Valve Seat: Service and Repair

Valve seats, refacing




Calculating the maximum permissible refacing dimension
- insert valve and hold firmly against valve seat
- measure distance a between end of valve shaft and upper edge of cylinder head
- calculate refacing dimension b (see example) using the measured distance a (above) and:




Minimum dimension
If the measured distance a is smaller than the minimum dimension, the hydraulic valve lifter will not work and the cylinder head must be replaced




Intake valve seat, refacing
a - diameter 38.3 mm
b - maximum permissible refacing dimension
c - maximum 1.4 mm
- if necessary rework valve seat insert With 75° correction cutter
Z - cylinder head lower edge
A - 45° valve seat angle
B - 3O° upper correction angle
G - 75° lower correction angle




Exhaust valve seat, refacing
a - diameter 33.5 mm
b - maximum permissible refacing dimension
c - approximately 2.0 mm
- if necessary rework valve seat insert With 75° correction cutter
Z - cylinder head lower edge
A - 45° valve seat angle
B - 3O° upper correction angle