Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 564

6A – 94 ENGINE MECHANICAL

CRANKSHAFT AND BEARING

Inspect the surface of the crankshaft journals and
crankpins for excessive wear and damage.
Inspect the oil seal fitting surfaces for excessive wear and
damage.
Inspect the oil ports for obstructions.
Note:
To increase crankshaft strength, tufftriding (Nitrizing
Treatment) has been applied. Because of this, it is not
possible to regrind the crankshaft surfaces.
Therefore, under size bearing are not available.

Crankshaft Tufftriding Inspection

1. Use an organic cleaner to thoroughly clean the

crankshaft. There must be no traces of oil on the
surfaces to be inspected.

2. Prepare a 5 – 10% solution of ammonium cuprous

chloride (dissolved in distilled water).

3. Use a syringe to apply the solution to the surface to be

inspected.
Hold the surface to be inspected perfectly horizontal to
prevent the solution from running.

Note:
Do not allow the solution to come in contact with the
oil ports and their surrounding area.

Judgment

1. Wait for thirty to forty seconds.

If there is no discoloration after thirty or forty seconds,
the crankshaft is usable.
If discoloration appears (the surface being tested will
become the color of copper), the crankshaft must be
replaced.

2. Steam clean the crankshaft surface immediately after

completing the test.

Note:
The ammonium cuprous chloride solution is highly
corrosive. Because of this, it is imperative that the
surfaces being tested be cleaned immediately after
completing the test.

ENGINE MECHANICAL 6A – 95

Crankshaft Run-Out

1. Set a dial indicator to the center of the crankshaft

journal.

2. Gently turn the crankshaft in the normal direction of

rotation.
Read the dial indicator as you turn the crankshaft.
If the measured value exceeds the specified limit, the
crankshaft must be replaced.

Crankshaft Run-Out

mm (in)

Standard Limit

0.05 (0.002) or less

0.08 (0.003)

Bearing Spread

Use a vernier caliper to measure the bearing spread.
If the measured value is less than the specified limit, the
bearing must be replaced.
Bearing Spread

mm (in)

Limit

4JA1, 4JA1T,

4JA1TC

64.5 (2.54)

Crankshaft Bearing

4JB1T, 4JG2T,

4JH1TC

74.5 (2.93)

Connecting Rod Bearing

56.5 (2.22)

6A – 96 ENGINE MECHANICAL

Crankshaft Journal and Crankpin Diameter

1. Use a micrometer to measure the crankshaft journal

diameter across points

Q

-

Q

and

R

-

R

.

2. Use the micrometer to measure the crankshaft journal

diameter at the two points (

S

and

T

).

3. Repeat

Steps

Q

and

R

to measure the crankpin

diameter.
If the measured values are less than the specified
limit, the crankshaft must be replaced.

Crankshaft Journal Diameter

mm (in)

Standard Limit

4JA1T,

4JA1,

4JA1TC

59.92 – 59.93

(2.3591 – 2.3594)

59.91 (2.3586)

4JG2T, 4JB1T,

4JH1TC

69.92 – 69.93

(2.7527 – 2.7531)

69.91 (2.7524)

Crankpin Diameter

mm (in)

Standard Limit

52.92 – 52.93

(2.0833 – 2.0839)

52.90 (2.083)

Crankshaft Journal and Crankpin
Uneven Wear

mm (in)

Standard Limit

0.05 (0.002) or less

0.08 (0.003)

Crankshaft Journal and Bearing Clearance

If the clearance between the measured bearing inside
diameter and the crankshaft journal diameter exceeds the
specified limit, the bearing and/or the crankshaft must be
replaced.
Crankshaft Journal and Bearing Clearance

mm (in)

Standard Limit

0.031 – 0.064

(0.0012 – 0.0025)

0.110 (0.0043)

Connecting Rod Bearing Inside Diameter

1. Install the bearing to the connecting rod big end.
2. Tighten the bearing cap to the specified torque.
Connecting Rod Bearing Cap Bolt
Torque kg·m

(lb.ft/N·m)

4JA1 / 4JA1T engine

8.5

± 0.5(61.4 ± 3.6 / 83.3 ± 4.9)

1st step ; 3.0

± 0.5(21.7 ± 3.6 /

29

± 5)

4JB1T / 4JG2T /
4JA1TC / 4JH1TC
engine

2nd step ; 45

° ~ 75°

ENGINE MECHANICAL 6A – 97

3. Use an inside dial indicator to measure the connecting
rod bearing inside diameter.

Crankpin and Bearing Clearance

If the clearance between the measured bearing inside
diameter and the crankpin exceeds the specified limit, the
bearing and/or the crankshaft must be replaced.
Crankpin and Bearing Clearance

mm (in)

Standard Limit

0.029 – 0.066

(0.0011 – 0.0026)

0.100 (0.0039)

Clearance Measurements (With Plastigage)

Crankshaft Journal and Bearing Clearance

1. Clean the cylinder body, the journal bearing fitting

surface, the bearing caps, and the bearings.

2. Install the bearings to the cylinder body.
3. Carefully place the crankshaft on the bearings.
4. Rotate the crankshaft approximately 30

° to seat the

bearing.

5. Place the Plastigage (arrow) over the crankshaft

journal across the full width of the bearing.

6. Install the bearing caps with the bearing.

7. Tighten the bearing caps to the specified torque.
Crankshaft Bearing Cap Bolt Torque

kg·m (lb.ft/N·m)

17

± 1 (123.0 ± 7.2/166.7 ± 9.8)

Do not allow the crankshaft to turn during bearing cap
installation and tightening.
8. Remove the bearing cap.