Isuzu engine 4j series. Manual — part 38

6A1 – 20 4JB1/4JB1T/4JB1TC/4JG2 - ENGINE

VALVESTEM OIL CONTROLLER & VALVE SPRING

REMOVAL

Preparation:

•

Disconnect battery ground cable.

1. Cylinder Head Cover

2. Rocker Arm Shaft Assembly

•

Loosen bolts and nuts of rocker shaft

•

Bracket by turns and removal rocker shaft assembly.

3. Valve Spring

•

Apply compressed air to cylinder from the glow plug
hole hold the valve in place.

•

Using special tool, compress valve spring and removal
split collar.
Valve spring compressor: 9-8523-1423-0 (J-29760)

CAUTION

•

Put removed valve springs in the order of cylinder
number.

6A1-20-1.tif

6A1-20-2.tif

Removal steps

1. Cylinder head cover
2. Rocker arm shaft Assembly
3. Valve spring
4. Valve guide oil seal

Installation steps

To install, follow the removal
steps in the reverse order.

4JB1/4JB1T/4JB1TC/4JG2 – ENGINE 6A1 – 21

4. Valve Guide Oil Seal

•

Removal valve guide oil seal by pliers.

CAUTION

•

Removed oil controller should not be reused.

INSTALLATION

4. Valve Guide Oil Seal

•

Install new valve guide oil seal in valve.

•

Guide using special tool.
Special tool: 5-8840-2033-0

3. Valve Spring

•

Attach the valve spring to the upper spring seat.

CAUTION

•

The painted area of the valve spring should be facing
toward.

•

Apply compressed air to cylinder from the glow plug
hole to hold the valve in place.

•

Install split collar by special tool.
Valve spring compressor: 9-8523-1423-0 (J-29760)

2. Rocker Shaft Assembly

•

Install rocker arm shaft with a larger oil hole (

φ

4) to the

front of engine.

•

Align fixing bolt with not of rocker arm shaft and
tighten fixing bolt to the specified torque.

N∙m (kg∙m/lb∙ft)

54 (5.5/40)

•

Valve clearance adjustment

6A1-21-1.tif

6A1-21-2.tif

6A1-21-3.tif

6A1-21-4.tif

6A1 – 22 4JB1/4JB1T/4JB1TC/4JG2 - ENGINE

Valve Clearance Adjustment

Above works refer to “ROCKER ARM SHAFT
ASSEMBLY” Section in this manual.

1. Cylinder Head Cover

•

Apply engine oil to the rocker arms and the valve
spring.

•

Install the cylinder head cover gasket to the cylinder
head cover.
The gasket must be perfectly smooth with no loose
areas.

•

Install cylinder head cover and tighten bolt to the
specified torque.

Head Cover Bolt Torque

N∙m (kg∙m/lb∙in)

13 (1.3/113)

•

Connected PCV hose.

•

Connect battery ground cable.

6A1-22-1.tif

4JB1/4JB1T/4JB1TC/4JG2 – ENGINE 6A1 – 23

TIMING GEAR (4JB1, 4JB1TC, 4JG2 Gear Type)

REMOVAL

Preparation:

•

Disconnect battery ground cable.

•

Drain coolant.

1. Fan Shroud

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

•

Loosen power steering pump mounting bolt and adjust
bolt, and remove the drive belt.

3. AC Generator Drive Belt

•

Loosen AC Generator mounting bolt (under side) and
adjust plate lock bolt, and remove the drive belt.

4. Cooling Fan Assembly

•

Remove clamp nut, and remove cooling fan assembly,
distant pipe, and fan pulley.

5. Crankshaft Damper Pulley

6. Noise Shield Cover

6A1-23-1.tif