Lapping of valve seats (VW Transporter T4)

With perfectly machined valve seat rings and new valves, lapping of the valve seats in the cylinder head is not required.



1. Valves may be lapped only with fine-grained grinding paste. To rotate the valve, a rubber suction cup is installed on the valve plate. To avoid scratches on the surface of the seat, lapping must be done with uniform rotations with frequent valve lifts.

Caution! After lapping, carefully remove the grinding paste.

2. The quality of the grinding is checked by the contact patch and fuel: install the valves freely, pour fuel into the combustion chamber. Fuel should not leak through the valve guide. Otherwise, continue grinding.