Isuzu engine 4j series. Manual - part 67

6C - 12  ENGINE FUEL

•

Install retaining nut and tighten nut to the specified
torque.

N∙m (Kg∙m/lb∙ft)

                                                                                                                   

39 (4.0/32)

                                                                                                                   

ADJUSTMENT OF INJECTION OPENING
PRESSURE (4JG2 Engine)

•

Set nozzle holder assembly on a nozzle tester.

•

Apply hydraulic pressure by operating tester handle,
and make sure fuel cam be injected under the
following pressure.

Kpa (Kg/cm

2

/psi)

                                                                                                                   

14,710 (150/2,133)

                                                                                                                   

CAUTION

•

If not injected under the specified pressure, adjust with
adjusting shim.

 Ref.

Types are available in the 1.0 mm - 1.75 mm
thickness range (on a 0.01 mm basis).

•

Unless extremely deformed spray in seen, there is no
problem.

CAUTION

•

The spray condition, when judged with a nozzle tester,
is deemed as normal so long as the spray form is not
excessively deformed.

Oil tight test (4JG2 Engine)

1) After completion of the adjustment of injection

pressure, wipe off light oil at the tip of the nozzle with
waste.

2) With pressure 1,961 Kpa (20 kg/cm

2

/284 psi) less than

the specified injection pressure applied, check to see if
an oil drop trickles off the tip of the nozzle within 10
seconds after application of pressure. (There is no
problem with the nozzle when oil gathers at the tip, but
does not drop off.)

3) When an oil drop trickles, clean the nozzle thoroughly.

Then reassemble it to check for any dropping of oil.
When oil still drops, change it with a new one.

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ENGINE FUEL  6C - 13

INSTALLATION (4JG2 Engine)

CAUTION

•

Nozzle and assembling should be as illustrated.

•

Use new heat shield and new corrugated washer.

3. 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 (

φ

2) 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

2. Leak Off Pipe

•

Mount using a new copper washer

•

Tighten nut to the specified torque.

Pipe Nut Torque

N∙m (Kg∙m/lb∙ft)

                                                                                                                   

29 (3.0/22)

                                                                                                                   

1. Injection Pipe

•

Connect injection pipe to nozzle holder.

•

Tighten the injection pump side.

Sleeve Nut Torque

N∙m (Kg∙m/lb∙ft)

                                                                                                                   

29 (3.0/22)

                                                                                                                   

•

Fit pipe clip in specified position.

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6C - 14  ENGINE FUEL

4-1 Injection Nozzle (Two spring nozzle holder)
(4JB1-TC only)

The two-spring nozzle holder has been developed to
reduce NOx (Nitrogen Oxides) and particulates from direct
injection diesel engine exhaust.

DISASSEMBLY

1. Retaining nut
2. Nozzle & pin
3. Spacer & pin
4. Lift piece
5. Spring seat
6. Push rod
7. Shim (Second nozzle opening pressure adjustment)
8. Second spring
9. Collar
10. Spring seat
11. First spring
12. Shim (First nozzle opening pressure adjustment)
13. Nozzle holder body
14. Eye bolt
15. Gasket

(1) Before disassembly remove carbon deposit from

nozzle and nozzle holder using a wire brush and wash
the outside nozzle holder assembly.

Caution:

Do not touch nozzle holes with the wire brush
during cleaning it.

(2) Disassemble the nozzle holder assembly to numerical

order.

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ENGINE FUEL  6C - 15

REASSEMBLY AND OPENING
PRESSURE ADJUSTMENT (4JB1-TC
only)

1. Nozzle holder body
2. Shim (First opening pressure adjustment)
3. First spring
4. Spring seat
5. Collar
6. Second spring
7. Push rod
8. Shim (Second opening pressure adjustment)
9. Spring seat
10. Lift piece
11. Spacer & pin
12. Nozzle & pin
13. Retaining nut
14. Gasket
15. Eye bolt

The nozzle holder is adjusted as the components are
reassembled in the sequence above.
As adjustment of the two-spring nozzle holder is made in
hundredths of a millimeter, clean the parts thoroughly in light oil
to completely remove any dirt or foreign matter.

REASSEMBLY AND ADJUSTMENT PROCEDURE

1

First nozzle opening pressure adjustment

Adjust the first nozzle opening pressure using the shim.

2

Full needle valve lift confirmation

Confirm the full needle valve lift in accordance with the
closed method.

3

Pre-lift confirmation

Confirm pre-lift in accordance with the closed method.

CAUTION:

If not as specified, replace the nozzle assembly, lift
piece, pins and spacer using the nozzle service kit.

4

Second nozzle opening pressure

confirmation

Confirm the second nozzle opening pressure in accordance
with the closed method.

5

Second nozzle opening pressure

adjustment

Adjust the second nozzle opening pressure using the shim.

6

Final inspection

Confirm the condition of the fuel spray with the nozzle and
nozzle holder assembled.

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