Valve Seats

Courtesy of CHRYSLER GROUP, LLC

1 - Seat Width

2 - Face Angle

3 - Seat Angle

4 - Seat Contact Area

NOTE:

When re-facing the valve seats, it is important that the correct size valve guide pilot be used for the re-seating stones. A true and complete surface must be obtained.

Measure the concentricity of the valve seat using a dial indicator. Total runout should not exceed 0.050 mm (0.002 inch.) total indicator reading.
NOTE:
Valve seats which are worn or burned can be reworked, provided that the correct angle and seat width are maintained. Otherwise the cylinder head must be replaced.
Check the sealing of the valve(s) to the valve seat(s) on the cylinder head(s):
- Coat the valve seat LIGHTLY with Prussian blue.
- Install the valve into the cylinder head.
- Rotate the valve onto the valve seat using light pressure.
- Using care not to wipe the Prussian blue, remove the valve from the cylinder head.
- If the blue is transferred to the center of the valve face, contact is within specifications.
- If the blue is transferred to the top edge of the valve face, then lower the valve seat with a 15 degree stone.
- If the blue is transferred to the bottom edge of the valve face, then raise the valve seat with a 65 degree stone.
When the seat is properly positioned. The width of the intake seat should be 1.0-1.2 mm (0.04-0.05 in.) and the exhaust seats should be 1.41-1.61 mm (0.055-0.063 in.).