Valve Seat Roundness Measurement Procedure

1. Measure the valve seat roundness using a dial indicator attached to a tapered pilot installed in the guide. The pilot should have a slight bind when installed in the guide.

IMPORTANT: A pilot of the correct size must be used. DO NOT attempt to force the pilot into the guide. Pilots with adjustable diameters to fit various size guides are not recommended. Valve guide damage could occur if an adjustable pilot is used.

2. Compare your measurement with the following specification:

Valve Seat Roundness Specification Maximum valve seat roundness:
^ 0.10 mm (0.004 in.)

3. If the valve seat exceeds the roundness specification, you must grind the valve and valve seat using the Valve and Seat Reconditioning Procedure.
4. If new valves are being used, the valve seat roundness must be within 0.05 mm (0.002 in.).