Jeep UNIVERSAL CJ-2A - Page 39

D
L4-134 ENGINE
connecting rod from which it was removed, and in
the same position. After wiping and carefully in-
specting the bearing bore in the connecting rod,
install the proper bearing. Never file either the
bearing cap or the bearing to compensate for too
much clearance. Do not use shims under a bearing
cap or behind a bearing shell. Do not run a new
bearing half with a worn half.
The desired running fit (difference betweea the
diameter of the crankpin and the inside diameter
of the fitted bearing) for a connecting rod bearing
is .001" to .0019" [0,025 a 0,048 mm.]. With a
dimension in excess of this standard running fit, a
satisfactory bearing replacement cannot be made
and it will be necessary to regrind the crankshaft.
Install the bearing lower half and the connecting
rod cap and draw the cap bolt nuts down equally
and only slightly tight. Move the connecting rod
endwise, one way or the other, on the crankshaft
to be sure the bearing is not tight. Pull the nuts
tighter, first one then the other, a little at a time,
and keep trying the fit of the rod on the crankshaft
by hand until the recommended torque of 35
to 45 lb-ft. [4,8 a 6,2 kg-m.] is reached. If the
bearings are of the correct size, and have been
properly lubricated with light engine oil before in-
stallation, the connecting rod should be easy to
slide back and forth parallel to the crankpin.
If the connecting rod is tight on the crankshaft, a
larger bearing is required. If there is no binding
or tightness, it is still necessary to check clearance
to guard against too loose a fit. The use of "Plasti-
gage" or shim stock of the proper size to measure
.0010" to .0019" [0,025 a 0,0483 mm.] clearance is
recommended for checking connecting rod bearing
clearances. This is the same material recommended
for checking crankshaft main bearings and the
method of checking is similar. Refer to Par. E-46
or E-4 7. Connecting rod bearings are fitted to the
same clearance as the main bearings but the torque
specified for connecting rod cap bolts is different.
NOTE: Should it be necessary to replace a scored
or burned No. 1 connecting rod bearing, see Par.
D-84 regarding timing gear oil jet.
D-47. Connecting Rod Side Play
Check the connecting rod side play with a feeler
gauge as shown in Fig. 45. The side clearance is
.004" to .010" [0.1016 a 0,254 mm.].
D-48. o.mshaft and Bearings
The camshaft is supported at four points in the
cylinder block. The front is supported in a re-
placeable, steel-shell, babbit-lined bearing. The
bearing is pressed into place. The other three bear-
ing surfaces are precision machined in the cylinder
block. The camshaft bearings are pressure lubri-
cated through drilled passages in the crankcase.
End thrust of the camshaft is taken by a thrust
plate bolted to the crankcase. The camshaft is
driven by a silent helical-cut tooth timing gear at
the front of the engine. A worm gear, integral with
the camshaft, drives the oil pump and distributor.
38
FIG. 45-CONNECTING ROD SIDE PLAY
The fuel pump is actuated by an eccentric forged
onto the camshaft.
Clean the camshaft thoroughly in cleaning solvent.
Inspect all camshaft bearing surfaces to determine
if they are scored or rough. The cam faces must be
perfectly smooth throughout their contact face
and must not be scored or worn.
D-49. Camshaft Front Bearing Replacement
Use a suitable driver to remove the camshaft front
bearing from the cylinder block. To install a new
bearing, align the oil hole in the bearing with the
bored oil hole in the cylinder block and drive the
bearing in until the front end of the bearing is
flush with the front surface of the cylinder block.
Make sure the oil hole is open and clear. It is not
necessary to line-ream the bearing after installation
because bearings for replacement are precision
reamed to the finished size.
D-50. ·Camshaft End Play
End play of the camshaft is determined by running
clearance between the rear face of the camshaft
gear and the thrust plate and is established by the
spacer thickness. The standard clearance is .004"
to .007" [0,102 a 0,178 mm.] and can be measured
by a dial indicator. As a general rule this clearance
will change but little through wear or when a new
gear is installed. To predetermine the correct end
float with the gear, spacer, and thrust plate re-
moved, measure the thickness of both the thrust
plate and spacer with a micrometer. The thickness
of the spacer should be approximately .006"
[0,152 mm.] greater than that of the thrust plate.
When this is correct and the parts are assembled
and drawn tightly together by the gear retaining
screw, the end play should come within standard
limits.