
Product Descreiption
1. Basic Specifications
- Part Number: 3942764 (C3942764)
- Application: Cummins ISLE / QSL9 / 6L8.9 diesel engines
- Material: Alloy steel (20CrMnTi), heat‑treated
- Teeth: 78 teeth (typical for ISLE)
- Structure: Spur gear, 2 mounting holes, 1 keyway
- Weight: Approx. 2.5 kg
- Condition: OEM / aftermarket, new or remanufactured2. Installation Position
- Location: Front timing gear housing, engine front side
- Mounting: On the fuel injection pump drive shaft
- Drive Connection: Meshes with crankshaft gear and camshaft gear in the timing train
- Timing Requirement: Installed with timing marks aligned to ensure correct fuel injection timing
- 3. Function
- Power Transmission: Transmits rotational power from the crankshaft to the fuel injection pump
- Fuel Timing: Drives the fuel pump at a precise 1:2 crankshaft ratio for accurate injection timing
- Torque Transfer: Delivers consistent torque to maintain fuel supply pressure under all engine loads
- System Operation: Ensures the fuel pump delivers high‑pressure fuel (250–1800 bar) to the injectors




