Komatsu Diesel Engine 3D72-2, 3D75-2, 3D78-1, 3D84-2, 3D84N-2, 4D84-2 Shop Manual (P/N SEBM002400)

• Covers Komatsu 3D72-2, 3D75-2, 3D78-1, 3D84-2, 3D84N-2, and 4D84-2 series engines. Also includes variant TN-series specifications such as 2TN66E, 3TN66E, 3TNA72E, 3TN75E, 3TN82E, 4TN82E, 3TN84E, and 4TN84E.
• Original OEM publication (P/N SEBM002400, published November 1993). Serves as the primary source for factory assembly and inspection standards.
• Contains 12 exploded-view diagrams for fuel injection equipment and 15 detailed specification tables for engine components.
• Streamlines shop workflows by providing exact factory tolerances and measurement procedures directly to the technician's workbench.

Engine Service Documentation

This technical reference details the structural and functional characteristics of the 72-2 through 84-2 engine families. Mechanics will find comprehensive breakdowns of basic engine construction. The text outlines cylinder block inspection, cylinder head maintenance, piston and pin sizing, connecting rod alignment, and crankshaft balancing. Timing gear configuration is also heavily detailed. The documentation breaks down lubrication and cooling systems through clear structural overviews, supporting professional-grade assembly and teardown work. Safety remains a critical factor when handling heavy diesel components. Always follow established workshop safety guidelines and consult a certified technician before executing heavy structural maintenance or high-pressure fuel system adjustments.

Technical Specification Highlights

Precise data drives accurate engine builds. The manual defines maintenance standards for all essential wear limits. Valve clearance for intake and exhaust valves is firmly documented at 0.2 mm across the listed series. Cylinder head bolt torque values follow a strict multi-stage sequence. Final-stage values reach 7.5–8.5 kg-m specifically for the 4TN84E and 4TN84TE variants. Standard injection pressure sits at 19.61 MPa (2844 PSI) for the majority of the direct-injection models. Fuel injection system documentation further covers YPES and YPFR pump types. It outlines governor construction, adjustment parameters, and precise testing procedures. Finally, testing and adjusting data sections deliver reference charts for verifying engine timing, output metrics, and injection pressure.