Lapping of valve seats

Even perfectly machined valve seats and new valves must be lapped together to achieve optimum sealing. This must be observed especially in a diesel engine.



You can grind the valves only with a fine-grained paste. To give the necessary rotational movements, install a rubber suction cup on the valve disc. Grooving of the valve seat can be avoided by frequently lifting the valve and rotating it evenly further during grinding.

Attention! Residues of grinding paste after the end of the lapping process must be carefully removed.

The quality of grinding is checked by the type of work surface using "prussian blue" or "zinc white", as well as with fuel. Loosely install the valves, fill the combustion chamber with fuel. Fuel must not flow to the valve guide. Otherwise, repeat the lapping process.