Jeep UNIVERSAL CJ-2A - Page 38

'Jeep' UNIVERSAL and 'Jeep' DISPATCHER
D
D-41. Crankshaft Main Bearings
The crankshaft rotates on three main bearings
with a running clearance of .0003" to .0029"
[.0008
a .0074 tnm.]. These bearings are positioned
and prevented from rotating in their supports in
the cylinder block by dowel pins. Dowel pins are
used in both the center and the rear bearing caps.
No dowel pins are used in the front bearing cap be-
cause the bearing has a flange. The front main bear-
ing takes the end thrust of the crankshaft. The
main bearings are of premium type which provides
long bearing life. They are replaceable and when
correctly installed, provide proper clearance with-
out filing, boring, scraping, or shimming. Crank-
shaft bearings can be removed from this engine only
with the engine out of the vehicle. Crankshaft bear-
ings must be replaced as a complete set of three
bearings, each bearing consisting of two halves.
Main bearings are available in the standard size
and the following undersizes:
.001" [0,025 mm.] .012" [0,304 mm.]
.002" [0,050 mm.] .020" [0,508 mm.]
.010" [0,254 mm.] .030" [0,762 mm.]
The .001" and .002" undersize main bearings are
for use with standard size crankshafts having
slightly worn journals. The .010", .020", and .030"
undersize bearings are for use with undersize
crankshafts in those sizes. The .012" undersize
bearings are for use with .010" undersize crank-
shafts having slightly worn journals. Bearing sizes
are rubber stamped on the reverse side of each
bearing half.
D-42. Crankshaft Main Bearing Inspection
The crankshaft journals must be carefully inspected
as detailed previously in Par. D-38. Worn journals
will require undersize bearings. Scored, flaked, or
worn bearings must be replaced. Measure the main
bearing bores in the cylinder block using a telescope
gauge and micrometer. Measure the bores at right
angles to the split line and at 45° to the split line.
The bores should not be over .001" [0,025 mm.]
out-of-round or .001" in taper from end to end.
Also, the bores should not be more then .001"
oversize, considering the average diameter of the
bore.
D-43. Fitting Crankshaft Main Bearings
Fit the crankshaft main bearings using either
"Plastigage" or shim stock. Refer to the instruc-
tions in Section E for "Plastigage" (Par. E-46)
or shim stock (Par. E-47).
I
D-44. Connecting Rod Bearings
The connecting rod bearings, like the crankshaft
main bearings, are of the replaceable type. When
correctly installed, the bearings provide proper
clearance without filing, boring, scraping, or
shimming.
Main bearings with .maximum wearing surfaces
are obtained through the use of offset connecting
rods. When the rods are installed, the offset "A"
in Fig. 44 is placed away from the nearest main
bearing "B".
The oil spray hole should be on the "follow" side
or. away from the camshaft, toward the right side
of the vehicle. Because of the offset._ and oil spray
hole, No. 1 and 2 or No. 3 and 4 connecting rods
cannot be interchanged for if they··'are reversed,
the oil spray hole will be on the wrong side. No. 1
and 3 or No. 2 and 4 can be interchanged.
FIG. 44---CONNECTING ROD OFFSET
Connecting rod bearings sh::mld be replaced as a
complete set. Each bearing consists of two halves.
Connecting rod bearing sets are available in stand-
ard size and the following undersize:
.001" [0,025 mm.] .012" [0,304 mm.]
.002" [0,050 mm.] .020" [0,508 mm.]
.010" [0,254 mm.] .030" [0,762 mm.]
The .001" and .002" undersize bearings are for use
with standard size crankshafts having slightly
worn crankpins that do not require grindinf;!;. The
.012" undersize bearings are for use with slightly
worn crankshafts that have been previously ground
for .010" undersize bearings.
Should it be necessary to replace the bearings due
to wear, replacement of piston rings and piston
pins is also recommended.
D-45. Connecting Rod Bearing Inspection
The bearing fits may be roughly checked by shaking
the connecting rod by hand, px;iO,F 1to removal of
the bearing cap, to determine ifit is loose on the
crankshaft. The crankpins must be carefully in-
spected as detailed previously in Par. D-38. Worn
crankpins will require undersize bearings. Scored,
ijaked, or worn bearings must be replaced.
D-46. Installing Connecting Rod Bearings
New bearings must be installed so that the oil
spray. hole in the upper bearing half aligns with
the oil spray hole in the connecting rod. Each
bearing cap must be installed to seat evenly on the
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