Cummins 4934391 Timing Gear Housing Assembly

The Cummins 4934391 timing gear housing is a cast iron front cover assembly designed to enclose the engine timing gear train and provide mounting for the fuel injection pump. It supersedes part numbers 3917759, 3960071, 3802350, and 3920758. This housing is configured for rotary (VE) and inline (P-pump) fuel systems on 4-cylinder and 6-cylinder B-series engines. The component features precision-machined mounting faces for the crankshaft front seal, camshaft thrust plate, and fuel pump flange. It includes passages for lubrication oil feed to the timing gears and idle shaft. The raw casting is typically supplied with a protective primer coating. It serves as a direct replacement for OEM gear housings on Cummins B3.3, B3.9, and B5.9 engine platforms used in on-highway trucks, construction machinery, agricultural equipment, and generator sets.