Valve Seats

Fig 1: Valve Face & Seat

Courtesy of CHRYSLER GROUP, LLC

1 - SEAT WIDTH

2 - FACE ANGLE

3 - SEAT ANGLE

4 - SEAT CONTACT AREA

NOTE:

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

Measure the concentricity of the valve seat using a dial indicator. Refer to SPECIFICATIONS .
Inspect the valve seat (3) with Prussian blue to determine where the valve contacts the seat. To do this, coat the valve seat (3) LIGHTLY with Prussian blue then set the valve in place. Rotate the valve with light pressure. If the blue is transferred to the center of the valve face (4), contact is satisfactory. 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.
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.
When the seat is properly positioned the width of the intake and exhaust seats should be within specification. Refer to SPECIFICATIONS .