69M3E11 5-201234567897. If the valve seat contact area is too nar-row and situated near the top edge of thevalve face, use a 30° cutter to cut the topedge of the valve seat. If necessary, usea 45° cutter to center the area and set itswidth.b Previous contact width8. If the valve seat contact area is too nar-row and situated near the bottom edge ofthe valve face, use a 60° cutter to cut thebottom edge of the valve seat. If neces-sary, use a 45° cutter to center the areaand set its width.b Previous contact width9. Apply a thin, even layer of lapping com-pound onto the valve seat, and then lapthe valve using a valve lapper (commer-cially obtainable).CAUTION:Do not get the lapping compound on thevalve stem or valve guide.10. After every lapping procedure, be sure toclean off any remaining lapping com-pound from the cylinder head and thevalve.11. Check the valve seat contact area of thevalve again.Checking the cylinder head1. Eliminate carbon deposits from the com-bustion chambers and check for deterio-ration.2. Check the cylinder head warpage using astraightedge 1 and thickness gauge 2in six directions as shown. Replace if outof specification.S69M5390Cylinder head warpage limit:0.1 mm (0.004 in)S69M542021S69M5430Cylinder head
