If you’re a truck driver and haven’t been living under a rock since the 1980s, there’s not an iota of possibility that you haven’t heard of Cummins. The US-based engine manufacturer is popular for its diesel engines, but did you know that it’s got an equally wide range of applications elsewhere as well? In this article, we’ll take a look at the product portfolio offered by Cummins and throw some light on what its automotive products can mean for you, if you’re looking at picking a new or used diesel-powered truck.

From agriculture to drilling, from defence to construction, and from marine to heavy-duty automotive work, there’s a chance that if there’s a diesel engine involved, you have a Cummins offering available. Currently, for everyday automotive use, Cummins has its well-revered 6.7 liter diesel engine. In the latest version, it can produce up to 1000 lb-ft of maximum torque. That’s not a testament only to engineering and advancements in the field, but also a clear indication that your work truck is now much more capable than it used to be.

So how did it start, you must wonder. Back in the 1980s, Cummins and Chrysler came together to offer the latter’s customers a diesel-engined truck that not only turns out to be as usable as others but also more economical as well. This was backed by longevity and a brand appeal that has only been cemented over the years. In the year 1989, Dodge introduced to its range Cummins-powered diesel RAM trucks. These came with a 5.9-liter inline-six engine that made about 160 hp and 400 lb-ft. That was the 6BT engine, possibly the most famous from the Cummins range made for the RAM pickups. The 12-valve engine continued on till 1998, replaced by another 5.9-liter unit, the ISB.

The 5.9 ISB was a 24-valve diesel engine and included quite a few updates in comparison to its predecessor. But some of the basics remained unchanged — it was still a cast-iron engine, and boasted identical bore and stroke as the 6BT. The power and torque also improved massively, over the years. The final iteration of the engine, that continued till 2007 made 325 hp and 610 lb-ft. Which even by today’s standards is far from paltry. But that didn’t stop Cummins from innovating. The result of which was the 6.7 Cummins. From 2007 onward, the company has supplied Dodge/RAM with the 6.7 liter Cummins engine for its pickups.

The 5.9 ISB was a 24-valve diesel engine and included quite a few updates in comparison to its predecessor. But some of the basics remained unchanged — it was still a cast-iron engine, and boasted identical bore and stroke as the 6BT. The power and torque also improved massively, over the years. The final iteration of the engine, that continued till 2007 made 325 hp and 610 lb-ft. Which even by today’s standards is far from paltry. But that didn’t stop Cummins from innovating. The result of which was the 6.7 Cummins. From 2007 onward, the company has supplied Dodge/RAM with the 6.7 liter Cummins engine for its pickups.

You can read more about the basic differences between the 5.9 and 6.7 here.

5.9 Cummins (Schematic of 5.9 Cummins Engine)

It remained a cast-iron unit, but came with a lot of improvements — making it not only more powerful and usable but also ensuring that the stricter emission norms don’t hold the company back. So it’s got EGR, DPF, among other relevant bits. It’s still an inline-six engine, with power and torque that can put many others to shame. It continues with the four-valve-per-cylinder OHV layout, but also benefits from a high-pressure fuel-injection system, and electronically controlled fuel pump, apart from the variable geometry turbocharger. The latter has made the 6.7 Cummins much more drivable, and has also introduced the turbo brake feature that can be extremely helpful while towing. As mentioned above, the engine comes tuned to produce up to 1000 lb-ft, straight out of the factory. While that depends on the truck you choose, overall the 6.7 Cummins has a wide variety of upgrades that can make it more powerful, including tuners; this guide here is a good starting point for those looking to find out more on tuners for the 6.7.

But even that’s not where the range of diesels offered by Cummins ends. The brand also ventured into making four-cylinder diesel engines. These shared mechanicals with the larger six-cylinder units that we just talked about, but were used in less load-intensive vehicles. These are also said to not be as balanced as the six-cylinder engines offered by Cummins, but can be a swap for existing project trucks. Another range of products offered by Cummins for smaller vehicles includes the ISF engines — smaller capacity units making about 170 hp at max. The benefits include low overall cost, less noise, and controlled emissions.

6.7 Cummins (Schematic of 6.7 Cummins Engine)

Other automotive applications served by Cummins include trucks and buses, heavy duty trucks, RVs and motorhomes, school buses, etc. Some of the popular engines for these include the B6.7, a 6.7-liter inline-six engine with power capped at around 360 hp and torque at 800 lb-ft. Like the 6.7 Cummins for trucks, you also get a VGT on this. Moving upward, there’s the Cummins L9. It boasts more power and torque, but also offers quieter operations. The maximum rated power figures from the factory are in the region of 450 hp and 1250 lb-ft.

But if your work requires something larger and more powerful, then the X12 and X15 should suffice. The X12 is claimed to be the lightest engine in its class, with some respectable power-to-weight figures. It’s not available for pickups but you can get one for your motorhome or heavy-duty truck. The maximum power figures are up to 500 hp and 1695 lb-ft. The X15 takes it all a level above. Cummins mentions that it’s the most popular heavy-duty engine in North America. And with a peak torque of over 2000 lb-ft and a maximum rated power of 605 hp, we see little that can question Cummins’ claim. Adding further to its capabilities (and thus popularity) is its impressive engine-braking horsepower — rated at up to 600 hp. 

More 6.7 Cummins Reviews – See our best:

More 5.9 Cummins Reviews – See our best: