Isuzu N-Series. Manual - part 585

6A1-28 4JB1/4JB1-TC/4JG2/4JH1-TC - ENGINE

7. Timing Gear Case Cover

1) Align the gear case with the timing gear case

knock pin and then install the timing gear case
cover.

2) Tighten the gear case cover bolts to the speci-

fied torque.

8. Noise Cover Spacer
9. Noise Shield Cover

10. Crankshaft Damper Pulley

Tighten the crankshaft damper pulley bolt to the
specified torque.

Notice:
Hold the flywheel ring gear stationary to prevent the
crankshaft from turning when tightening the damper pul-
ley.

Tighten:

• Pulley boss bolt to 206 N

⋅m (21 kg⋅m / 152 lb⋅ft)

11. Cooling Fan Assembly

• Mount fan pulley, distance piece, and cooling fan

assembly (in this order) on the water pump, and
tighten to the specified torque.

Tighten:

• 8  N

⋅m (0.8 kg⋅m / 69 lb⋅in)

12. AC Generator Drive Belt

• Install AC Generator drive belt and adjust belt ten-

sion.

• Depress the drive belt mid-portion with a 98 N (10

kg / 22 lb) force.

• Tighten the idler lock nut to the specified torque.

Tighten:

• Idler lock nut to 27 N

⋅m (2.8 kg⋅m / 20 lb⋅ft)

13. Power Steering Pump Drive Belt (P/S Model)

• Install Power Steering pump drive belt and adjust

belt tension.

• Depress the drive belt mid-portion with a 98 N (10

kg / 22 lb) force.

• Tighten the idler lock nut to the specified torque.

Tighten:

• 27  N

⋅m (2.8 kg⋅m / 20 lb⋅ft)

14. Fan shroud

• Install the fan shroud and reservoir tank hose.
• Pour coolant
• Start the engine and check coolant leakage.

N6A3169E

N6A3170E

Drive Belt Deflection

mm (in)

8 (0.31) — 12 (0.47)

Drive Belt Deflection

mm (in)

8 (0.31) — 12 (0.47)

4JB1/4JB1-TC/4JG2/4JH1-TC - ENGINE 6A1-29

IDLE GEAR “B” (4JH1-TC SCISSOR GEAR)

Component

Reassembly

1. Drive pins into the main gear, the front gear, and

the rear gear.

2. Apply pressure to the main gear bearing from the

front side of the main gear (the side with the
groove).

3. Place the special tool in a vise so that the main

gear is pushed up toward the rear side.
Scissor gear setting tool
Base: 5-86739-149-0

Legend

1. Snap ring

6. Spring

2. Rear gear

7. Front gear

3. Spring

8. Snap ring

4. Main gear

9. Lock bolt

5. Bearing

N6A3275E

N6A3276E

N6A3277E

6A1-30 4JB1/4JB1-TC/4JG2/4JH1-TC - ENGINE

4. Set the spring as shown in the illustration.

5. Position the rear gear so that it pin is aligned with

the receiving end of the spring.

6. Install the snap ring to the main gear groove.

7. Set the rear gear setting hole to the pin of the spe-

cial tool.

N6A3278E

N6A3279E

N6A3280E

N6A3281E

4JB1/4JB1-TC/4JG2/4JH1-TC - ENGINE 6A1-31

8. Place the special tool in a vise so that the main

gear is pushed up toward the front side.

9. Repeat Steps 3, 4, and 5.

10. Use the special tool to mesh the teeth of the front

gear, the main gear, and the rear gear.

11. Insert a lock bolt (M6 

× 1.00 L = 30) (1) into the

scissor gear fixing hole to prevent the scissor gear
from turning.
Scissor gear setting tool
Lever: 5-86739-150-0

N6A3282E

N6A3283E

N6A3284E