Cummins/Onan — Valve Adjustment (V/VT-378, V/VT-504, V/VT-555)
Adjustments · Valves
From a Cummins/Onan owner's manual covering: KT38, KTA19, Kt19, KtA38, KtA50, N-855, NH-672, NH-743, NH-855, NT-855, NTA-855, NTC-270…. Check it applies to your exact model before use.
Applies to: Cummins/Onan Kt19, Cummins/Onan KTA38, Cummins/Onan KTA50
Before you start
- Be sure the injector and valve set markings are in proper alignment with the indicator mark.
Procedure
- Loosen the locknut and back off the adjusting screw.
- Insert a feeler gauge between the rocker lever and the top of the crosshead.
- Turn the screw down until the lever just touches the gauge.
- Lock the adjusting screw in this position with the locknut and torque to specification.
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 0.012 inch [0.30 mm] cold
- Exhaust valve clearance 0.022 inch [0.56 mm] cold
- Locknut torque 40 to 45 ft-lbs [54 to 61 N·m]; 30 to 36 ft-lbs with ST-669 Amazon eBay $204.59
Full service-parts list: Cummins/Onan Kt19 →, Cummins/Onan KTA38 →, Cummins/Onan KTA50 →
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.