6.7 liter Cummins vs. 6.7 liter Power Stroke diesel engines: what are the differences? – Jalopnik

If you ever want to start a discussion among diesel enthusiasts, just bring up the subject of the 6.7 Cummins and PowerStroke diesel engines and watch the sparks fly. It’s a rivalry as old as time itself. Both the 6.7-liter Cummins turbodiesel and Ford Power Stroke engines are titans in the diesel world, known for their massive torque, pulling power and loyal fan following. One is an Indiana-born straight-six that’s essential in Ram trucks, while the other is Ford’s beloved V8 seen in its Super Duty pickups. On paper they have some similarities, but there isn’t much besides their movements.

The Cummins 6.7-liter turbodiesel was introduced in 2007 as a replacement for the 5.9-liter turbodiesel that was a favorite among Ram pickups. You’ll even find it under the hood of the 2027 Ram Power Wagon, an all-terrain vehicle with a diesel engine. The 6.7 shared the rugged cast iron block of the 5.9, but featured performance improvements and longer service intervals. The engine was updated in 2013, increasing torque and improving fuel economy by 10%. In 2019, the fifth-generation Ram HD received a new engine block made of lighter compressed graphite iron and an updated fuel management system, pushing peak torque to more than 1,000 pound-feet.

The Ford 6.7-liter Power Stroke engine, meanwhile, was introduced in 2011 as a replacement for the 6.4-liter Navistar engines. This was Ford’s own V8, codenamed “Scorpion” and featuring its own compressed graphite iron block in addition to Bosch high-pressure fuel injection. Today, the engine produces nearly 1,200 pound-feet of torque.

The Ford PowerStroke is a V8 turbodiesel with four cylinders on each bank and a shorter crankshaft. It is also a lot more complex than the Cummins. The engine has a reverse-flow header design, which is different from a traditional V8. The latter has the exhaust manifold on the outside of the engine banks, while the Ford has the exhaust gases from the valley of the engine, directly into the turbocharger. This reduces turbo lag and makes the engine quite responsive. While both engines use compacted graphite iron cylinder blocks, the Cummins uses a traditional cast iron cylinder head, while the Power Stroke uses lighter aluminum cylinder heads.

Peak power and torque only tell part of the story. The Cummins engine delivers its torque over a wider speed range thanks to the inline six-cylinder engine and turbo setup. This allows it to effortlessly pull heavy loads even on steeper slopes, while the Power Stroke does this with brute force. Peak power is delivered at a slightly higher rpm with a more aggressive power delivery, especially in the High Output engine configuration. However, when it comes to the real world, both engines deliver. With its extra torque, the Power Stroke has a slight edge when it comes to maximum power, but that doesn’t stop people from loving the Cummins alternative.

The early 6.7 Power Stroke engines had some teething problems with their high-pressure fuel pumps and turbochargers. (According to owners, these are the worst years for the Ford 6.7 Power Stroke.) These engines have always used Bosch CP4.2 pumps, which were known for their aversion to poor quality fuel. The newer generation of Power Stroke engines (from 2015) solved most of these problems and featured improved durability and reliability. In terms of serviceability, the layout of Ford’s V8 engine limits easy access to certain areas. But compared to Cummins, Ford’s vast dealer network means you can find help even in the most remote regions.

While real-world feedback helps push Cummins forward in terms of durability, modern Power Strokes are also quite reliable. Diesel forums indicate that both engines will exceed the 300,000 mile mark, provided they are properly maintained. Under normal use, most users won’t even reach the point where they put any strain on these motors anyway. All they require is emissions-related maintenance, such as periodic DPF rains and EGR cooler cleaning.

In terms of fuel economy, the Cummins engine offers relatively less miles per gallon when towing heavy loads. This isn’t as bad as it sounds, as some Cummins engines can even run on biodiesel. But the 6.7 Power Stroke offers better fuel economy when driving in loaded conditions and on the highway.

As for the driving experience, the Cummins’ engine layout gives it an old school diesel note, while the Ford’s V8 configuration emits a rumbling growl. With their emissions control systems removed, you would notice that the Cummins sounds like an old-fashioned tractor, while the Power Stroke sounds like a jet engine. Overall, both engines are towing champs, but the Cummins rigs feel like real work trucks, while the Power Stroke trucks feel like performance vehicles.

By comparison, the 6.7 Ford Power Stroke feels like an extra capable beast when you consider speed, smoothness and integrated technology. Compared to the raw, rugged character of the Cummins engine, the Ford V8 is quieter and more advanced. The V8 diesel engine, mated to the 10-speed gearbox, makes for a ridiculously fast ride, and when it comes to towing, it’s an effortless experience, too.

While the Cummins feels like the Old Testament of diesel engines, the Ford Power Stroke feels like the future. If you’re looking for a proven workhorse, the Cummins-powered Ram is your best bet. If you want a fast pickup that can also tow houses when necessary, the Ford Super Duty is for you, even with its other attractive engine option, the 7.3-liter gas-powered Godzilla V8.