Seat Contact Width

Grind the valve seats to a true 45-degree angle. Remove only enough stock to clean up pits and grooves or to correct the valve seat runout. After the seat has been refaced, measure valve seat contact width. Use a seat width scale or a machinist scale to measure the seat width. Narrow the seat, if necessary, to bring it within specification.
If the valve seat width exceeds the maximum limit, remove enough stock from the top and/or bottom edge of seat to reduce the width to specifications.





Engine intake and exhaust seats use a 60-degree angle grinding wheel to remove stock from the bottom of the seat (raise the seats). A 30-degree angle wheel is used to remove stock from the top of the seats (lower the seats).
On the intake and exhaust seats, use a 60-degree angle grinding wheel to remove stock from the bottom of the seats (raise the seats). A 30-degree angle wheel is required to remove stock from the top of the seats (lower the seats).