Dodge dakota 2002 Service Manual page 1292

DR
CRANKSHAFT MAIN
BEARINGS
STANDARD PROCEDURE
MAIN BEARING FITTING
SELECT FIT IDENTIFICATION
The main bearings are "select fit" to achieve proper
oil clearances. For main bearing selection, the crank-
shaft position sensor target wheel has grade identifi-
cation marks stamped into it (Fig. 36). These marks
are read from left to right, corresponding with jour-
nal number 1, 2, 3, 4. The crankshaft position sensor
target wheel is mounted to the number 6 counter
weight on the crankshaft.
Fig. 36 MARKINGS ON TARGET WHEEL
1 - REARMOST CRANKSHAFT COUNTER WEIGHT
2 - TARGET WHEEL
3 - MAIN BEARING SELECT FIT MARKINGS
INSPECTION
Wipe the inserts clean and inspect for abnormal
wear patterns and for metal or other foreign material
imbedded in the lining. Normal main bearing insert
wear patterns are illustrated.
Inspect the back of the inserts for fractures, scrap-
ings or irregular wear patterns.
Inspect the upper insert locking tabs for damage.
Replace all damaged or worn bearing inserts.
MAIN BEARING JOURNAL DIAMETER
(CRANKSHAFT REMOVED)
Remove the crankshaft from the cylinder block(Re-
fer to 9 - ENGINE/ENGINE BLOCK/CRANKSHAFT
- REMOVAL).
Clean the oil off the main bearing journal.
Determine the maximum diameter of the journal
with a micrometer. Measure at two locations 90°
apart at each end of the journal.
The maximum allowable taper is 0.008mm (0.0004
inch.) and maximum out of round is 0.005mm (0.002
inch). Compare the measured diameter with the jour-
nal diameter specification (Main Bearing Fitting
Chart). Select inserts required to obtain the specified
bearing-to-journal clearance.
Install the crankshaft into the cylinder block(Refer
to 9 - ENGINE/ENGINE BLOCK/CRANKSHAFT -
INSPECTION).
Check crankshaft end play.
CRANKSHAFT MAIN BEARING SELECTION
(1) Service main bearings are available in four
grades. The chart below identifies the four service
grades available.
Crankshaft
MARKING
R Size 63.488 - 63.496 mm
(2.4995 - 2.4998 in.)
S Size 63.496 - 63.500 mm (2.4998 - 2.4999
in.)
T Size 63.500 - 63.504 mm (2.4999 - 2.501
in.)
U Size 63.504 - 63.512 mm (2.5001 - 2.5004
in.)
Bearing size
Bearing Size
Code
Upper Bearing
A .2.443 - 2.447
mm
(.0961 - .0963
in.)
B 2.439 - 2.443
mm
(0.960 -.o961
in.)
C 2.435 - 2.439
mm
ENGINE - 3.7L 9 - 43
JOURNAL SIZE
SIZE mm (in.)
Application
Use with crankshaft
size R
Use with crankshaft
S, T
Use with crankshaft
U