1998 ISUZU TROOPER Cylinder head

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)

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.

6A2 Ð 6 4JG2-NA/4JG2-TURBO ENGINE
CYLINDER HEAD COVER
REMOVAL
Preparation:
·Disconnect battery ground cable.
1. Air Cleaner Cover & Air Duct (4JG2-T only)
·Disconnect two air hose.
·Release clips and bands and remove air cleaner
cover.
2. Intercooler Assembly (4JG2-Tonly)
·(Refer to intercooler removal steps in this section)
3. Heater and Oil Cooler Pipe Fixing Bolts
·Remove fixing bolts from.
4. Oil Level Gauge Tube
5. Cylinder head cover

4JG2-NA/4JG2-TURBO ENGINE 6A2 Ð 7
INSTALLATION
5. Cylinder Head Cover
·Apply engine oil to the rocker arms and the valve
springs.
·Install the cylinder head cover gasket to the
cylinder head cover.
·The gasket must be perfectly smooth with no
loose areas.
·Tighten the cylinder head cover nuts to the
specified torque in the numerical order.
13 (1.3/113 lb·in)N·m(Kg·m/lb·in)
4. Oil Level Gauge Tube
19 (1.9/14)N·m(Kg·m/lb·ft)
Bolt
3. Heater and Oil Cooler Pipe Fixing Bolts
2. Intercooler Assembly (4JG2-T Only)
·(Refer to intercooler installation steps in this
section.)
1. Air Cleaner Cover & Air Duct

4JG2-NA/4JG2-TURBO ENGINE 6A2 Ð 21
VALVE STEM OIL SEAL & VALVE SPRING
REMOVAL
Preparation
·Disconnect battery ground cable.
1. Air cleaner Cover & Air Duct (4JG2-T Only)
·Disconnect air hoses.
·Release clips and bands and remove air cleaner
cover.
2. Intercooler Assembly (4JG2-T Only)
·(Refer to intercooler removal steps in this section)
3. Oil Level Gauge Tube
4. Cylinder Head Cover
5. Rocker Arm Shaft Assembly
·Loosen bolts and nuts of rocker arm shaft
·Bracket by turns and removal rocker
·Shaft asm.
6. 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)

6A2 Ð 22 4JG2-NA/4JG2-TURBO ENGINE
CAUTION
·Put removed valve springs in the order of cylinder
number.
7. Valve Stem Oil Seal
·Removal oil seal by pliers.
CAUTION
·Removed oil controller should not be reused.
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)
INSTALLATION
7. Valve Stem Oil Seal
·Install new oil seal to valve guide.
·Guide using special tool.
Special tool: 5-8840-2033-0
6. Valve Spring
·Attach the valve spring to the upper spring seat.
5. Rocker Arm Shaft Assembly
·Install rocker arm shaft with a larger oil hole (¿4)
to the front of engine.
·Align fixing bolt with not of rocker arm shaft and
tighten fixing bolt to the specified torque.
54 (5.5/40)
N·m(Kg·m/lb·ft)
4. Cylinder Head Cover
·Install cylinder head cover and tighten bolt to the
specified torque.
13 (1.3/113)
N·m(Kg·m/lb·in)