,500 hp. We’ve seen plenty of 5.9Ls with 1,100-1,200hp. The crossflow, 12-valve 6BT Cummins cylinder head was cast from grey iron.  Diesel motorsports favor 12-valve heads (and aftermarket variations). It can flow over 300 cfm per cylinder with CNC and/or hand porting and oversize valves.

3406 CAT

Thousands of Class 8 trucks still rely on this engine to run trouble-free across America. It’s Caterpillar’s famed 3406, and truck owners swear by it. The 3406 bore 5.40 inches, stroked 6.50 inches, and displaced 893 cubic inches in A, B, C, and E models (14.6L). Model-specific horsepower ratings ranged from 375 to 465 HP, with 1,850 lb-ft of torque. The most revered 3406 has an “E.” The 3406A, 3406B, and 3406C were entirely mechanical engines; the 3406E was CAT’s first electronic engine (circa 1993). 

The 3406E’s hot-rod character helped it gain a cult-like following, with 550 and 600hp files common. In mega-horsepower competitions like 20,000-pound semi-sled hauling, many drivers pick a 3406. Jerry and Jeremy Walker, a legendary father-son duo, ran ragged edge versions in their semis, a Peterbilt named “Two of a Kind” and an International called “Down ‘N out.” Both engines have more than 1,000 ci and a 5-inch turbo.

7.3L Power Stroke

The 7.3L Power Stroke won’t win any horsepower awards or start easily in the cold. The Navistar-produced 444 cc V-8 had a 4.11-inch bore, 4.18-inch stroke, 210 HP, and 425 lb-ft when it debuted in mid-1994. Caterpillar leased the 7.3L Power Stroke’s hydraulically operated electronic control unit injector technology (HEUI) to International to meet pollution standards. It was Ford’s first real response against the Dodge Ram which uses a 5.9L Cummins engine. The 7.3L has a crafted crankshaft, forged-steel linking rods, straightforward injection, and cast-aluminum cylinders with plasma-coated upper piston rings. Cast-iron heads had two valves in each cylinder and six head bolts (with sharing). 

One camshaft in the usual V-8 location in the block with hydraulic lifters allowed no periodic valve adjustment. Low engine speed, large iron components, and (let’s face it) lack of power make any diesel last, and the 7.3L possessed all three. The most powerful 7.3L engine produced 275 HP and 525 lb-ft of power, a far distance from the 1,000 lb-ft types of diesel on dealer lots today. HEUI injection is frowned upon by mechanical injection aficionados, common-rail owners, diesel outsiders, and even those whose first introduction to hydraulically actuated fueling was the 6.0L Power Stroke. 7.3L injectors increased the oil compressor, and the injection pressure gauge was reliable. Properly maintained injectors can last 200,000 miles or more before needing replacement. Repair shops still take original injectors (with black O-rings) from 7.3L engines 19 years after manufacturing ended.

Cummins 855 Big Cam

Cummins introduced the 855 Big Cam to meet Clean Air Act pollution standards in 1976. It was the most fuel-efficient, durable, and powerful Class 8 truck engine in the 1970s and 1980s. The 855 ccs (14.0L) Big Cam I (four versions available) had a 5.50-inch bore, 5.98-inch stroked, and most versions had 250 to 400 horsepower. In gen-set form, many 855 Big Cam engines produced 605 horsepower. The Big Cam I, II, and III used Cummins’ PT fuel system, which permitted dynamically changeable timing. Big Cam IV added electronics in 1985, although it was quickly supplanted by the N14. 

John Deere 50 Series 6-619

After having mentioned the International DT466 as one of the very greatest diesel power plants that have ever been created, it would be unethical to forget about the John Deere engine. After all, DT466-based mills have been going head to head with exotic tractor-pulling versions of the green I-6 for years now. On the racetrack, the 619-based ‘Deere tend to be dominant in classes in which their large cubic inches are allowed to run free. Because of the frequent occurrence of excessive cam wear on the 30 and 40 series engines that came before the 50 series, many owners switched to the 50 series when serious mechanical failures or difficulties were experienced. You don’t see factory-based 619 John Deere’s behind the side shields of Pro Stock tractors very often because of how wacky the world of Pro Stock tractors is. In addition, the majority of 619s have their displacement increased to the class maximum of 680 cubes so that they can compete at the highest level permitted for their class. Let’s talk about the big leagues!

Mack E7

It is worth noting any diesel engine that was produced in the 1980s but was able to make it through a significant pollution crunch before being phased out. One example of such an engine is Mack’s E7. Many people believe that the 728 ci (12.0L) E7 perfectly exemplifies the bulldog logo that the company uses. However, in classic Mack fashion, earth-rotating torque was generated directly off idle even though its horsepower ratings ranged from 250 to 460 hp. This was a significant advantage. The very first E7s were completely mechanical, but beginning in the early 1990s, electronic components started making their way into the design. 

V-MAC, which stands for “vehicle management and control,” was Mack’s first attempt at implementing electronic control over its gasoline system. This control, which was only partial, involved the addition of a rack actuator, a rack position sensor, and a timing reference sensor to the Bosch inline pump. In addition, the Mack Econovance system incorporated variable mechanical timing, which assisted in better catering the delivery of gasoline to the specific requirements of the end user. By the year 2003, EGR had begun to be installed on the redesigned 12-liter engine, and the engine that had previously covered a million miles began to gradually lose its shine.

Detroit Diesel 60 Series

It’s possible that Detroit Diesel would have continued to lose market share during the 1980s and finally gone out of business if not for the Series 60 engine series. To our great relief, that did not take place. The unit injection system of each engine was entirely electronic, and it functioned perfectly, just like the rest of the engine did. 

It has been established that in the middle of the 1980s, Detroit Diesel, which was controlled by GM at the time, contacted John Deere to solicit assistance in resurrecting its waning engine. After a short period, the 60 series entered the market. This new generation of power plants nearly eliminated all of the problems that its predecessor, the 50 series, had. Later on in the year 2001, Detroit introduced an engine that had 858 cubic inches and 14.0 liters of displacement, to compete in the market for larger engines. This type, which had a long stroke measuring 6.62-inches, was able to generate 1,650 pound-feet of torque at 1,200 revolutions per minute (rpm), in addition to 515 horsepower at 1,800 rpm.

KTA Cummins

Even though it is seen here in its configuration as a gen-set, the Cummins was the best engine that was ever discovered on the roads of the United States. The KTA was a square engine with a bore and stroke of 6.25 inches, which resulted in a displacement of 1,150 cubic inches (19.0 liters). Even though its primary purpose was never to provide propulsion for over-the-road trucks, it eventually found its way into these vehicles. In the late 1970s and throughout the 1980s, single turbo Class 8 models were able to generate a maximum of 600 horsepower, which was a highly impressive figure at the time. Cummins’ PT (compression) fuel system was utilized in the KTA, much like it was in the 855 Big Cam engine of the period. 

The KTA is capable of producing four-digit horsepower with very minor modifications to its feeding and turbo systems, which would allow it to continue functioning normally during the working week. This advantage has allowed it to dominate the ranks of hot-rod type semi-classes for years. Now for the most exciting part… In addition to it, there was a KTTA, which stands for “twin-turbo.” The KTTA is primarily intended for use by generator sets and other types of industrial equipment.

6.6L Duramax    

It is the only engine on our list to have aluminum heads and is one of only two V-8s total, but that does not mean it is any less worthy of being here than the others. When the 6.6L Duramax burst onto the market in the 2000 summer for the model year ’01 GM HD pickups, it claimed the highest power and torque than any diesel pickup had ever had before. However, it wasn’t the only thing it did differently than any other diesel pickup. In addition to its class-leading 300 horsepower and 520 pound-feet of torque, this same Duramax also led the way in the trucks segment in terms of its performance in other areas. The 4340 forged-steel crankshafts of the LB7 Duramax were subjected to heat treatment, forged-steel fractured cap rods were used, and the combustion portions of the cylinder walls were induction-hardened. 

This was something that GM’s competitors were not doing. In retrospect, the same fundamental architecture of the 6.6L Duramax engine has been in production for more than 20 years, during which time there have been very few design modifications made. It still has the same bore size, stroke length, and valve train configuration as before, with a deep-skirt cast-iron block as its foundation. Even though it is one of the much more complicated diesel on the list, there is no denying that it can travel a long distance. There have been other contenders with 500,000 miles on the ticker, and we’ve also seen a Half or full version with much more than 750,000 miles.

Chrysler

It is an EcoDiesel engine may be little, but it packs a significant punch. While the engine itself may have its roots in Cummins, VM Motori is the company that manufactures the PowerPlant. Therefore, because the Italian company cooperates with Fiat and Chrysler, we’re leveraging its domestic lineage) to make it onto our list owing to the immediate impact it made on the segment of the half-ton pickup market. Rams of the 1500 Series is the only vehicle that may be equipped with the EcoDiesel engine, which debuted in 2014. 

Cummins

The modern-day, turbodiesel pickup truck movement can be directly attributed to the introduction of the Cummins engine. Although there had been other attempts at copulating types of diesel with gentle pickups before the engine’s August 1988 public debut in a Dodge Ram vehicle the PowerPlant demonstrated itself to be the best option to Dodge’s big-block V-8 gas engine, due to its ability to produce amazing torque and achieve markedly improved fuel mileage, which was very important a generation ago. 

In addition, These engines feature the favored Bosch P-7100 infusion pump (also known as the “P-pump”), which supports power and torque well beyond the production plant 245 horsepower and 505 pound-feet of ’98 6BTs, with only minor modifications. The “Second Gen” engines, which were produced from 1994 to 1998, are preferred by hot-rod enthusiasts who are interested in diesel vehicles.

6.7L 24-Valve

The most recent iteration of the 6.7L Cummins engine will most certainly be included on our list. This engine, when installed in 1-ton Ram 3500s with Aisin’s AS69RC automatic transmissions, generates 385 horsepower and 865 lb-ft of torque. It also features a Diesel Particulate Filter and a Diesel Exhaust Fluid injection system. It provides the most amount of torque that has ever been made accessible in a pickup vehicle classified as “civilian.”

It has been demonstrated that the 6.7L Cummins is one of the greatest engines available for pickups that are capable of pulling or hauling huge loads (with factory ratings up to 30,000 pounds). And for those that compete in pickup truck racing, the 6.7L is the engine of choice for many of the heavy hitters who compete in our Diesel Power Challenge competitions.

5.0L

Indeed, 5.0L is brand new. Nevertheless, despite this, we believe that the long-awaited ’16 5.0L Cummins engine, which comes equipped with 310 horsepower and 555 lb-ft of torque, is truly destined for greatness and is an example of an engine that ought to be counted among the best in the pickup market. Nissan believes that the Titan XD can be “fuel-efficient while capable of doing real work.”

Duramax 6.6L LBZ

The 6.6L Duramax LBZ that was produced by General Motors between the years 2006 and 2007 is widely regarded as the best diesel engine the company has ever produced for pickup trucks. Why? Because it’s a dream come true for modifiers. To begin, the Duramax LBZ was constructed with a block that is more resistant to cracking under extreme pressure, larger connecting rods, new pistons with a larger pin diameter, and lower compression (down from 17.5:1) Cylinder heads were also made to be less susceptible to cracking under these conditions. When you consider that the LBZ outperformed its rivals in terms of horsepower and torque output, with 360hp (compared to 325hp for both the Cummins 5.9L 24-Valve and the Ford 6.0L Power Stroke), you can see why we have such a favorable opinion of it.

6.6L LML

GM increased the amount of power that its 6.6L Duramax engine is capable of producing by a substantial margin. Once more, a large block and internals, a newly designed oiling strategy, and next-level PCM calibration gave it the ability to make a best-ever 397 horsepower as well as 765 lb-ft of engine power, as well as being the neatest Duramax to date and obtaining 11 percent better fuel mileage than its LMM predecessor. Because of these advancements, the then-new, and still-current “LML

Navistar/Ford 

If the 7.3L Power Stroke engine is not included on this list, one might nearly claim that the list is completely worthless. Ford’s iconic engine, which was based on the International/Navistar T44E, is figuratively the icon for the no-nonsense, “git’ur dunnnn” mentality that is associated with diesel engines. This squad is best served by the 7.3L, which stands out among its peers.

6.4L Power Stroke

This engine earns a spot on our list of the best diesel for pickup trucks because it represents the company’s focus on improving the nuances of its 6.0L predecessor. Additionally, this engine represents the company’s initial foray into common-rail fueling and sequential/twin turbocharging. Both of these advancements were made by the company. Our ranking of the greatest diesel vehicles overall includes the 6.4L Power Stroke from 2008 as one of the vehicles that cut. The latter two developments served to (finally) propel Blue Oval diesel fully into the performance arena, which is the area in which they continue to thrive to this day with the addition of aftermarket modifications.