Cylinder Head/Valves - Westerbeke W70GA Service Manual

CYLINDER HEAD
I
VALVES
INSPECTION
I
REPAIR
INSPECTION
Clean off the cylinder head and remove any
gasket fragments.
Inspect for damage, cracks, and leakage of water or oil.
FEELER GAUGE
Measure the cylinder head distortion in the six directions
shown below using a gauge and straight edge.
Distortion: 0.15mm (0.0016 in)
If the cylinder head distortion exceeds specification, grind the
cylinder head surface.
If the cylinder head height is not within specification,
replace it.
HEIGHT: 91.95-92.05mm (3.62D-3.624in)
GRINDING LIMIT: 0.20mm (0.008in ) MAX
NOTE:
Before grinding the cylinder head, first check the \
following. Replace if necessary.
• Sinking of valve seat
• Damage of manifold contact suiface
• Camshaft oil clearance and end play.
MANIFOLD MOUNTING SURFACE
Use the same inspection procedure for the manifold
mounting surface, measuring distortion with a gauge and a
straightedge in several directions.
DISTORTION (GRINDING LIMIT): 0.20mm (0.008in)
VALVE AND VALVE GUIDE
1. Inspect each valve for the following. Replace or
resurface if necessary.
(1)
Damage or bent stem
(2) Roughness or damage to face
(3) Damage or uneven wear of stem tip
2. Check the valve head margin thickness. Replace
if necessary.
VALVE HEAD MARGIN THICKNESS
IN: 0.5 mm (0.020in) MIN.
EX: 1.0mm (0.039in) MIN.
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3. Measure the valve stem diameter.
DIAMETER (STANDARD)
IN: 8.03D-8.045mm (0.3161-0.3167in)
EX: 8.025-8.040mm (0.3159-0.3165in)
LIMIT
IN: 7.98Dmm
EX: 7.975mm
MEASURING VALVE ·
STEM DIAMETER
VALVE GUIDE l.D.
IN: B.07-8.09mm (0.3177-D.3185in)
EX: 8.07-8.09mm (0.3177·D.3185in)
Engines & Generators
15