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CYLINDER HEADN ALVES
The valves cannot
be
ground.
If the
valve face is
burned,
badly worn
or
if
it conta
cts
the
seat
unevenly,
repla ce the valve.
10-18
While the cylinder head is still heated
,
take off a new
valve guides [1) from the
freezer.
Adjust the valve guide driver to the valve guide height
and drive in the valve guide from the camshaft side.
TOOL:
Valve guide driver [2]
077 43-0020000
SPECIFIED HEIGHT:
IN/EX: 13.8 - 14.0 mm (0.54 - 0.55 in)
Let the cylinder head cool to room temperature.
Ream a new valve guides.
TOOL:
Valve guide reamer,
4.5 mm [1]
NOTE:
07HMH-ML00101 or
07HMH-ML001
OB
(U.S.A. only)
• Use cutting oil on the reamer during this operation
.
• Take care not to tilt or lean the reamer in the guide
while reaming. Otherwise
,
the valves may be
installed slanted, causing oil leakage from the stem
seal and improper valve seat contact. This may
prevent valve seat refacing
• Insert the reamer from the combustion chamber side
of the head and always rotate the reamer clockwise.
~
e
[1]
[1]
[2]
Clean the cylinder head thoroughly to remove any metal particles after reaming and reface the valve seat (page
10-18).
VALVE SEAT INSPECTION/REFACING
INSPECTION
Clean the intake and exhaust valves thoroughly to
remove carbon deposits.
Apply a light coat of Prussian Blue to the valve seats.
Tap the valve against the valve seat several times using
a hand-lapping tool [1), without rotating the valve to
make a clear pattern.
Remove the valve and inspect the valve seat face
.
The valve seat contact should be within the specified
width and even all around the circumference.
STANDARD:
0.90-1.10 mm (0.035- 0.043 in)
SERVICE LIMIT: 1.50 mm (0.059 in)
If the valve seat width is not within specification
,
reface
the valve seat (page 10-19).
Inspect the valve seat face
for:
• Damaged face
:
- Replace the valve and reface the valve seat
• Uneven seat width
:
(1]
- Bent or collapsed valve stem
;
Replace the valve and reface the valve seat
• Contact area (too low or too high):
- Reface the valve seat
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