4BT Cummins

3.9L Cummins 4BT Specs, History, & Information

The Cummins 4BT is essentially a 5.9L 12v Cummins minus two cylinders. This 3.9L, 4 cylinder, inline diesel was commonly used in commercial van applications (popular application for Chevy Step Vans - think bread delivery trucks), as well as a variety of construction and agricultural equipment. Generous amounts of torque in a small package make the 4bt common for engine swaps in Jeeps & small trucks/SUVs.

The 4BT is dimensionally similar to the 6BT, save for a much shorter length. The pistons, injectors, connecting rods, and valvetrain design are straight off of the 12v Cummins. Because inline 4 cylinders are not inherently balanced like inline 6 cylinder engines, the engine is noticeably harsher than its larger brother. The engines can be found in applications with up to a 16,000 lb GVWR, which should serve as a limit for anyone whom plans to use the engine in a custom application.

 

4BT Cummins Specs

Configuration:

Inline 4 cylinder

Displacement:

3.9 liters, 239 cubic inches

Bore x Stroke:

4.02" x 4.72"

Cylinder Head Material:

Cast iron

Engine Block Material:

Cast iron

Firing Order:

1-3-4-2

Compression Ratio:

17.5 : 1

Injection:

Direct injection, mechanical injection pump

Aspiration:

Turbocharged, non-intercooled

Valvetrain:

OHV, 2 valves per cylinder

Weight:

745 - 782 lbs w/ oil

Oil Capacity:

10 quarts

Governed Speed:

Varies with application

Horsepower:

105 hp @ 2,300 rpm *

Torque:

265 lb-ft @ 1,600 rpm *

* Common rating, output may vary considerably with application.

4BT Cummins Dimensions

Length

Width

Height

30.6"

24.6"

37.7"