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2. Valve lifter
a. Check each valve lifte r for scratches or other
damage. I f the lifter i s damaged
the cylinder head surface
probably also damaged. I f the damage is severe,
may be necessary
it
and the cylinder head.
NOTE: For proper valve lifter-to-head clear-
ance, always install lifters on their original
valves.
E. Camshafts, Cam Chain and Cam Sprockets
1. Camshaft
The cam lobe metal surface may have a blue
a.
discoloration due t o excessive friction. The
metal surface could also
become pitted.
NOTE: The exhaust cam appears darker than
the intake cam. This is due
ening process and is not due to excessive
heat.
enaine
b. I f any of the above wear conditions are readily
visible, the camshaft should be replaced.
c.
though the cam lobe surface appears t o
Even
be in satisfactory condition, the lobes should
be measured with a micrometer. Cam lobe
wear can occur without scarring the surface.
I f this wear exceeds a pre-determined amount,
valve timing and lift
camshaft if wear exceeds the limits.
d. Install the camshaft on the cylinder head.
Place a strip of Plastigauge between camshaft
and camshaft cap as illustrated (lengthwise
along camshaft). Tighten the nuts with
specified torque. Remove the camshaft cap
and determine the clearance by measuring
the width of the flattened Plastigauge.
any way,
in
which
rides is
in
it
replace both the lifter
to
t o flake off or
start
a special hard-
to
affected. Replace the
are
I
CYLINDER HEAD STUDS
FOR CAMSHAFT CAP
Cap Nut Tightening Torque:
0.8~1.0 m-kg (5.8~7.2 ft-lbs)
NOTE: Do not turn camshaft when measuring
clearance with Plastigauge.
Camshaft-to-cap Clearance:
Standard: .020~.054mm (.0008~.0021")
Maximum: 0.160mm (.006")
If camshaft-to-cap clearance exceeds specifica-
tion, measure camshaft bearing surface diam-
eter.
Bearing Surface Diameter:
Standard:24.97~24.98mm (0.9830~0.9835")
1) I f camshaft diameter is less than specifica-
tion, causing excessive clearance, replace
camshaft.
2) If camshaft is within specification and cam-
shaft-to-cap clearance is excessive, replace
cylinder head.
2. Cam Chain
Except in cases of oil starvation, the cam chain
wears very little. If the cam chain has stretched
excessively and it is difficult t o keep the pro-
per cam chain tension, the chain should be
replaced.
3.
Cam Sprockets
Check cam sprockets for obvious wear. Ex-
amine damping rubber on sides of cam
sprockets. If the damping rubber is disintegrat-
ing, the sprocket should be replaced. Damaged
PLASTIGAUGE
CAMSHAFT
I
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