Valves, Grind In
Correct milling is usually adequate for providing a gas-tight valve seat. However, the seat quality can be further improved by also grinding in the valve cone.
Use only fine-grained pastes for grinding. Lubricate valve stem before grinding.
Grind in valves by rhythmically lifting valves and turning uniformly. Use commercially available valve grinding tool.
After grinding, carefully clean valve and valve seat.