Timing ISUZU TF SERIES 2004 Workshop Manual

6A – 2 ENGINE MECHANICAL
Disassembly ............................................................................................................... 6A- 47
Internal Parts........................................................................................................... 6A- 47
Major Components.............................................................................................. 6A- 47
Minor Components ............................................................................................. 6A- 56
Rocker Arm Shaft and Rocker Arm................................................................ 6A- 56
Cylinder Head .................................................................................................. 6A- 57
Piston and Connecting Rod ........................................................................... 6A- 59
Inspection and Repair................................................................................................ 6A- 61
Cylinder Head ......................................................................................................... 6A- 61
Rocker Arm Shaft and Rocker Arm ....................................................................... 6A- 68
Cylinder Body ......................................................................................................... 6A- 69
Camshaft ................................................................................................................. 6A- 77
Crankshaft and Bearing ......................................................................................... 6A- 79
Crankshaft Bearing Selection................................................................................ 6A- 83
Crankshaft Pilot Bearing........................................................................................ 6A- 85
Flywheel and Ring Gear ......................................................................................... 6A- 85
Piston....................................................................................................................... 6A- 86
Cylinder Head Gasket Selection............................................................................ 6A- 88
Connecting Rod ...................................................................................................... 6A- 90
Idler Gear Shaft and Idler Gear.............................................................................. 6A- 91
Timing Gear Case Cover ........................................................................................ 6A- 91
Reassembly ................................................................................................................ 6A- 93
Internal Parts........................................................................................................... 6A- 93
Minor Component ............................................................................................... 6A- 93
Rocker Arm Shaft and Rocker Arm................................................................ 6A- 93
Cylinder Head .................................................................................................. 6A- 94
Piston and Connecting Rod ........................................................................... 6A- 96
Positive Crankcase Ventilation (PCV) Valve ................................................. 6A- 99
Major Component................................................................................................ 6A- 101
Installation .................................................................................................................. 6A- 118
External Parts ......................................................................................................... 6A- 118
Lubrication System........................................................................................................ 6A- 126

6A – 4 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JA1T (L) 4JA1TC
Engine type
Combustion chamber type
Cylinder liner type
Timing gear train system Four-cycle, overhead valve, water cooled
Direct injection
Dry type, chrome plated
Gear drive
No. of cylinders-bore
stroke mm (in) 4 – 93
92 (3.66
3.62)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement cm3 (in3)
Compression ratio (to 1) 2,499(152.4)
18.5
Compression pressure Mpa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) Approximately 239 (527)
Fuel injection order 1 – 3 – 4 - 2
Fuel injection timing BTDC deg 8 -
Specified fuel type
Idling speed rpm

Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system JIS No. 2, DIN/EN590, GB252-1944 Diesel fuel
730  25 (A/C Off)
850  25 (A/C ON)
0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0

Injection pump type BOSCH distributor VE type BOSCH distributor VP44 type
Governor type Mechanical (Half all speed
type) Electronically controled
Injection nozzle type
Injection nozzle opening pressure Hole with 5 orifices

Mpa(kg/cm2/psi) 1st 19.1 (195 / 2,773) 1st 19.0 (194 / 2,755)
2nd (Reference)
25.527.0
(260275 / 3,7023,920) 2nd (Reference)
34.035.5
(347362 / 4,9365,154)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator

Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)

6A – 6 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JH1TC
Engine type Four-cycle, overhead valve, water cooled
Combustion chamber type Direct injection
Cylinder liner type
Timing gear train system Dry type, chrome plated
Gear drive
No. of cylinders-bore
stroke mm (in) 4 – 95.4
104.9 (3.76
4.13)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement liter
Compression ratio (to 1) 2,999
18.3
Compression pressure MPa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) MT : Approximately 249 (549)
AT : Approximately 236 (520)
Fuel injection order 1 – 3 – 4 - 2
Specified fuel type JIS No.2, DIN/EN590, GB252-1944 Diesel fuel
Idling speed rpm
700
25 (A/C OFF)
800
25 (A/C ON)
Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system
Injection pump type 0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0

BOSCH distributor VP44 type
Injection nozzle type
Injection nozzle opening pressure
MPa(kg/cm
2/psi)Hole with 5 orifices

1st 19.5 (199/2,828)
2nd (Reference) 34.335.8 (350365/4,9805,197)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator

Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)
Oil pump type
Oil filter type Gear
Cartridge paper element
Oil capacity lit (US/UK gal)
6.2 (1.64/1.36) (For 4
2)
7.0 (1.85/1.54) (For 4
4)
Oil cooler type Water cooled

ENGINE MECHANICAL 6A – 11
Timing Gear Case, Pulley Housing, Timing Gear, and Camshaft
N·m (kg·m/lb·ft)






RTW46AXF000601

ENGINE MECHANICAL 6A – 31
VALVE CLEARANCE ADJUSTMENT
1. Bring the piston in either the No. 1 cylinder or the No. 4
cylinder to TDC on the compression stroke by turning
the crankshaft until the crankshaft damper pulley TDC
line is aligned with the timing pointer.

014RY00014











2. Check the rocker arm shaft bracket nuts for
looseness.
Tighten any loose rocker arm shaft bracket nuts
before adjusting the valve clearance.

Rocker Arm Shaft Bracket Nut Torque N·m (kg·m /lb·ft)
54 (5.5/40)


014RY00015
8. Check for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.
If the No. 1 cylinder intake and exhaust valve push
rods are depressed, the No. 4 piston is at TDC on the
compression stroke.

014RY00016
Adjust the No.1 or the No. 4 cylinder valve clearances
while their respective cylinders are at TDC on the
compression stroke.
Valve Clearance (At Cold) mm (in)
0.4 (0.016)

9. Loosen each valve clearance adjusting screw as
shown in the illustration.
10. Insert a feeler gauge of the appropriate thickness
between the rocker arm and the valve stem end.


014RY00017


11. Turn the valve clearance adjusting screw until a slight
drag can be felt on the feeler gauge.
12. Tighten the lock nut securely.
13. Rotate the crankshaft 360.
14. Realign the crankshaft damper pulley TDC notched
line with the timing pointer.
15. Adjust the clearances for the remaining valves as
shown in the illustration.

ENGINE MECHANICAL 6A – 33
INJECTION TIMING ADJUSTMENT
(4JA1T(L) only)
1. Check that the notched line on the injection pump
flange is aligned with the front plate or the timing gear
case notched line.





2. Bring the piston in the No. 1 cylinder to TDC on the
compression stroke by turning the crankshaft until the
crankshaft pulley TDC line is aligned with the timing
mark.
Note:
Check for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.
RTW46ASH000601
3. Disconnect the injection pipe from the injection pump
4. Remove one bolt from the distributor head.
5. Install the static timing gauge.
The probe of the gauge should be depressed inward
approximately 2 mm (0.079 in).
Static Timing Gauge: 5-8840-0145-0 (J-28827)

6. Rotate the crankshaft to bring the piston in the No. 1
cylinder to a point 30 - 40 BTDC.
7. Set the timing gauge needle to zero.
8. Move the crankshaft pulley slightly in both directions to
check that the gauge indication is stable.

6A – 34 ENGINE MECHANICAL



RTW46ASH000701
9. Turn the crankshaft clockwise and read the gauge
indication when the crankshaft pulley timing mark (8)
is aligned with the pointer.

Injection Timing : BTDC 8  2

Standard Reading mm (in)
0.5 (0.02)

If the injection timing is outside the specified range,
continue with the following steps.


10. Loosen the injection pump fixing nuts and bracket
bolts.
11. Adjust the injection pump setting angle.
When large than standard
value When smaller than standard
value
R A


A: Move the injection pump toward the engine.
R: Move the injection pump away from the engine.

ENGINE CONTROL (4JA1T(L) only)
Idling Speed Adjustment
1. Set the vehicle parking brake and chock the drive
wheels.
2. Place the transmission in neutral.
3. Start the engine and allow it to idle until the coolant
temperature reaches 70 - 80C (158 - 176F).


4. Disconnect the engine control cable from the control
lever.
5. Set a tachometer to the engine.
6. Check the engine idling speed.
If the engine idling speed is outside the specified
range, it must be adjusted.
Engine Idling Speed : 730  25 rpm


Idling Speed Adjustment
1. Loosen the idling set screw lock nut
on the injection
pump idling set bolt.
2. Adjust the idling speed to the specified range by
turning the idling set bolt
.
3. Lock the engine set nut

with the idling set bolt lock
nut.
4. Check that the idling control cable is tight (free of
slack). If required, remove the slack from the cable.

6A – 48 ENGINE MECHANICAL







RTW46ALF000101


Disassembly Steps-2
9. Crankshaft damper pulley
10. Timing gear case cove
11. Water pump
12. Idle gear "B" and shaft
13. Idle gear "A"
14. Idle gear shaft
15. Crankshaft timing gear
16. Injection pump

ENGINE MECHANICAL 6A – 49

014R300005


Disassembly Steps-3
17. Flywheel 27. Piston and connecting rod with
18. Crank case upper bearing
19. Oil pump with oil pipe 28. Crankshaft bearing cap with
20. Camshaft timing gear lower bearing
21. Camshaft thrust plate 29. Crankshaft thrust bearing
22. Camshaft 30. Crankshaft
23. Timing gear case 31. Crankshaft upper bearing
24. Cylinder body rear plate 32. Tappet
25. Piston cooling oil jet 33. Crankshaft rear oil seal
26. Connecting rod bearing cap with 34. Cylinder body
lower bearing

ENGINE MECHANICAL 6A – 51

10. Timing Gear Case Cover
The timing gear case is tightened together with the
injection pump at the 6 points indicated by the arrows in
the illustration.

11. Water Pump



12. Idle Gear B and shaft
Before removing the idle gear B, install bolt (M6,L=30) to
the hole marked with an arrow in the illustration to hold the
scissor gear in place.



13. Idler Gear "A"
1. Measure the camshaft timing gear backlash and the
crankshaft timing gear backlash before removing the
idler gear.
2. Measure the idler gear end play before removing the
idler gear.

NOTE:
Refer to the following items for details on the backlash
and end play measurement procedures.



Timing Gear Backlash Measurement
1. Set a dial indicator to the timing gear to measured.
Hold both the gear to be checked and the adjusting
gear stationary.
2. Move the gear to be checked as far as possible to
both the right and the left.
Take the dial indicator reading.
If the measured value exceeds the specified limit, the
timing gear must be replaced.

Timing Gear Backlash mm (in)
Standard Limit
0.10 - 0.17 (0.0039 - 0.0067) 0.30 (0.012)
020L200006
020L200020
020RY00019
020RY00020