Table of Contents
Advertisement
CAUTION
Do not grind valve to shorten. Grinding will remove the
case hardening and expose the stem's mild steel core
resulting in rapid end wear.
8.
See
Figure 3-22.
Wipe valve seats and valve faces clean.
Measure valve stem protrusion. If valve stem protrudes
more than 2.034 in. (51.66 mm), replace valve seat or
cylinder head. If valve stem protrusion is within the
acceptable range, valves and seats are ready for lapping.
Replacing Valve Seats
Replacing a valve seat is a complex operation requiring spe-
cial equipment. If the seat is loose or is not fully seated in the
head, then seat movement will prevent the proper transfer of
heat from the valve. The seat surface must be flush with (or
below) the head surface. See
seat-to-cylinder head fit.
To remove the old seat, lay a bead of weld material around
the inside diameter of the seat. This will shrink the seat out-
side diameter and provide a surface for driving the seat out
the port side.
Lapping Valve Faces and Seats
Apply a light coat of fine lapping com-
1.
See
Figure 3-23.
pound to valve face. Insert valve in guide. Position one
rubber cup end of
VALVE LAPPING TOOL (Part No. HD-
96550-36A)
onto head of valve. Holding lapping tool as
shown, apply only very light pressure against valve head,
and rotate lapping tool and valve alternately clockwise
and counterclockwise a few times.
2.
Lift valve and rotate it about 1/3 of a turn clockwise.
Repeat lapping procedure in Step 1.
3.
Repeat Step 2. Then, remove valve.
4.
Wash valve face and seat; dry with a new, clean cloth or
towel.
5.
If inspection shows an unbroken lapped finish of uniform
width around both valve and seat, valve is well seated. If
lapped finish is not complete, further lapping (or grinding
and lapping) is necessary.
3-18
SPECIFICATIONS
for valve
www.PlanDeGraissage.org
5696
Valve stem must not protrude
more than 2.034 in. (51.66 mm)
Figure 3-22. Measuring Valve Stem Protrusion
5118
Cylinder Head Holding
Fixture (Part No. HD-39786)
Figure 3-23. Lapping Valves
Valve Lapping Tool
(Part No. HD-96550-36A)
Advertisement
Table of Contents
