Cummins/Onan 3.6MKY / 4MKY — Valve Clearance Adjustment
Adjustments · Valve system
For the Cummins/Onan 3.6MKY / 4MKY, from the Cummins/Onan service manual.
Applies to: Cummins/Onan 3.6MKY, Cummins/Onan 4MKY
Before you start
- Adjust the valve clearance only when the engine is at ambient temperature.
Procedure
- Remove the head cover and inspect valve stems for alignment with the rocker arms.
- Advance the engine until both valves are closed (piston at top dead center).
- Check clearance with a feeler gauge between the top of the valve stem and rocker arm.
- Loosen the outer locking nut and turn the adjusting nut to obtain the correct clearance.
- Tighten the locking nut after adjustment.
- Recheck the clearance and check the rocker arm bolts have not loosened.
- Reinstall the head cover and torque the bolts to specification.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake 0.002 inch (0.05 mm) cold
- Exhaust 0.002 inch (0.05 mm) cold
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.