Cummins/Onan — Engine General Assembly
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MCCK
Before you start
- During assembly, turn engine over by hand — should turn over freely.
- Coat all internal parts with oil.
Procedure
- Install new main bearings if required, using proper bearing driver.
- Install crankcase and rear bearing plate; check end play.
- Install pistons, rods, bearings and rod caps.
- Install crankshaft and timing gear assembly.
- Install oil pump and oil base.
- Install crank gear aligning timing mark with mark on camshaft gear.
- Install valve assemblies and cylinder heads.
- Install gear cover and oil seal.
- Install flywheel.
- Install fuel pump, manifold assembly, air cleaner, fuel lines, spark plug, breaker box, etc.
- Connect electrical wires, exhaust line and battery.
- Fill crankcase with proper oil.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan MCCK →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.