Valve Seat Resurfacing

A valve seat not producing a uniform contact with the valve must be resurfaced. The valve seat must contact the center of the valve face and have a width of 1.0 to 1.4 mm (0.039 to 0.055 inch). The valve seat for both the intake and exhaust valves is machined to three different angles. The seat contact surface is cut to a 45 degree angle. The surface above the seat (closest to the combustion chamber) is cut to a 30 degree angle. The surface below the seat (furthest from the combustion chamber) is cut to 60 degree angle.





- If the seating is too high on the valve face, use 30 and 45 degree cutters to correct the valve seat.





- If the seating is too low on the valve face, use 75 and 45 degree cutters to correct the valve seat.
- After desired seat width and position are achieved, lap valve on seat in two steps; first with a coarse lapping compound and second with a fine compound, each time using a valve lapper.
- Clean valve and valve seat area using solvent after: lapping is finished.