Cummins/Onan P2400 / P3500 — Valve Clearance
Adjustments · Cylinder head / valves
For the Cummins/Onan P2400 / P3500, from the Cummins/Onan service manual.
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Procedure
- Remove the valve cover and set the piston at top dead center of the compression stroke (both valves fully closed).
- Insert a feeler gauge between the rocker arm and valve to measure valve clearance.
- If adjustment is necessary, hold the rocker arm pivot and loosen the pivot lock nut.
- Turn the rocker arm pivot to obtain the specified clearance.
- Retighten the lock nut while holding the rocker arm pivot.
- Recheck valve clearance after tightening the lock nut.
Tools required
- Feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Standard Valve Clearance IN: 0.15 ±0.02 mm (0.006 ±0.001 in)
- Standard Valve Clearance EX: 0.20 ±0.02 mm (0.008 ±0.001 in)
- Must be performed with the engine 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.