Valve Guide Inspection

When repairing a cylinder head with leaking valves, it is not sufficient to only machine the valves and seats or replace them. In addition, the valve guides must be inspected for wear. This is especially important on high-mileage engines. Worn guides prevent proper valve seating and cause increased oil consumption. If wear is excessive, replace the guides with new ones (workshop operation).

PROCEDURE
1. Remove the valve.
2. Remove deposits from the guide.
3. Insert a new valve from the combustion chamber side. The end of the stem must be enclosed by the guide.
4. Check the clearance in the fit by rocking the valve.

5. To check the valve clearance, place a dial indicator or steel rule against the valve. The maximum clearance must not exceed 0.5 mm.
6. If the clearance is greater, ream the valve guides and install oversize valves with larger stem diameter (workshop operation).

* If the guide was replaced or reamed, the valve seat must be machined.