The 3.9L/4B is an inline four-cylinder naturally aspirated or turbodiesel that was popular for many step van applications, including bread vans and other commercial vehicles. The 3.9L/4BT Cummins is an engine in the same family as the 5,883 cc (5.9 L 359.0 cu in) Cummins diesels.
The original B Series was updated with 24 valves and an electronic engine management system to become the ISB in 1998.ĥ.9 Cummins in 1991 Dodge Ram with the valve covers removed exposing the valvetrain 3.9L/4BT Also specified is a deep-skirt engine block and extra-strong connecting rods. It uses a gear-drive camshaft for extra reliability. Įvery Cummins powered Dodge Pickup (since initial production in 1989) has come equipped with a turbocharger. The engine was first manufactured in Rocky Mount, North Carolina, and other plants were later added in Mexico, Turkey, and Darlington, UK. It was also set apart by the use of a shallow one-piece head, requiring closer tolerances than in other Cummins products. The B-series features engine bores machined directly into the block (rather than the wet liners used on earlier Cummins engines).