Westerbeke 6.5 MCG Service Manual page 19

CYLINDER HEAD AND VALVES
Valve Stem and Guides
Measure the clearance between the valve guide, ana the valve
stem and , if the clearance exceeds the limit, replace the
valve guide or valve, or replace both.
MEASURING VALVE
STEM DIAMETER
VAlVE STEM TO VAlVE GUIDE CLEARANCE
Standard Intake 0.0008· O.OOZOin (0.02- 0.05mm)
EX!Iau:st 0.0026- 0.0033in {0.0050 - tUIOSSmm}
Umlt Intake 0.0039in (0.10mm)
Extlau:st 0.0059ln (0.15mm)
VALVE STEM OUTER DIAMETER
Staridani lnta.ke
Exhaust
0.2585 ·.0.25911n (6.565 • 6;58Dmm)
0.2571 • 0.2579in
(6;530-·
6.55Dmm)
Valve Seat Reconditioning
Before correcting the valve seat, check for clearance
be~een
the valve guide an(l the valve. replace the valve
gUide if necessary. ·
To recondition, use a valve and seat cutter and a pilot or a
seat grinder, repair so that the seat width and seat angle are
the specified configuration.
After
correction~
the valve and the valve seat should be
lapped with lapping COJilpound.
INSTALLATION
Valve Stem Seal
VALVE SEAT CONTACT WIDTH
.035 • .051 In [0.9 • 1.3 mmJ
Install the valve spring seat, then using the valve stem seal
installer, install a new stem seal to the valve guide.
Do not use the old valve stem seal.
NOTE:
Use the installer tool to insert the stem seal,' improper
installation can cause oil to leak into the cylinder.
17
VALVE STEM
SEAL INSTALLER
Valve .Springs
~
Install the valve spring with it's enamel coated side toward
the rocker ann side.
ENAMEL
COAT
EO
· SIDE
REMOVING
RETAINER
LOCKS
Cylinder Head Gasket
Clean the residue of gasket and oil from the gasket mounting
surface of the cylinder block and the cylinder head.
Place a new cylinder head gasket on the cylinder block
faCing its identification mark upward.
·J.D.
MARK
CYliNDER HEAD GASKET