Valve Seat: Service and Repair

Valve seats, refacing

Special tools, testers and auxiliary items required
^ Depth gauge
^ Valve seat refacing tool

Note:
^ When repairing engines with leaking valves, it is not sufficient to reface or replace valve seats and valves. It is also necessary to check the valve guides for wear. This is particularly important on high mileage engines.
^ Only reface valve seats enough until a perfect contact pattern is obtained. The maximum permissible refacing dimension must be calculated before work is carried out. If the reworking dimension is exceeded, the function of the hydraulic lifters can no longer be guaranteed and therefore the cylinder head should be replaced.

The maximum permissible refacing dimension is calculated as follows:
- Insert valve and press firmly against seat.

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





- Measure gap - a - vertically between tip of valve stem end and upper edge of cylinder head - 1 -.
- Calculate max. permissible refacing dimension from measured distance and minimum dimension.

Minimum dimensions: Outer intake valve 34.0 mm, center intake valve 33.7 mm, exhaust valve 34.4 mm

Measured distance minus minimum dimension = max. permissible reworking dimension.

Example:

Example:

Refacing intake valve seat

Refacing intake valve seat:

Refacing exhaust valve seat

Refacing exhaust valve seat: