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tight when the cap is drawn down. Draw
each cap down with 180 to 190 foot pounds
pull on a torque wrench. Drawing the caps
any tighter will distort the bearings.
4. A recommended method of determining the
running clearance between the bearings and
journals is to insert a 1/32" diameter soft
lead wire or foil across the center of each
lower bearing shell by removing and replac-
ing one bearing cap at a time. When the
lead wire or foil insertions have been made,
E FREE DIA.
C
=
/-r" APPROX.
"An IS .001" SMALLER THAN "8"
"e"
IS
.0005" THICKER THAN "D"
"E" IS .030'" GREATER THAN "F"
fig. 31 - Inside Diameter Of Bearing Shells
tighten the bearing cap bolts, to 180 to 190
foot pounds torque, thus "squeezing" the wire
or foil to shim thickness between the shells
and the crank 'journals. Remove the lead
shims and measure them for thickness; the
clearance between the shells and the journals
should be from .002" to .006."
5. Check the end thrust of the crankshaft, which
is taken on rear main bearing. The minimum
end play should be .004" to .011" and
should not exceed .018"; replace the thrust
washers if the play exceeds .018".
D. Main Bearing Replacement.
The main bearings may be replaced with the engine
in the tractor as explained in "REPLACEMENT OF
CRANKSHAFT MAIN BEARINGS" in this section.
However, it is not advisable or recommended that
the work be done in that manner except in emer-
gency cases. Installation of the bearings with the
engine disassembled is described in "ASSEMBLY
OF ENGINE" in this section.
E. Replacement of Crankshaft Oil Seals.
Drive or press the oil seals from the flywheel hous-
109
ing and the timing gear cover and install new ones
each time that the engine is disassembled. Use a
flat piece of metal to press the new seals into place
to prevent damaging the seal. The lip side of each
seal should be toward the inner side of the housing
and the cover. The lips must face each other when
the housing and the cover are installed on the en-
gine.
Effective on Engine Serial Number 2A-2129, the
crankshaft incorporates an oil slinger to improve
the oil sealing at the rear end of the crankshaft.
This oil slinger can be made adaptable to engines
prior to 2A-2129 by machining the flywheel hous-
ing opening, for !he crankshaft, to
5Y,"
diameter
to provide clearance for the oil slinger. To facili-
tate installation, heat the slinger in oil approxi-
mately 250
0
F., then install it on the crankshaft so
that the tapered side of the oil slinger is toward
the rear of the crankshaft and is located 1-3/32"
from the end face of the crankshaft.
NOTE: When the engine is being rebuilt it is rec-
ommended that the flywheel housing be reworked
and the oil slinger be installed, particularly if
excessive oil leakage at this point has been ex-
perienced.
F. Replacement of Pilot Bearing Oil Wick.
Turn the wick holder out of the crankshaft, then
pull the wick out of the crankshaft. Since the out-
side diameter of the wick is approximately 5/64"
larger than the inside diameter of the wick holder,
difficulty has been experienced in the field when
assembling the wick in the holder. Therefore, the
complete assembly is recommended for replace-
ment. The new wick assembly should be soaked
in engine oil for 24 hours before it is assembled.
1. Coat the threads of the wick holder with
"Permatex" or its equivalent, then insert the
wick into the crankshaft and tighten the
holder securely.
It is important that the wick fits tightly in the
hole in the crankshaft and also in the holder.
Use a small punch and hammer to pack the
wick tightly in the hole.
2. The flywheel end of the wick should extend
out 5/8" from the rear face of the crank-
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