Isuzu engine 4j series. Manual - part 56

6A1 – 92  4JB1/4JB1T/4JB1TC/4JG2 - ENGINE

•

Block the crankshaft with a piece of hard wood to
prevent the flywheel form turning.

•

Apply a coat of engine oil to the threads of the flywheel
bolts.

•

Align the flywheel with the crankshaft dowel pin.

•

Tighten the flywheel bolts to the specified torque in two
steps using the Angular Tightening Method.
Follow the numerical order shown in the illustration.

Flywheel Bolt Torque

N∙m (kg∙m/lb∙ft)

1st Step

2nd Step

59 (6.0/43)

60° - 90°

11. Water Pump Assembly

•

Fit the O-ring to the water pump body.

•

Remove the water pump assembly and tighten bolts to
the specified torque.

Water Pump Bolt Torque

N∙m (kg∙m/lb∙in)

                                                                                                                   

20 (2.0/14)

                                                                                                                   

10a. Timing Pulley Housing

•

Install the timing pulley housing the cylinder body.
Take care not to twist the front oil seal.

•

Tighten the timing pulley housing together with the
timing pulley housing gasket to the specified torque.

Timing Pulley Housing Bolt Torque

N∙m (kg∙m/lb∙ft)

                                                                                                                   

19 (1.9/14)

                                                                                                                   

•

Cut away the flash from the gasket.

10. Timing Gear Housing

•

Install the timing gear housing the cylinder body.

•

Tighten the timing gear housing together with the
timing gear housing gasket to the specified torque.

Timing Gear Housing Bolt Torque

N∙m (kg∙m/lb∙ft)

                                                                                                                   

19 (1.9/14)

                                                                                                                   

•

Cut away the flash from the gasket.

9. Front Oil Seal (Belt Drive Model)

•

Install oil seal using special tool.
Front Oil Seal Installer: 5-8840-2361-0

Notes:

Wipe off rust and scraps clean from the press-in
portion of the oil seal.
Take note of the press-in direction of the oil seal.
1)  With the oil seal attached to the sleeve, put it in the

front end of the crankshaft.

6A1-92-2.tif

6A1-92-3.tif

6A1-92-4.tif

6A1-92-1.tif

4JB1/4JB1T/4JB1TC/4JG2 – ENGINE  6A1 – 93

2) With the edge of the oil seal attached securely to the

crankshaft, tighten it with the center bolt until the
sleeve hits securely against the reference plane at the
front end of the crankshaft.

3) Remove the sleeve.
4) After pressing in the oil seal, check the measurement

of the oil seal.

Standard

mm (in)

                                                                                                                   

0.6 - 1.2 (0.024 - 0.047)

                                                                                                                   

8. Piston and Connecting Rod Assembly

7. Piston Cooling Oil Pipe

Above works refer to “PISTON” Section in this manual.

6. Oil Pump Assembly

5. Oil Pan Assembly

Above works refer to “OIL PUMP AND OIL PAN” Section
in this manual.

4a. Timing Belt (Belt Drive Model)

12) Camshaft timing pulley

Above works refer to “CAMSHAFT AND TAPPET”
Section in this manual.

11) Injection pump
10) Injection pump timing pulley

Above works refer to “CYLINDER BLOCK
ASSEMBLY” Section in this manual.

9) Crankshaft timing pulley
•

Use the crankshaft timing pulley installer to install the
timing pulley.

•

The timing pulley flange must be facing the cylinder
body.
Crankshaft Timing Pulley Installer: 5-8522-0020-0

8) Crankshaft timing pulley center
•

Install the crankshaft pulley center.

•

Use the fixing wrench to prevent the crankshaft from
turning.
Fixing Wrench: 5-8840-0161-0

•

Tighten the crankshaft pulley center bolt to the
specified torque.

Crankshaft Pulley Center Bolt Torque

N∙m (kg∙m/lb∙ft)

                                                                                                                   

206 (21/152)

                                                                                                                   

7) Timing belt
6) Flange: camshaft pulley
5) Flange: injection pump pulley
4) Timing pulley lower cover
3) Timing pulley upper cover

6A1-93-1.tif

6A1-93-2.tif

6A1 – 94  4JB1/4JB1T/4JB1TC/4JG2 - ENGINE

2) Crankshaft damper pulley
1) Cooling fan assembly

Above works refer to “TIMING GEAR (Belt Type)”
Section in this manual.

4. Timing Gear (Gear Drive Model)

11) Crankshaft gear
•

Install the crankshaft gear.

•

Use the crankshaft gear installer 

!

 to install the

crankshaft gear 

"

.

•

The crankshaft gear timing mark ("X-X") must be
facing outward.
Crankshaft Gear Installer: 9-8522-0020-0

10) Camshaft timing gear
9) Injection pump
8) Idler gear "B" and shaft
7) Idle gear
6) Timing gear oil pipe
5) Timing gear case cover
4) Noise cover spacer
3) Noise shield cover
2) Crankshaft damper pulley
1) Cooling fan assembly

Above works refer to “TIMING GEAR (Gear Type)”
Section in this manual.

3. Cylinder Head Assembly and Gasket

12) Cylinder head gasket
11) Cylinder head assembly
10) Push rod
9) Rocker arm shaft assembly
Valve Clearance Adjustment
8) Cylinder head cover
7) By-pass hose
6) Oil cooler water pipe (Oil Cooler Model)
5) Oil level gauge guide tube
4) Glow plug harness connector
3) PCV hose
2) Fuel leak off pipe
1) Injection pipe

Above works refer to “CYLINDER HEAD ASSEMBLY
AND GASKET” Section in this manual.

6A1-94-1.tif

4JB1/4JB1T/4JB1TC/4JG2 – ENGINE  6A1 – 95

2. Engine Assembly

13) Support rubber
12) Front exhaust pipe
11) Vacuum pump hose
10) Actuator vacuum hose (Exhaust Brake Model)
9) Power steering pump & bracket assembly (Power

Steering Model)

8) A/C compressor assembly (A/C Model)
7) Oil pressure switch harness
6) Fuel hose
5) Glow plug harness
4) Engine control cable
3) Heater hose
2) Intake air duct
1) Radiator assembly

Above works refer to “ENGINE ASSEMBLY” Section in
this manual.

1. Transmission and Clutch Assembly

2) Clutch
1) Transmission

Above works refer to “ENGINE ASSEMBLY” Section in
this manual.