Westerbeke 8.0KW-60Hz Service Manual page 25

ENGINE-DISASSEMBLY, INSPECTION AND ASSEMBLY
VAlVE SEAT REPLACEMENT
1. Cut the valve thickness to be replaced from the inside to
reduce
the wall thickness. Then, remove the valve seat.
2. Rebore the valve seat hole in the cylinder head to match
the selected oversize valve seat diameter.
INTAKE VALVE SEAT HOLE DIAMETERS (0.3 ov ...
lz.)
PRIMARY 27.300· 27.325mm (1.075 ·1.07610)
SECONDARY 32.300· 32.325mm (1.272 ·1.27310)
INTAKE VALVE SEAT HOLE DIAMETERS (0.6 ov ...
lz.)
PRIMARY 27.600· 27.625mm (1.087 ·1.08810)
SECONDARY 32.600· 32.625mm (1.284 -1.2810)
EXHAUST VALVE SEAT HOLE DIAMETERS (0.3
ove .. lz.)
35.300· 35.325mm (1.390 ,1.39110)
EXHAUST VALVE SEAT HOLE DIAMETERS (0.6
ove .. lz.)
35.600 • 35.625mm (1.402 • 1.40310)
3.
Prevent galling of the cylinder head bore by cooling the
valve seat with liquid nitrogen before press-fitting it.
4. Correct
the valve seat to achieve the specified width and
angle.
CUTAWAY
VALVE SEAT
1"'<""-:- " •• -
1.0mm
Oversize hole I. D.
VALVE GUIDE REPLACEMENT
1.
Using a press, push the valve guide out toward the
cylinder block side.
2.
Rebore the valve guide hole in the cylinder head to match
the oversize valve guide that is to be fitted.
A
CAUTION:
Da nIt install a valVII guide If the same
_again.
VALVE GUIDE HOLE DIAMETERS
0.05 OVERSIZE: 12.050 • 12.068mm (.474 - .47510)
0.25 OVERSIZE: 12.250 -12.268mm (.482 - .48310)
0.50 OVERSIZE: 12.500 -12.518mm (.4925 •• 493210)
3. Press-fit the valve guide until it projects by the specified
amount
PROJECTION
A
CAUTION:
The valve guide must be installed frllm
the upper side If the cylinder head.
The valve guides differ in length on the intake and
exhaust sides.
After press·fitting the valve guide, insert
a
new valve
and check that it slides smllllthly.
VALVE STEM SEAL INSTALLATION
1.
Install the valve spring seat.
2.
Install a new valve stem seal using the special tool shown.
A
CAUTION:
Valve stem seals cannllt be re·used.
New valve stem seals must be Installed using the
cllrrect special tIll. Incorrect Installatilln clluld result
in Iii leaking past the valve guide_
VALVE SPRING INSTALLATION
STEM
SEAL
1.
Install the valve spring with the painted end on the rocker
arm side.
COATED
SIDE
RETAINER
VALVE STEM
'-'--.:ro
~"'--
SEAL
_.....fh~::::'::]d.c::::::SI1RING
SEAT
'tii'Y'
WESTERBEKE
Engines
&
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