Checking the valve guides

In the case of repair work on a cylinder head with leaking valves, it is not enough to finish or replace the valves and valve seats. The valve guides need to be checked for wear. This check is most necessary on engines with a long service life. Worn valve guides do not center the valve seat, resulting in high oil consumption. If the guides are worn too much, the valve guides must be replaced (work being done in the workshop).

Remove the valve.

Clean the valve guide with pipe cleaner.



Insert the valve into the guide and check the valve clearance by rocking it back and forth. The valve must not have any appreciable clearance.

Engine	Permissible clearance in mm
	intake valves	exhaust valves
Four-cylinder petrol	0.020 - 0.069	0.046 - 0.095
Diesel	0.03 - 0.07	0.04 - 0.08

Measure the gap using improvised means: lay a steel square on the cylinder head and valve. Rock the valve back and forth and measure the clearance with a gauge.

Using an appropriate reamer, countersink the valve guide to the following upper dimension limit (work being done in the workshop), always start from the combustion chamber only.

Attention! If you countersunk the valve guides, then you must install valves whose stem meets the upper size limit.