ISUZU TROOPER 1998 Service Repair Manual

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)

6A2 Ð 4 4JG2-NA/4JG2-TURBO ENGINE
118 (12.0/87)N·m(kg·m/lb·ft)
ENGINE MOUNT (LH)
REMOVAL
Preparation:
·Disconnect battery ground cable
·Support engine
·Support vehicle
1. Front Tire
2. Dust Cover
3. Engine Mount
·Remove fixing bolts from cylinder body and
chassis frame.
INSTALLATION
3. Engine Mount
·Tighten the fixing bolts to the specified torque
2. Dust Cover
1. Front Tire
·Tighten the fire fixing nuts to specified torque
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
41 (4.2/30)
N·m(kg·m/lb·ft) Chassis frame side

4JG2-NA/4JG2-TURBO ENGINE 6A2 Ð 5
INTERCOOLER (4JG2-T only)
REMOVAL
Preparation:
·Disconnect battery ground cable
1. Air Cleaner Cover & Air Duct
·Remove bolts from intercooler.
2. Vacuum Hose
3. Intercooler Assembly
·Disconnect outlet hose from intake manifold.
·Remove bolts from engine side brakets.
INSTALLATION
3. Intercooler
·Connect outlet hose to intake manifold.
·Install intercooler and tighten fixing bolts to the
specified torque.
19 (2.0/14)N·m (Kg·m/lb·ft)
2. Vacuum Hose
1. Air Cleaner Cover & Air Duct

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

6A2 Ð 8 4JG2-NA/4JG2-TURBO ENGINE
INLET MANIFOLD
REMOVAL
1. Intercooler (4JG2-T only)
2. Oil Level Gauge Tube (4JG2-T only)
3. Heater and Oil Cooler Pipe Fixing Bolts.
·Remove fixing bolts from inlet manifold.
4. Injection Pipes
5. Inlet Manifold
INSTALLATION
5. Inlet Manifold
·Tighten the fixing bolts and nuts to the specified
19 (1.9/14)
N·m(Kg·m/lb·ft) Bolt
24(2.4/18)N·m(Kg·m/lb·ft)
Nut