by Bo Griffith, Certified Diesel Mechanic
Ever since diesel pickup trucks started getting popular back in the late 80’s, there has been a debate on which trucks were the best. For the sake of this article, I will try and break down the discussion into several time periods to cover all the iterations of all the engines 12 in total between the three. Keep in mind, this article is more anecdotal than anything else, and you will have to draw your own conclusions.
(1986-1993) In all reality, the first engines didn’t put up any impressive figures initially. In 1989, the 12v 5.9 Cummins put up a mere 160 horsepower, but a respectable 400 ft-lbs. torque. The 7.3 International IDI put up 185 horse, and 338 ft. lbs. torque. Lastly, the 6.2 Detroit used by Chevrolet had 160 horse, with 285 ft. lb. torque. In the first generation of diesel engines, I will have to give the prize to the 5.9 just for the power available. Not only did it come with more power, it was much easier to supe-up than the other engines on the market. Reliability wise, they were all very good. There were a couple of notable issues, such as the “killer dowel pin” in the Cummins, the cylinder wall cavitation in the International, and the fact that the 6.2 would shake itself apart due to poor crankshaft balance. (1994-2002) Ford introduced the 7.3 Powerstroke engine in 1994, and it was an instant legend. Surpassing both Dodge and Chevy in sales, there are still 2 million of these trucks on the road today, 13 years after production ceased. This truck was known for good power output and reliability. While the 12v Cummins was still a good engine, not much had changed about it. Chevrolet had switched over to the 6.5 Detroit, which did have a little more power output, but still lagged behind the others. Keep in mind, when Chevy came out with a diesel engine, it was to get better fuel economy, not necessarily more power. For the mid 90’s to early 00’s, the 7.3 Powerstroke still sits as king of the hill. That was bound to be shaken up at some point though.
(2003-2007) With new emission regulations coming down the pipe in the early 2000’s, manufacturers had to start updating these older engine systems. Dodge upgraded their injection system to be a high pressure common rail, this is after they doubled the valves in the engine to 24. [after 1998] Chevrolet partnered with Isuzu to come out with the now famous Duramax. Ford traded in the old 7.3 design for the new, improved (I use that word lightly) 6.0 Powerstroke.
Both Dodge and Chevy had some problems with this new, complicated injection system. The LB7 Duramax had many more problems, leading to a class action lawsuit, and eventually an extended warranty on the injectors. Speaking of class action lawsuits, how about that 6.0? The real problem with the 6.0 was that it wasn’t designed to work as well in the higher horsepower pickup truck market. The VT365 worked great in medium duty trucks and buses, but was tuned for a much lower power output. The 6.0 had a lot of power, but just wasn’t durable, between head gaskets, EGR coolers and injectors. Need some Stiction Eliminator? For the mid 2000’s Cummins is once again the “best” with the early Duramax in a close second.
(2008-2010) After 2007, emission regulations got even more stringent, causing vast overhauls by both Ford and Dodge. Ford finally switched over to common rail injection, with the International 6.4 engine this engine would only have a short 3 year run. Dodge made the switch to the ISB 6.7 engine, finally putting the trusty 5.9 Cummins to rest interesting fact, the 6.7 uses about 40% of the parts the original 5.9 used. The transition was made pretty easily by the Duramax lineup, making it my favorite from this time period, unlike the Powerstroke, [which was very, very different and complicated]
(2011-present) 2011 brought us EVEN MORE emissions regulations, leading to the use of DEF. Ford went to the drawing board for the first time to come up with their own diesel engine, breaking up their 25-year relationship with International. What they came up with was a compact graphite iron block, and a reverse flow engine. Reverse flow? Yes, the intakes are on the outside of the engine, with the exhaust coming out to the turbo in the engine valley. Other than a potentially deadly glow plug issue on the first run of engines, they are very reliable. Dodge still uses the 6.7 engine, and Chevy has the 6.6 Duramax. The Duramax has adapted to every new regulation almost seamlessly, other than a few cold weather DEF issues. They currently sit at last place on listed power output but not by much.
I really can’t say which engine is best, being a Ford guy, I will lean towards the Scorpion engine, I mean how cool is that name? But all the engines have immense power, and towing capability. If you are looking for a new truck, I would base a decision off of aesthetics and personal preference. You really are not going to go wrong with any American 1-ton truck manufactured today. I don’t see any trucks sticking out until they reach 1,000 ft-lb. torque, which isn’t that far off, seeing as we have two trucks over 800 ft. lbs.
Originally published in LSI Innovation Magazine – Issue 104