Valve Seat: Service and Repair

MAXIMUM PERMISSIBLE VALVE SEAT REFACING DIMENSION





The maximum permissible valve seat refacing dimension is the difference between the actual distance measured at the cylinder head (arrow) and the specified minimum dimension.

NOTE: The illustration is used to show an example of the minimum dimension, it shows an engine other than the 2.8 liter V6.

- Insert valve and press tightly against valve seat.
- Measure distance between center of valve stem and upper surface of cylinder head (arrows).
Specified minimum dimensions
At intake valve: 33.8 mm (1.331 inch)
At exhaust valve: 34.1 mm (1.343 inch)

Example:
- Measured distance minus Minimum dimension (specified) equals Max. refacing dimension (valve and valve seat dimensions):

34.8 mm (1.370 inch)
- 34.1 mm (1.343 inch) _______________________
= 0.7 mm (0.027 inch)


REFACING INTAKE VALVE SEAT





a - Diameter: 39.2 mm (1.543 inch).
b - Maximum permissible refacing dimensions noted above.
c - Seat width: 2.0 mm (0.079 inch).
Upper correction angle: 30°.
Valve seat angle: 45°.
Z - Bottom surface of cylinder head.


REFACING EXHAUST VALVE SEAT





a - Diameter: 32.4 mm (1.276 inch).
b - Max. permissible refacing dimension noted above.
c - Seat width: 2.4 mm (0.094 inch).
Upper correction angle: 30°.
Valve seat angle: 45°.
Z - Bottom surface of cylinder head