Dodge Dakota (R1). Manual - part 462

STANDARD PROCEDURE—CRANKSHAFT MAIN
BEARINGS - FITTING

CRANKSHAFT INSTALLED

The main bearing caps, numbered (front to rear)

from 1 through 5 have an arrow to indicate the for-
ward position. The upper main bearing inserts are
grooved to provide oil channels while the lower
inserts are smooth.

Each bearing insert pair is selectively fitted to its

respective journal to obtain the specified operating
clearance. In production, the select fit is obtained by
using various-sized color-coded bearing insert pairs
as listed in the Main Bearing Fitting Chart. The
bearing color code appears on the edge of the insert.
The size is not stamped on bearing inserts used
for engine production.

The main bearing journal size (diameter) is identi-

fied by a color-coded paint mark on the adjacent
cheek or counterweight towards the rear of the
crankshaft (flange end). The rear main journal, is
identified by a color-coded paint mark on the crank-
shaft rear flange.

When required, upper and lower bearing inserts of

different sizes may be used as a pair. A standard size
insert is sometimes used in combination with a 0.025
mm (0.001 inch) undersize insert to reduce the clear-
ance by 0.013 mm (0.0005 inch). Never use a pair
of bearing inserts with greater than a 0.025 mm
(0.001 inch) difference in size.

BEARING INSERT PAIR CHART

INSERT

CORRECT

INCORRECT

UPPER

STANDARD

LOWER

0.025 mm U/S

0.051 mm U/S

(0.001 in.)

(0.002 in.)

NOTE: When replacing inserts, the odd size inserts
must be either all on the top (in cylinder block) or
all on the bottom (in main bearing cap).

Once the bearings have been properly fitted, (Refer

to 9 - ENGINE/ENGINE BLOCK/CRANKSHAFT
MAIN BEARINGS - INSTALLATION).

CRANKSHAFT REMOVED

Remove the crankshaft from the cylinder block.
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 and out of round is

0.013 mm (0.0005 inch). Compare the measured
diameter with the journal diameter specification

(Main Bearing Fitting Chart). Select inserts required
to obtain the specified bearing-to-journal clearance.

Once the proper clearances have been obtained,

(Refer to 9 - ENGINE/ENGINE BLOCK/CRANK-
SHAFT MAIN BEARINGS - INSTALLATION).

MAIN BEARING FITTING CHART

Crankshaft Journals #1 - #4

Color

Diameter

Upper

Insert

Lower Insert

Code

Size

Yellow

63.5025 -

Yellow -

63.4898

Standard

(2.5001 -

2.4996

in.)

Orange

63.4898 -

Blue -

Yellow -

63.4771

Undersize

Standard

(2.4996 -

0.025 mm

2.4991

in.)

(0.001 in.)

0.0127

(0.0005

in.)

Undersize

Blue

63.4771 -

Blue -

63.4644

Undersize

(2.4991 -

0.025 mm

2.4986

in.)

(0.001 in.)

0.0254

(0.001

in.)

Undersize

Green

63.4644 -

Blue -

Green -

63.4517

Undersize

(2.4986 -

0.025 mm

0.051 mm

2.4981

in.)

(0.001 in.)

(0.002 in.)

9 - 36

ENGINE 2.5L

CRANKSHAFT MAIN BEARINGS (Continued)

Crankshaft Journals #1 - #4

0.0381

(0.0015

in.)

Undersize

Red

63.2485 -

Red -

63.2358

Undersize

(2.4901 -

0.254 mm

2.4896

in.)

(0.010 in.)

0.254

(0.010

in.)

Undersize

Crankshaft Journal #5 Only

Color

Diameter

Upper

Insert

Lower Insert

Code

Size

Yellow

63.4873 -

Yellow -

63.4746

Standard

(2.4995 -

2.4990

in.)

Orange

63.4746 -

Blue -

Yellow -

63.4619
mm

Undersize

Standard

(2.4990 -

0.025 mm

2.4985
in.)

(0.001 in.)

0.0127
mm

(0.0005
in.)

Undersize

Blue

63.4619 -

Blue -

63.4492

Undersize

(2.4985 -

0.025 mm

2.4980

in.)

(0.001 in.)

Crankshaft Journals #1 - #4

0.0254

(0.001

in.)

Undersize

Green

63.4492 -

Blue -

Green -

63.4365

Undersize

(2.4980 -

0.025 mm

0.051 mm

2.4975

in.)

(0.001 in.)

(0.002 in.)

0.0381

(0.0015

in.)

Undersize

Red

63.2333 -

Red -

63.2206

Undersize

(2.4895 -

0.254 mm

2.4890

in.)

(0.010 in.)

0.254

(0.010

in.)

MEASURING BEARING-TO-JOURNAL CLEARANCE
(CRANKSHAFT INSTALLED)

When using Plastigage, check only one bearing

clearance at a time.

Install the grooved main bearings into the cylinder

block and the non-grooved bearings into the bearing
caps.

Install the crankshaft into the upper bearings dry.
Place a strip of Plastigage across full width of the

crankshaft journal to be checked.

Install the bearing cap and tighten the bolts to 108

N·m (80 ft. lbs.) torque.

NOTE: DO NOT rotate the crankshaft. This will
cause the Plastigage to shift, resulting in an inaccu-
rate reading. Plastigage must not be permitted to
crumble. If brittle, obtain fresh stock.

Remove the bearing cap. Determine the amount of

clearance by measuring the width of the compressed
Plastigage with the scale on the Plastigage envelope

ENGINE 2.5L

9 - 37

CRANKSHAFT MAIN BEARINGS (Continued)

(Fig. 40). Refer to Engine Specifications for the
proper clearance.

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.
Install bearings (Refer to 9 - ENGINE/ENGINE
BLOCK/CRANKSHAFT

MAIN

BEARINGS

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 indicated 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.

If the clearance exceeds specification using a pair

of 0.051 mm (0.002 inch) undersize bearing inserts,
measure

crankshaft

journal

diameter

with

micrometer. If the journal diameter is correct, the
crankshaft bore in the cylinder block may be mis-
aligned, which requires cylinder block replacement or
machining to true bore.

If journals 1 through 5 diameters are less than

63.4517 mm (2.4981 inches), replace crankshaft or
grind crankshaft down to accept the appropriate
undersize bearing inserts.

Once the proper clearances have been obtained,

(Refer to 9 - ENGINE/ENGINE BLOCK/CRANK-
SHAFT MAIN BEARINGS - INSTALLATION).

REMOVAL

(1) Disconnect negative cable from battery.
(2) Remove the spark plugs.
(3) Raise the vehicle.
(4) Remove the oil pan (Refer to 9 - ENGINE/LU-

BRICATION/OIL PAN - REMOVAL) and oil pump
(Refer to 9 - ENGINE/LUBRICATION/OIL PUMP -
REMOVAL).

(5) Remove only one main bearing cap and lower

insert at a time (Fig. 41).

Fig. 40 Measuring Bearing Clearance with

Plastigage

1 - PLASTIGAGE SCALE
2 - COMPRESSED PLASTIGAGE

Fig. 41 Removing Main Bearing Caps and Lower

Inserts

1 - CONNECTING ROD JOURNAL
2 - MAIN BEARING CAPS

9 - 38

ENGINE 2.5L

CRANKSHAFT MAIN BEARINGS (Continued)

(6) Remove the lower insert from the bearing cap.
(7) Remove the upper insert by LOOSENING (DO

NOT REMOVE) all of the other bearing caps. Now
insert a small cotter pin tool in the crankshaft jour-
nal oil hole. Bend the cotter pin as illustrated to fab-
ricate the tool (Fig. 42). With the cotter pin tool in
place, rotate the crankshaft so that the upper bear-
ing insert will rotate in the direction of its locking
tab. Because there is no hole in the No.3 main jour-
nal, use a tongue depressor or similar soft-faced tool
to remove the bearing insert (Fig. 42). After moving
the insert approximately 25 mm (1 inch), it can be
removed by applying pressure under the tab.

(8) Using the same procedure described above,

remove the remaining bearing inserts one at a time
for inspection.

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 (Fig. 43).

NOTE: If any of the crankshaft journals are scored,
remove the engine for crankshaft repair.

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.

INSTALLATION

(1) Lubricate the bearing surface of each insert

with engine oil.

(2) Loosen all the main bearing caps. Install the

main bearing upper inserts.

(3) Install the lower bearing inserts into the main

bearing caps.

(4) Install the main bearing cap(s) and lower

insert(s).

(5) Clean the rear main bearing cap (No.5) mating

surfaces.

(6) Apply Mopar

t Gasket Maker, or equivalent on

the rear bearing cap (Fig. 44). The bead should be 3
mm (0.125 in) thick. DO NOT apply Mopar

t Gasket

Maker, or equivalent to the lip of the seal.

(7) Install the rear main bearing cap. DO NOT strike

the cap more than twice for proper engagement.

(8) Tighten the bolts of caps 1, 3, 4 and 5 to 54

N·m (40 ft. lbs.) torque. Now tighten these bolts to 95
N·m (70 ft. lbs.) torque. Finally, tighten these bolts to
108 N·m (80 ft. lbs.) torque.

(9) Push the crankshaft forward and backward.

Load the crankshaft front or rear and tighten cap
bolt No.2 to 54 N·m (40 ft. lbs.) torque. Then tighten
to 95 N·m (70 ft. lbs.) torque and finally tighten to
108 N·m (80 ft. lbs.) torque.

(10) Rotate the crankshaft after tightening each

main bearing cap to ensure the crankshaft rotates
freely.

(11) Check crankshaft end play. Crankshaft end

play is controlled by the thrust bearing which is
flange and installed at the No.2 main bearing posi-
tion.

Fig. 42 Removing Upper Inserts

1 - COTTER PIN
2 - FABRICATED TOOL
3 - BEARING INSERT
4 - TONGUE DEPRESSOR

Fig. 43 Main Bearing Wear Patterns

1 - UPPER INSERT
2 - NO WEAR IN THIS AREA
3 - LOW AREA IN BEARING LINING
4 - LOWER INSERT

ENGINE 2.5L

9 - 39

CRANKSHAFT MAIN BEARINGS (Continued)

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