Lapping valve seats (VW Passat B3)

With perfectly machined valve seats and new valves, lapping the valve seats in the cylinder head is not necessary.

Valves may only be lapped using fine-grained grinding paste. To perform the necessary rotational movements, a tool with a rubber suction cup, such as HAZET 795, is mounted on the valve plate. The formation of scratches on the seat chamfers during lapping is eliminated by frequently lifting and uniformly turning the valve.

Note: After lapping, the grinding paste must be carefully removed.

The appearance of the working surface during the grinding process can also be controlled using fuel: Insert the valve, fill the combustion chamber with fuel, the fuel should not flow out of the valve guide. Otherwise, repeat the grinding process.

The original text can be found at: www.VWManual.ru