Isuzu N-Series. Manual - part 620

6C-50 ENGINE FUEL

• Install the Power Steering pump & bracket assem-

bly.

Tighten:

• 10M bolts to 40 N

⋅m (4.1 kg⋅m/30 lb⋅ft)

• 8M  bolts  to  19  N

⋅m (1.9 kg⋅m/14 lb⋅ft)

• Lock nut to 27 N

⋅m (2.8 kg⋅m/20 lb⋅ft)

15. AC Generator Drive Belt

• Install AC generator drive belt and adjust belt ten-

sion.

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

kg/ 22 lb) force.

• Install fixing bolt and tighten bolts to the specified

torque.

Tighten:

• Generator fixing bolt to 40 N

⋅m (4.1 kg⋅m/30 lb⋅ft)

• Adjust Plate Fixing Bolt to 19 N

⋅m (1.9 kg⋅m/14 lb⋅ft)

16. A/C Compressor Drive Belt (A/C Model)

• Install A/C compressor drive belt and adjust belt

tension.

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

kg/22lb) 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)

4JG2

4JB1

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

• Install power steering pump drive belt and adjust

belt tension.

Legend

1. Pipe bracket
2. Lock nut
3. Clip

Drive Belt Deflection

mm (in)

8 (0.31) — 12 (0.47)

Drive Belt Deflection

mm (in)

8 (0.31) — 12 (0.47)

N6A3793E

Legend

1. A/C compressor drive belt
2. P/S oil pump drive belt
3. AC generator fan pulley drive belt

Legend

1. A/C compressor drive belt & P/S pump drive 

belt

2. AC generator & fan pulley drive belt

N6A3297E

N6A3295E

ENGINE FUEL 6C-51

• 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)

18. Fan Shroud

• Install the fan shroud and reservoir tank hose.

? 

19. 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:
Nut to 8 N

⋅m (0.8 kg⋅m/69 lb⋅in)

• Connect battery ground cable.
• Pour coolant.
• Start the engine and check coolant leakage.

Injection Timing Adjustment

• Set No. 1 cylinder to top dead center.
• Remove injection pump distributor head plug.
• Cancel wax CSD with the handle of a screw driver.
• Fit a dial gauge and set lift to 2 mm.

Measuring device: 5-8840-0145-0

• Set crankshaft damper pulley top dead center mark

about 45

° before top dead center from the pointer. 

• Set dial gauge in the “0” position.
• Turn the crankshaft a little clockwise and counter-

clockwise and see if the pointer is stable in the “0”
position.

• Turn the crankshaft in the normal direction and

read the measuring device’s indication at as fol-
lows.

Drive Belt Deflection

mm (in)

8 (0.31) — 12 (0.47)

N6A3223E

N6A3456E

N6A3457E

6C-52 ENGINE FUEL

• If it reads abnormal, loosen injection pump fixing

nut and pump bracket adjust bolt, make adjustment
by changing the pump mounting angle, and tighten
the nut and bolt to the specified torque where the
dial indicates the specified valve.

Tighten:

• Pump fixing nut to 24 N

⋅m (2.4 kg⋅m/17 lb⋅ft)

• Adjust bolt to 19 N

⋅m (1.9 kg⋅m/14 lb⋅ft)

• Remove the measuring device and tighten the dis-

tributor head plug to the specified torque.

Tighten:
17 N

⋅m (1.7 kg⋅m/12 lb⋅ft)

Caution:

• When installing the distributor head plug, be sure

to use new copper washer.

• Connect injection pipe.

• Fit pipe clip where specified.

Adjustment of Idling Speed

1. Pull the parking brake and lock the wheels.
2. Set the transmission gear to the neutral position.
3. Start the engine and idle it until the water tempera-

ture gets to 70 to 80

°C (158 to176°F).

4. Turn back the idling control button, and remove the

control cable from the control lever (injection
pump).

5. Set the engine tachometer.
6. Check the idling rotation.

When the idling rotation is outside the range of the
specified value, adjust it correctly.

1) Loosen the lock nut of the idling set bolt.
2) Rotate the idling set bolt to set the idling rota-

tion to the specified value.

4JB1

BTDC 14

°, BTDC 12° (′91/ 542A)

4JB1-TC

BTDC4

°

4JG2 (Belt Drive
Type)

ATDC 1

° (′91/ 542A)

TDC 0

° (′91/ 542B)

4JG2 (Gear
Drive Type) 

ATDC 2 (

′91/ 542A)

Legend

A. 4JB1
B. 4JG2 Gear drive type

C. 4JG2 Belt drive type

Measuring Device’s Indication

mm (in)

Standard

0.5 (0.0197)

N6A3458E

Specified value (rpm) = 

750 — 790 (4JB1)

700 — 740 (4JG2)

675 — 725 (4JH1-TC)

N6A3459E

N6A3460E

ENGINE FUEL 6C-53

3) Tighten the lock nut to lock the set bolt.
4) Check the tension of the control cable, and re-

move any slackening as required.

N6A3368E