It is especially important to check engines with a long service life.
Worn valve guides do not maintain valve seat centricity and lead to increased oil consumption. If wear is excessive, replace valve guides (repair shop job).
1. Remove the valve.
2. Clean the valve guide (1/2) cylindrical brush (diameter about 20mm).
3. Insert the valve from the side of the combustion chamber into the guide and check the gap by moving the valve sideways back and forth. In this case, there should not be a noticeable gap. (1 - exhaust valve guide, 2 - intake valve guide, and - circlip.)
4. Replace valve guides if necessary (repair shop job).