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PISTON TO CYLINDER
SPLIT-SKIRT
CAM-GROUND
AT PISTON SKIRT
.004 to .005"
.0037 to .0042"
PISTON RING GAP
,010 to ,020"
TOP RING
.0015 to .0035"
PISTON RING
SIDE
CLEARANCE
tN
GROOVES
2nd, 3rd RING
.0015 to .0035"
OIL RING
.002 to .004"
PISTON PIN TO
.0005 to .0011"
CONNECTING ROD BUSHING
.0000 to .0008"
PISTON PIN TO PISTON
tight
CONNECTING ROD TO
.009 to .016"
CRANK PIN - SIDE
CLEARANCE
CONNECTING ROD SHELL BEARING
.0013 to .0035"
TO CRANK PIN DIA.
(VERTICAL)
CONNECTING ROD BABBITT
.0015 to .0028"
BEARING TO CRANK PIN
,
.
2.126 DIA GRIND
:
__
~
2.125
'
STANDARD CRANK PIN DIMENSIONS
Fig. 34,
PISTON,
RING AND ROD CLEARANCES CHART
LIFTER
RETAINER LOCKS
Fig. 35
The cylinder
blocks do not have to be removed unless
the cylinder bore is scored, outoof-round, or worn over-
size more than 0.005 inch. In this
event,
the block
will have to be removed, rebored and fitted
with over-
size pistons and rings. In reasserably, use new gaskets and
tighten cylinder block mounting nuts to 56-62 foot pounds
torque.
VALVES and SEAT INSERTS (Fig.
35)
Remove tappet inspection cover and compress valve
springs with a standard automotive valve lifter. Wedge
a rag into the opening at the bottom of valve chamber
so the retaining locks do not fall into crankcase. Re-
move retaining locks, seats, springs, valves and
clean these, as well as the ports and guides, of all
carbon and gum deposits. Tag each valve so that they
can be put back into the same guides they were re-
moved from. Replace valves that are burned or pitted.
The exhaust valves are furnished
with positive
type
rotators.
The valve
rotates
slightly
each time it
opens, and thereby prevents
the build
up of foreign
deposits
on the valve face and stem. Clean and in-
spect operation of rotator
- replace if necessary.
The inlet
and exhaust valve seat inserts
can be
moved, when replacement
becomes
necessary,
by
means of Wisconsin Motor DF-68oA insert
puller.
Before 9finding valves,
inspect
valve guides for pos-
sible
replacement.
Refer to la/,r
Cuidc paragraph.
The valve face is ground at 45 ° to the vertical
center
line of the valve stem and the valve seat insert should
also be ground at a 45 ° angle.
After 9finding,
lap
valves inplace until
a uniform ring will show entirely
around the face of the valve.
Clean valves and wash
block thoroughly
with a hot solution
of soap and
water. Wipe cylinder
walls with clean lint
free rags
and light engine oil.
Valve 9uides
in the cylinder
block are easily
re-
placeable
by use of Wisconsin DF-72 driver tool.
The
valve stem has a clearance
of .003 to .005" in the
guide.
When the clearance
becomes .007",
the guides
should be driven out and replaced.
CRANKSHAFT (Fig.
36)
Remove main bearing
plate
at take~off
end.
The
crankshaft
can then be taken out from that
end of
crankcase.
In reossembly,
use same thickness
of
gaskets
and shims to establish
the correct
end
play for the tapered
main roller
bearings.
Fig. 36
23
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Troubleshooting
