Valve Seats, Refacing

Note:
- The valve seats should only be refaced just enough to produce a good seating pattern.
- Calculate the maximum permissible refacing dimension before refacing.
- If the refacing dimension is exceeded, the function of the hydraulic valve lifters can no longer be guaranteed and the cylinder head should be replaced.

Calculating maximum permissible refacing dimension
- Install valve and press firmly against valve seat.

Note: If the valve is to be replaced as part of a repair use a new valve for the calculation.





- Measure distance between end of valve stem and top surface of cylinder head.

Note: The illustration shows a 4-valve head.

- Calculate maximum permissible refacing dimension from measured distance and minimum dimension.





The measured distance minus the minimum dimension equals the maximum permissible refacing dimension.





Example

Note: If the measured distance is less than the minimum dimension, repeat the measurement with new valves, or replace the cylinder head.