Ram Cummins 6.7L Turbo Diesel I6

Ram Cummins 6.7L Turbo Diesel I6 — every model and year that used this engine (5 models, 2014–present), based on NHTSA VIN build data, with links to prices and reliability.

RAM HD legendary inline-six diesel.

6.7L · 6 cylinders · 100% of builds flagged turbo · seen in 5 models, 2014–2027

By the numbers

Output range 360–430 hp (median 370 hp). Diesel: 100%. Based on 1,501 decoded NHTSA VIN build sheets.

About this engine family

The Cummins B Series is a family of diesel engines produced by American manufacturer Cummins. In production since 1984, the B series engine family is intended for multiple applications on and off-highway, light-duty, and medium-duty. In the automotive industry, it is best known for its use in school buses, public service buses in the United Kingdom, and Dodge/Ram pickup trucks.

In detail

The B-series features engine bores machined directly into the block (rather than the wet liners used on earlier Cummins engines). It is also set apart by the use of a shallow one-piece head, requiring closer tolerances than in other Cummins products. Unlike earlier diesel engines the B-series Cummins used direct injection and did not need glow plugs for cold starting. The engine was first manufactured in Rocky Mount, North Carolina, and other plants were later added in Mexico, Brazil, Turkey, and Darlington, UK.

It uses a gear-drive camshaft for extra reliability. Also specified is a deep-skirt engine block and extra-strong connecting rods. A Holset turbocharger is used. The original B Series was updated with 24 valves and an electronic engine management system to become the ISB in 1998. The 3.9-liter 4B/4BT/4BTA Cummins is categorized under the B Engine family alongside the 5.9-liter 6B/6BT/6BTA Cummins diesel engines. The 3.9 is an inline four-cylinder, either naturally aspirated (4B) or turbodiesel (4BT/4BTA), which was popular for many step van applications including bread vans and other commercial vehicles.

Additionally it has seen broad usage in agricultural equipment. It has also gained popularity as an engine swap into smaller trucks and SUVs. The lowest powered, naturally aspirated 3.9-liter Cummins, the 4B, produces . This variant is most commonly found in equipment such as generators and wood chippers. The 4BT is one of two turbocharged variants of the 3.9L B-Series engine. It has two valves per cylinder for a total of eight.

The most common output of this variant is 105 horsepower. The 4BTA is turbocharged, and aftercooled with four valves per cylinder for a total of sixteen. The most common output of this variant is . The 5.9 L Cummins, also known as the "12-Valve" Cummins was the first member of the Cummins B-Series to be used in a light truck vehicle. The 6BT used Bosch fuel systems, injector, and VE rotary pump and P7100 inline injection pumps.

Some early 6BTs were supplied with CAV rotary pumps instead, before the Bosch system became the sole standard. This engine started life in 1984 designed as an agricultural engine, for use in Case agricultural equipment. After 1989, the 6BT engine was used in light duty, medium duty and select heavy duty trucks and buses. The 6BT engine has recently become very popular for use in repowering various vehicles. The 6B is the naturally aspirated version of the 6BT with a power output of at 2,500 rpm, a peak torque output of at 1,200 rpm, and a compression ratio of 19:1.

There were no OEM automotive applications for 6B engines. Appearing in the 1989–1998 Dodge Ram pickup truck, it became a popular alternative to the large gasoline V8 engines normally used in full-size pickup trucks, since it produced torque at low engine RPM, and achieved significantly better fuel mileage. Due to the direct fuel injection, the 6BT has no glowplugs. The 6BTA is Turbocharged, and aftercooled, with an air to water after cooler mounted on the intake.

Has a compression ratio of 16.5:1. The B6.7L is just a re-named version of the ISB 6.7L. Cummins renamed it to B6.7 instead of ISB6.7 most likely sometime around 2018 or 2019. The only real difference from the initial ISB engine is the change of emissions equipment over the years and the valve cover not does have that hump, do note some slight differences in power ratings. The B6.7 ended production in 2026, being replaced by the Cummins B7.2L.

The B6.7N and B6.7 octane variants will still be produced. The B6.7N is a CNG variant of the B6.7L/ISB6.7L. The B6.7L "Octane" is a version of the B6.7L diesel that can use Propane, or 87 Octane Gasoline as fuel. It is marketed to "have the power of diesel and the simplicity of gas". Engine production starts with model year 2027. The Cummins B7.2L was announced in March 2025 for production in 2026 or 2027. It is the evolution of the B6.7L, thus becoming the latest B-series engine.

Source: Wikipedia — Cummins B Series engine, CC BY-SA.

Models that used this engine

Model Years with this engine Fuel VIN builds seen
3500 2014–2027 Diesel 723
2500 2014–2027 Diesel 440
5500 2014–2027 Diesel 176
4500 2014–2027 Diesel 158

Engine usage derived from NHTSA VIN build data (displacement + cylinder configuration). Model links lead to prices, generations and reliability.

For sale with this engine