Jeep cherokee 2000 Service Manual page 774

9 - 84 4.0L ENGINE
SERVICE PROCEDURES (Continued)
1 – NO. 7 MAIN JOURNAL SIZE PAINT MARK
2 – NO. 6 CONNECTING ROD JOURNAL SIZE PAINT MARK
BEARING INSERT PAIRS CHART
INSERT CORRECT
UPPER STANDARD
LOWER 0.025 mm
(0.001 in.)
UNDERSIZE
(Fig. 37). Refer to Engine Specifications for the
proper clearance.
Fig. 37 Measuring Bearing Clearance with
Plastigage
1 – PLASTIGAGE SCALE
2 – COMPRESSED PLASTIGAGE
Fig. 36 Crankshaft Journal Size Paint I. D. Location
INCORRECT
STANDARD
0.051 mm
(0.002 in.)
UNDERSIZE
3 – NO. 1 CONNECTING ROD JOURNAL SIZE PAINT MARK
4 – NO. 1 MAIN JOURNAL SIZE PAINT MARK
Plastigage should indicate the same clearance
across the entire width of the insert. If clearance var-
ies, it may indicate a tapered journal or foreign
material trapped behind the insert.
If the specified clearance is indicated and there are
no abnormal wear patterns, replacement of the bear-
ing inserts is not necessary. Remove the Plastigage
from the crankshaft journal and bearing insert. Pro-
ceed to Crankshaft Main Bearing—Installation.
If the clearance exceeds specification, install a pair
of 0.025 mm (0.001 inch) undersize bearing inserts
and measure the clearance as described in the previ-
ous steps.
The clearance indicate with the 0.025 mm (0.001
inch) undersize insert pair installed will determine if
this insert size or some other combination will pro-
vide the specified clearance. FOR EXAMPLE: If the
clearance was 0.0762 mm (0.003 inch) originally, a
pair of 0.0254 mm (0.001 inch) undersize inserts
would reduce the clearance by 0.0254 mm (0.001
inch). The clearance would then be 0.0508 mm (0.002
inch) and within the specification. A 0.051 mm (0.002
inch) undersize bearing insert and a 0.0254 mm
(0.001 inch) undersize insert would reduce the origi-
nal clearance an additional 0.0127 mm (0.0005 inch).
The clearance would then be 0.0381 mm (0.0015
inch).
CAUTION: Never use a pair of inserts that differ
more than one bearing size as a pair.
FOR EXAMPLE: DO NOT use a standard size
upper insert and a 0.051 mm (0.002 inch) undersize
lower insert.
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