Valve Seat

Valve seat





1. Inspect contact surface of each valve seat and valve face for following:
a. Roughness
b. Damage
c. Pitting
d. Cracks





2. Resurface valve seats with a 45° valve seat cutter. Resurface valve faces as needed.
3. Apply a coat of Dychem blue to valve face and valve seat and allow to dry.
4. Inspect valve seating by pressing valve against seat and rotating valve 360°.
a. If Dychem blue is not removed 360° around valve face, replace valve.
b. If Dychem blue is not removed 360° around valve seat, resurface valve seat.





5. Measure seat contact width.
Width: 0.078 - 1.059 inch (1.98 - 2.69 mm)





6. Check that valve seat contact area is at center of valve face.
a. If valve seating position is too high, correct valve seat with a 63° valve seat cutter, and a 45° cutter.
b. If seating position is too low, correct valve seat with a 0° and a 45° cutter.
7. Complete seat-cutting process by lapping valve to seat using valve-lapping compound.





8. Inspect valve seat for sinking.

Notice: Clean valves thoroughly before reassembly, and insure that all traces of lapping compound have been removed.





9. Check for valve sink by measuring protruding length (Dimension L) of valve stem to lower valve spring seat.
Dimension L measurement:
Action: No correction needed
IN: 1.432 - 1.467 inch (36.37 - 37.27 mm)
EX: 1.431 - 1.467 inch (36.36 - 37.26 mm)
Action: Adjust with washer on spring seat area of cylinder head
IN: 1.467 - 1.495 inch (37.27 - 37.97 mm)
EX: 1.467 - 1.494 inch (37.26 - 37.96 mm)
Action: Replace the cylinder head
IN: 1.495 inch (37.97 mm)
EX: 1.494 inch (37.96 mm)