Cummins/Onan P9500df — Checking and Adjusting Valve Lash
Adjustments · Engine
For the Cummins/Onan P9500df, from the Cummins/Onan operator's manual.
Applies to: Cummins/Onan P9500df
Before you start
- Must be done when engine is cold
Procedure
- Remove rocker arm cover and carefully remove gasket, replace if torn or damaged
- Remove spark plug so engine can be rotated more easily
- Rotate engine to top dead center (TDC) of compression stroke
- Confirm both rocker arms are loose at TDC on compression stroke; if not, rotate engine 360 degrees
- Insert feeler gauge between rocker arm and push rod to check clearance
- If adjustment required, hold adjusting nut and loosen jam nut
- Turn adjusting nut to obtain correct valve lash
- Hold adjusting nut and tighten jam nut to 106 in-lb (12 N.m)
- Recheck valve lash after tightening jam nut
- Perform for both intake and exhaust valves
- Install rocker arm cover, gasket 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
- {'item': 'jam nut torque', 'value': '106 in-lb (12 N.m)'}
- {'item': 'intake valve lash', 'value': '0.0035 ± 0.0043 in (0.09 ± 0.11 mm)'}
- {'item': 'exhaust valve lash', 'value': '0.0043 ± 0.0051 in (0.11 ± 0.13 mm)'}
Full service-parts list: Cummins/Onan P9500df →
Source: Cummins/Onan operator'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.