engine ISUZU TROOPER 1998 Service Repair Manual

6A Ð 46 ENGINE MECHANICAL
Cylinder bore
diameter average
1Liner outside
diameterLiner
Grade
97.001-97.010
(3.8189-3.8193)
97.011-97.020
(3.8193-3.8197)
97.021-97.030
(3.8197-3.8201)
97.031-97.040
(3.8201-3.8205)97.011-97.020
(3.8193-3.8197)
97.021-97.030
(3.8197-3.8201)
97.031-97.040
(3.8201-3.8205)
97.041-97.050
(3.8205-3.8209)
2
3
4
mm (in.) 2) Calculate the average value of the four measurements
to determine the correct cylinder grade.
3) Consult the following table with the resultant diameter
for the correct liner application.
Cylinder Liner Installation
1. Cylinder Liner Installation Using The Special Tool.
1) Use new kerosene or diesel oil to thoroughly clean
the cylinder liners and horse.
2) Use compressed air to blow-dry the cylinder liner
and bore surfaces.
Cylinder Liner Installer : 5-8840-2313-0
NOTE:
All foreign material must be carefully removed from the
cylinder liner and the cylinder bore before installation.
3) Insert the cylinder liner 1 into the cylinder body 2
from the top of the cylinder body.

ENGINE MECHANICAL 6A Ð 47
4) Set the cylinder liner installer  to the top of the
cylinder liner.
Position the cylinder body so that the installer center
is directly beneath the bench press shaft center Ã.
Cylinder Liner Installer: 5-8840-2313-0
NOTE:
Check that the cylinder liner is set perpendicular to the
bench press and that there is no wobble.
5) Use the bench press to apply a seating force of
4,900 N (500kg/1,102.5 lb) to the cylinder liner.
6) Apply a force of 24,500 N (2,500 kg /5,512.5 lb) to fully
seat the cylinder liner.
7) After installing the cylinder liner, measure the cylin-
der liner projection.
8) After installing the cylinder liner, measure the cylin-
der liner projection.
Refer to ÒCylinder Liner Projection InspectionÓ in
this Section
Measure the cylinder liner bore inside diameter and
select the appropriate piston grade.
CAUTION:
After installed the piston assembly. Check and see that there
is appropriate clearance between pistons and oil jet pipes by
rotating crankshaft slowly.
16. Crankshaft
·Install the main bearings to the cylinder body and
the main bearing caps.
·Be sure that they are positioned correctly.
·Apply new engine oil to the upper and lower main
bearing faces
·Carefully mount the crankshaft.
This illustration 4JG2-T
REASSEMBLY
18. Cylinder Block
17. Piston Cooling Oil Pipe
1) Fix the oil jet pipes with knock pins on the cylinder
block.
2) Install the oil pipe for piston cooling in the cylinder
block, tightening a relief valve 1 and four joint bolts
2 to the specified torque.
Relief valve fixing bolt
29 (3.0/22)
Oil pipe fixing bolts
19 (1.9/14)
8 (0.8/69 lb·in.) M8
M6N·m (kg·m/lb·ft)
N·m (kg·m/lb·ft)

6A Ð 48 ENGINE MECHANICAL
·Apply engine oil to the thrust washer.
·Assemble the thrust washer to the No. 3 bearing
journal. The oil grooves must face the crankshaft.
15. Main Bearing Cap Assembly
·Apply the recommended liquid gasket or its equiva-
lent to the No. 5 crankshaft bearing cap cylinder
body fiting surfaces at points 1 and 2 shown in the
illustration.
NOTE:
Be sure that the bearing cap fitting surface is completely
free of oil before applying the liquid gasket.
Do not allow the liquid gasket to obstruct the cylinder
thread holes and bearings.
·Install the bearing caps with the bearing cap head
arrow mark facing the front of the engine.
·Apply engine oil to the crankshaft bearing cap bolts.
·Tighten the crankshaft bearing cap bolts to the
specified torque a little at a time in the sequence
shown in the illustration.
NOTE:
Check to see that the crankshaft turns smoothly by rotating
it manually.
·Apply the recommended liquid packing or its equiva-
lent to the No. 5 crankshaft bearing cap 3 as shown
in the illustration.
Install the arch packing 4 to the No. 5 bearing cap.
NOTE:
Take care to install the arch packing in the groove of bearing
cap correctly.
Take care not to scratch the arch packing outer surface.
167 (17.0/123)N·m (kg·m/lb·ft)

ENGINE MECHANICAL 6A Ð 49
14. Piston Assembly
·Refer to ÒPiston and connecting rodÓ in this Section.
13. Tappet
12. Timing Gear Case
1) Install the timing gear case to the cylinder body.
NOTE:
Take care not to twist the front oil seal.
2) Tighten the timing gear case bolt together with the
timing gear case gasket to the specified torque.
19 (1.9/14)N·m (kg·m/lb·ft)
3) Cut away the gasket protruding above the fitting
surfaces (as shown in the illustration).
11. Crankshaft Front Oil Seal
·Use the installer to install the front oil seal 1 to
the gear case cover 2.
Oil Seal Installer: 5-8840-2061-0
Note the oil seal installation depth 3 shown in
the illustration.
Depth 3 = 1 mm (0.039 in.)
10. Camshaft
·Refer to ÔCamshaft, TappetÕ in Section 6A.
9. Camshaft Thrust Plate
·Install the thrust plate to the cylinder body and
tighten the thrust plate bolts to specified torque.
18 (1.8/13)N·m (kg·m/lb·ft)

6A Ð 50 ENGINE MECHANICAL
8. Camshaft Timing Gear
1) Install the camshaft timing gear to the camshaft.
The timing gear mark ("Y - Y") must be facing
outword.
2) Tighten the timing gear to the specified torque.
64 (6.5/47)N·m (kg·m/lb·ft)
7. Oil Pump Assembly
·Refer to ÔOil pumpÕ in Section 6A2.
6. Crankcase Assembly
·Refer to ÔCrankcaseÕ in Section 6A2.
5. Crankshaft Rear Oil Seal
1) Tighten the adapter to the crankshaft rear and
section with 2 bolts.
2) Insert the oil seal into the peripheral section of the
adapter,
3) Insert the sleeve into the adapter section, and 1)
tighten it with a bolt (M12 x 1.75L = 70) until the
adapter section hits the sleeve.
4) Remove the adapter and the sleeve.
5) With the seal pressed in, check the dimension of
the oil seal section.
Standard Dimension = 12.5 ± 0.3 mm
Oil Seal Installer: 5-8840-2359-0
4. Cylinder Block Rear Plate
·Tighten the cylinder block rear plate fixing bolt to the
specified torque
82 (8.4/61)N·m (kg·m/lb·ft)
3. Flywheel
·Refer to ÔCrankshaftÕ in Section 6A.
2. Cylinder Head Gasket
1. Carefully remove carbon deposits and gasket
residue from the piston top face and the cylinder
body upper surface.

ENGINE MECHANICAL 6A Ð 51
2. Use a dial indicator to measure the piston head
projection at measuring points 1 and 3 on the
piston head and measuring points 2 and 4 on
the cylinder body.
Do this for each cylinder.
3. Note the highest measured value.
This will determine the cylinder head gasket
thickness.
Piston head projection must be within the range
shown in the above table.
4. Select a cylinder head gasket of the appropriate
thickness.
The difference between the highest measured pis-
ton head projection and the lowest measured piston
head projection must not exceed mm (in).
1. Cylinder Head Assembly
·Refer to Section 6A2 ÔCylinder headÕ
0.658 ~ 0.814 (0.0259 ~ 0.0320)
mm (in) Piston Head Projection
Grade
markAverage piston
projection
Gasket
thickness
(Reference)
A 0.658-0.712 (0.0259-0.0281) 1.60 (0.0630)
B 0.713-0.758 (0.0281-0.0299) 1.65 (0.0650)
C 0.759-0.813 (0.0299-0.0320) 1.70 (0.0670)
mm (in)

6A Ð 52 ENGINE MECHANICAL
MEMO

4JG2-NA/4JG2-TURBO ENGINE 6A2 Ð 1
SECTION 6A2
4JG2-NA/4JG2-TURBO ENGINE
CONTENTS
PAGE
General Description ........................................................................\
............................................. 6A2- 1
Engine Mount (RH) ........................................................................\
...................................... .... 6A2- 3
Engine Mount (LH) ........................................................................\
...................................... .... 6A2- 4
Intercooler (4JG2-T only) ........................................................................\
.............................. .. 6A2- 5
Cylinder Head Cover ........................................................................\
.................................... ... 6A2- 6
Inlet Manifol d........................................................................\
........................................ .......... .6A2- 8
Exhaust Manifol d........................................................................\
...................................... ..... . 6A2-10
Turbo Charger (4JG2-T only) ........................................................................\
.......................... 6A 2-11
Timing Gear ........................................................................\
............................................ ......... 6A2-15
Valve Stem Oil Seal and Valve Spring ........................................................................\
.......... 6A2-21
Rocker Arm Shaft Assembly ........................................................................\
.......................... 6A2- 24
Cylinder Head ........................................................................\
.......................................... ........ 6A2-26
Crankcase ........................................................................\
.............................................. ........... 6A2-31
Oil Cooler ........................................................................\
............................................. ............. 6A2-34
Oil Pump Assembly ........................................................................\
...................................... ... 6A2-36
Piston, Piston Ring and Connecting Rod ........................................................................\
...... 6A2-37
Crankshaft and Main Bearing ........................................................................\
......................... 6A2 -39
Front Oil Seal ........................................................................\
......................................... .......... 6A2-45
Rear Oil Seal ........................................................................\
.......................................... .......... 6A2-46
Engine Assembly ........................................................................\
........................................ ..... 6A2-48
GENERAL DESCRIPTION

6A2 Ð 2 4JG2-NA/4JG2-TURBO ENGINE
RECARD Comet V Type swirl combustion chamber which
provides superior driving performance, fuel economy and
silent combustion over a wide range of driving
conditions, is applied.
The cylinder head gasket is of laminated steel sheets.
Three grades of the gasket according to the measured
piston head projection from the cylinder block are
provided to give the engine a minimum compression
ration fluctuation.
The cylinder head fixing blots, flywheel bolts and con-
necting rod fixing bolts are tightened by the angular
Tightening Method.
The chrome plated steel dry type (Chromard) cylinder
liners provide the highest durability.
Auto-thermatic pistons having steel struts with 0.7 mm
offset from the piston pin center line, ate applied to
reduce thermal expansion and resulting engine noise
when the engine is cold.
The crankshaft bearings and connecting rod bearings are
of aluminum having a high bearing surface.
These bearing are especially sensitive to foreign material
such as metal scraps. So, it is very important that the oil
ports and other related surfaces are kept clean and free of
foreign material.
Crank shaft bearing selection for optimum bearing and
journal clearance is applied to reduce vibration and noise.
As tufftriding (Nitrizing treatment) is applied to increase
crankshaft strength, crankpins and journals should not be
reground.
An oiling jet device for piston cooling is provided in the
lubricating oil circuit from cylinder block oil gallery via a
check valve.
Take care not to damage any oiling jet when removing
and installing piston and connecting assembly.
The DFI (Double Formation Injection) Pintaux Type
injection nozzle having a sub-injection hole is applied.
This nozzle contributes to substantially minimize the
diesel knocking sound noticeable in the cold engine idling
operation.
Install the injection nozzle, directing the sub-injection hole
to the specified direction.
QOS III preheating system which features a quick-on glow
plug with thermometer control of the glowing time and
the afterglow time function, is applied.

4JG2-NA/4JG2-TURBO ENGINE 6A2 Ð 3
ENGINE MOUNT (RH)
REMOVAL
Preparation:
·Battery ground cable
·Support engine
·Support vehicle
1. Front Tire
2. Dust Cover
3. Engine Mount
·Remove fixing be its from cylinder body and
chassis frame.
INSTALLATION
3. Engine Mount
40 (4.1/30)
N·m(kg·m/lb·ft) Cylinder body side
40 (4.1/30)
N·m(kg·m/lb·ft) Chassis frame side
·Tighten the fixing bolts to the specified torque
2. Dust Cover
1. Front Tire
118 (12.0/87)N·m(kg·m/lb·ft)