Cummins/Onan P4500iDF — Valve Clearance
Adjustments · valve train
For the Cummins/Onan P4500iDF, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan P4500iDF
Before you start
- Checking and adjusting valve clearance must be done when the engine is cold.
Procedure
- Remove the rocker arm cover and carefully remove the gasket.
- Remove the spark plug so the engine can be rotated more easily.
- Rotate the engine to top dead center (TDC) by pulling the recoil handle slowly.
- Both rocker arms should be loose at TDC on the compression stroke.
- Insert a feeler gauge between the rocker arm and valve stem to measure clearance.
- If adjustment is necessary, hold the rocker arm pivot and loosen the pivot adjusting nut.
- Turn the rocker arm pivot to obtain the specified clearance.
- Hold the pivot and re-tighten the pivot adjusting nut to the specified torque.
- Perform this procedure for the other valve.
- Install the gasket, rocker arm cover, and spark plug.
Tools required
- feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Intake valve clearance: 0.0031 – 0.0047 in (0.08 – 0.12 mm)
- Exhaust valve clearance: 0.0051 – 0.0067 in (0.13 – 0.17 mm)
- Torque: 8-12 N•m
- Pivot adjusting nut torque: 106 inch-pound (12 N•m)
Full service-parts list: Cummins/Onan P4500iDF →
Source: Cummins/Onan owner's 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.