Isuzu engine 4j series. Manual — part 18

6A – 8

GENERAL ENGINE MECHANICAL

3) Spring lower seat

4) Valve stem oil seal

•

Install a new oil controller in the valve.

•

Guide using special tool
Oil seal installer: 5-8840-2003-0

5) Valve

•

Apply engine oil to the outside of the valve stem before
installing it.

6) Valve Spring

•

Attach the valve spring to the upper spring seat.

CAUTION
•

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

•

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)

7) Split Collar

•

Use a spring compressor to push the valve spring into
position.

•

Install the spring seat split collar.

•

Set the split collar by tapping lightly around the head of
the collar with a rubber hammer.

Valve spring compressor: 9-8523-1423-0 (J-29760)

5. Push Rod

4. Rocker Arm Shaft and Rocker Arm

•

Tighten rocker arm shaft fixing bolts

N∙m (kg∙m/lb∙ft)

54 (5.5/40)

3a. Glow Plug and Glow Plug Connector (4JB1/4JB1T

only)

3. Glow Plug and Glow Plug Connector

•

Tighten glow plugs

N∙m (kg∙m/lb∙ft)

23 (2.3/17)

6A-7-3.tif

6A-8-1.tif

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GENERAL ENGINE MECHANICAL 6A – 9

2a. Injection Nozzle Holder (4JB1/4JB1T/4JB1TC only)

1) Install the injection nozzle gasket

!

and the O-ring

"

to the injection nozzle holder

#

.

Be sure that the O-ring fits snugly in the injection
nozzle groove.

2) Apply engine oil to the cylinder head nozzle holder

hole.

3) Install the nozzle holder together with the nozzle holder

bracket

$

to the cylinder head.

N∙m (kg∙m/lb∙ft)

37 (3.8/27)

2. Injection Nozzle (4JG2 only)

•

Lightly tighten the holder nut to suck extent that the
nozzle holder can turn one word and one word.

•

Set positioning confirmation drilled hole (ø2) within a
nozzle turning angle of ±5° against the cylinder head-
side positioning boss.

•

Apply a wrench as illustrated and tighten the holder nut
to the specified torque using a special tool.

CAUTION
•

After tightening the holder nut, make sure that the
drilled hole makes ±5° or smaller with the cylinder
head-side positioning boss.

•

When mounting leak off pipe, injection nozzle and
pipe, clean then with air so that dust may not
enter.

Nozzle Fixing Torque

N∙m (kg∙m/lb∙ft)

64 (6.5/47)

Wrench: Nozzle holder 5-8840-0259-0

1. Thermostat Housing Assembly

•

Tighten thermostat housing assembly fixing bolt.

N∙m (kg∙m/lb∙ft)

19 (1.9/14)

6A-8-3.tif

040LX016.tif

6A-9-1.tif

6A – 10

GENERAL ENGINE MECHANICAL

VALVE SPRING, VALVE GUIDE OIL SEAL, VALVE GUIDE, PUSH ROD

DISASSEMBLY

1. Rocker Arm Assembly

2. Split Collar

Using special Tool, compress valve spring
Valve spring compressor: 9-8523-1423-0 (J-29760)

3. Valve Spring

4. Valve

5. Valve Guide Oil Seal

6. Valve Guide

Valve Guide Replacer: 9-8523-1212-0

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6A-10-1.tif

GENERAL ENGINE MECHANICAL 6A – 11

INSPECTION AND REPAIR

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

Valve spring

CAUTION:

Visually inspect the valve springs and replace them if
damage or abnormal wear is evident.

1. Free height

•

Measure the free height of the springs. The springs
must be replaced if the height is below the specified
limit.

Free Height

mm (in)

Standard

Limit

48.0 (1.891)

47.100 (1.8560)

2. Squareness

•

Measure the valve spring squareness with a steel
square.

•

Replace the valve springs if the measured value
exceeds the specified limit.

Limit

mm (in)

1.7 (0.067)

3. Spring tension

•

Use spring tester to compress the springs to the
installed height. Measure the compressed spring
tension.
Replace the springs if the measured tension is below
the specified limit.

Tension

N (kg/lb)

Standard

Limit

At installed height

38.9 mm (1.5 in)

296.2 (30.2/66.6)

257.9 (26.3/57.9)

Valve Guide

CAUTION:

Taking care not to damage the valve seat contact
surface, when removing carbon adhering to the valve
head.

Carefully inspect the valve stem for scratching or
abnormal wear. If these conditions are present, the
valve and the valve guide must be replaced as a set.

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