Valve Seat: Service and Repair

Valve seats, refacing

Special tools and equipment

- Depth gauge
- Valve Seat Refacing Tool

Procedure

Notes:

- When servicing engines with leaking valves, refacing or replacing valve and valves is not sufficient. It is particularly important to check valve guides for wear on engines with longer running times.
- Only reface valve seats enough until perfect contact pattern is obtained. Before refacing, determine maximum refacing dimension. If refaced dimension is exceeded, hydraulic valve lifter function is no longer guaranteed and cylinder head must be replaced.
- Refer to Camshafts, removing.

Maximum permitted refacing dimension is calculated as follows:

- Insert valve and press tightly against valve seat.

Note:

- If valve is replaced during repair, use new valve for measurement.






- Measure dimension -a- between valve stem tip and upper edge of cylinder head.
- Calculate maximum allowable refacing dimension using measured distance -a- and minimum dimension.

Minimum dimensions:

- Short Intake Valve mm 31.8

- Long Intake Valve mm 10.2

- Short Exhaust Valve mm 31.8

- Long Exhaust Valve mm 10.2

Distance measured minus minimum Dimension = maximum allowable refacing dimension.

Example:

Distance Measured 10.6 mm

Minimum Dimension 10.2 mm

=Maximum Allowable Refacing Dimension 0.4 mm

Maximum allowable refacing dimension is represented in illustrations for refacing valve seats as dimension "b".

Refacing Valve Seats

Refacing Intake Valve Seat Dimensions:

Refacing Exhaust Valve Seat Dimensions: