Isuzu N-Series. Manual - part 568

GENERAL ENGINE MECHANICAL 6A-29

2. Stiffener & Space Rubber

• Remove the stiffener from of the oil pan left &

right side.

• Take out space rubber.

3. Oil Pan Assembly
4. Oil Pump Assembly

Installation

1. Oil Pump Assembly

• Apply molybdenum mixed engine oil to drive

gear of camshaft and driven gear of oil pump.

• Tighten the oil pump fixing bolt to the specified

torque.

Tighten:
19 N

⋅m (1.9 kg⋅m/14 lb⋅ft)

2. Oil Pan Assembly

• Apply the recommended liquid gasket or its

equivalent to the No. 5 bearing cap arches, the
grooves, the cylinder block and the timing gear
case fitting face at the positions shown in the il-
lustration.

• Fit the gasket rear lipped portion into the No. 5

groove.

• Be absolutely sure that the lipped portion is fit-

ted snugly into the groove.

• Install the oil pan to the cylinder body.
• Tighten the oil pan bolts to the specified torque.

Tighten:
Oil Pan Bolt to 19 N

⋅m (1.9 kg⋅m/14 lb⋅ft)

3. Stiffener & Space Rubber

• Install the space rubber.
• Install the stiffener tighten to the specified

torque.

Tighten:

• Engine Body Side to 37 N

⋅m (3.8 kg⋅m/27 lb⋅ft)

• Clutch Housing Side to 78 N

⋅m (8.0 kg⋅m/58 lb⋅ft)

4. Vacuum Pump Oil Hose

• Install the oil hose to oil pan.

N6A3125E

N6A3126E

6A-30 GENERAL ENGINE MECHANICAL

CRANKSHAFT

Component

Disassembly

1. Cylinder Head Assembly and Gasket
2. Oil Pan Ambly
3. Timing Gear (Gear Drive Model)
4. Timing Belt and Pulley (Belt Drive Model)

5. Front Oil Seal

• With the oil seal pushed in deep, install the spe-

cial tool as shown in the illustration to remove
the oil seal.
Remover: 5-8840-2362-0

Legend

1. Cylinder head assembly and gasket

9. Piston cooling oil pipe

2. Oil pan assembly

10. Piston and connecting rod

3. Timing gear

11. Flywheel

4. Timing belt and pulley

12. Cylinder block rear plate

5. Front oil seal

13. Crankshaft rear oil seal

6. Timing gear housing

14. Main bearing cap

7. Timing pulley housing

15. Crankshaft

8. Oil pump assembly

N6A3127E

GENERAL ENGINE MECHANICAL 6A-31

6. Timing Gear Housing
7. Timing Pulley Housing
8. Oil Pump Assembly
9. Piston Cooling Oil Pipe

10. Piston and Connecting Rod
11. Flywheel
12. Cylinder Block Rear Plate
13. Crankshaft Rear Oil Seal (Gear and Belt Drive

Model)

• With the oil seal pushed in deep, install the spe-

cial tool as shown in the illustration to remove
the oil seal.
Remover: Rear Oil Seal 5-8840-2360-0

Notice:
Take care not to damage sealing surface of rear plate
and crankshaft when removing oil seal.

14. Main Bearing Cap
15. Crankshaft

Inspection and Repair

Make the necessary adjustments, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.

1. Crankshaft

Thrust clearance
Set the dial indicator as shown in the illustration
and measure the crankshaft thrust clearance.
If the thrust clearance exceeds the specified limit,
replace the thrust bearing as a set.

2. Main bearing clearance

1) Remove the main bearing caps in the se-

quence shown in the illustration.
Arrange the removed main bearing caps in the
cylinder number order.

N6A3128E

N6A3129E

Thrust clearance

mm (in)

Standard

Limit

0.10 (0.0039)

0.30 (0.0118)

N6A3130E

N6A3131E

6A-32 GENERAL ENGINE MECHANICAL

2) Remove the crankshaft. Remove the main

bearings.

3) Clean the upper and lower bearings as well as

the crankshaft main journal.

4) Check the bearings for damage or excessive

wear.
The bearings must be replace as a set if dam-
age or excessive wear is discovered during in-
spection.

5) Set the upper bearings and the thrust washers

to their original positions. Carefully install the
crankshaft.

6) Set the lower bearings to the bearing cap origi-

nal position.

7) Apply plastigage to the crankshaft journal unit

as shown in the illustration.

8) Install the main bearing caps. Apply engine oil

to the bolt threads and the seats. Tighten the
bolts to the specified torque.

Tighten:
167 N

⋅m (17 kg⋅m/123 lb⋅ft)

Notice:
Do not allow the crankshaft to rotate.

9) Remove the main bearing caps.
10) Measure the plastigage width and determine

the oil clearance. If the oil clearance exceeds
the specified limit, replace the main bearings as
a set and/or replace the crankshaft.

11) Clean the plastigage from the bearings and the

crankshaft.

12) Remove the crankshaft and the bearings.

3. Run-out

1) Carefully set the crankshaft on the V-blocks.

Slowly rotate the crankshaft and measure the
runout.
If the crankshaft runout exceeds the specified
limit, the crankshaft must be replaced.

N6A3132E

Oil Clearance

mm (in)

Standard

Limit

4JB1
4JB1-TC

0.035 — 0.080 

(0.0014 — 0.0036)

0.11 (0.0043)

4JG2

0.031 — 0.063 

(0.0012 — 0.0025)

4JH1-TC

0.037 — 0.068 

(0.0015 — 0.0027)

Run-Out

mm (in)

Standard

Limit

0.05 (0.0020) or less

0.08 (0.0031)

N6A3133E