1998 ISUZU TROOPER check engine

6A Ð 32 ENGINE MECHANICAL
19 (1.9/14)N·m(kg·m/lb·ft)
5. Timing Gear Case
1) Install the timing gear case to the cylinder body.
NOTE:
Take care not to twist the front oil seal.
6. Flywheel
1) Thoroughly clean and remove the oil from the
threads of crankshaft.
2) Mount the flywheel on the crankshaft and then
install the washer.
3) Align the flywheel with the crankshaft dowel pin.
4) Tighten the flywheel bolts to the specified torque
in the numerical order shown in the illustration.
82 (8.4/61)N·m(kg·m/lb·ft)
NOTE:
Take care not to damage the O-rings when tightening the
oil pipe bolts.
9. Crankcase Assembly
·Refer to ÒCrankcaseÓ Section 6A2
8. 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
7. Cylinder Block Rear Plate
Align the rear plate with the cylinder body knock pins.
Tighten the rear plate to the specified torque.
118 (12.0/87)N·m(kg·m/lb·ft)

ENGINE MECHANICAL 6A Ð 35
6. Piston Ring
Remove the piston rings with a piston ring expander.
Arrange the removed piston rings in the cylinder
number order.
7. Piston Pin Snap Ring
·Use a pair of pliers to remove the piston pin snap
rings
8. Piston Pin
NOTE:
Keep the parts removed from each cylinder separate. All
parts must be reinstalled in their original positions.
9. Piston
10. Connecting Rod
INSPECTION AND REPAIR
PISTON AND PISTON RING
Pistons
Carefully clean away all the carbon adhering to the piston
head and the piston ring grooves.
NOTE:
Never use a wire brush to clean the pistons. Damage will
result.
Visually check each piston for cracking, scoring, and other
signs of excessive wear.
If any of the above conditions are present, the piston
must be replaced.
Piston Diameter
1. Measure the piston outside diameter with micrometer
at the piston grading position.
71.00 (2.7974)
mm(in) Piston Grading Position

6A Ð 38 ENGINE MECHANICAL
NOTE:
Align the bushing with the connecting rod oil port.
After installing a new bushing, finish the bushing bore
with a pin hole grinder. 3. Insert the piston pin into the piston and rotate it. If
the pin rotates smoothly with no backlash, the
clearance is normal. If there is backlash or
roughness, measure the clearance. If the clearance
exceeds the specified limit, the piston and the piston
pin must be replaced.
Standard Limit
0.002 ~ 0.015
(0.00008 ~ 0.0006)0.04
(0.0016) Clearancemm (in)
Bushing replacement
Removal: Use a suitable bar and bench press or
hammer.
Installation: Use a suitable bar and bench press.
Connecting rods
1. Check the connecting rod alignment with a
connecting rod aligner.
If either the bend or the twist exceeds the specified
limit, the connecting rod must be replaced.
2. Measure the connecting rod thrust clearance.
Use a feeler gauge to measure the thrust clearance at
the big end of the connecting rod.
If the clearance exceeds the specified limit, the
connecting rod must be replaced.
Standard Limit
0.230 (0.0091) 0.350 (0.0138)mm (in)
Limit
Bend per 100 (3.937)
Twist per 100 (3.937)mm (in)
0.20 (0.0079)
0.15 (0.0059)Standard
0.08 (0.0031) or less
0.05 (0.0020) or less

ENGINE MECHANICAL 6A Ð 39
3. Measure the oil clearance between the connecting
rod and the crankshaft by:
1) Remove the connecting rod cap nuts and the rod
caps.
Arrange the removed rod caps in the cylinder
number order.
2) Clean the rod bearings and the crankshaft pins.
3) Carefully check the rod bearings.
If even one bearing is found to be damaged or
badly worn, the entire bearing assembly must be
replaced as a set. Reinstall the bearings in their
original positions.
Apply plastigage to the crank pin.
4) Reinstall the rod caps to their original positions.
5) Tighten the cap nuts in 2 steps, using angular
tightening method as shown in the following
specifications.
NOTE:
Do not allow the crankshaft to rotate.
N·m (kg·m/lb·ft)
45¡ ~ 60¡ 1st step 2nd step
29 (3.0/22)
6) Remove the rod caps.
7) Measure the width of the plastigage and determine
the oil clearance. If the oil clearance exceeds the
limit, replace the rod bearings as a set.
8) Clean the plastigage from the bearings and the
crankshaft pins.
REASSEMBLY
10. Connecting Rod
9. Piston
8. Piston Pin
·Apply a coat of engine oil to the piston pin and the
piston pin hole.
7. Piston Pin Snap Ring
·Apply a thin coat of engine oil to the piston pin.
Try to insert the piston pin into the piston pin hole
with normal finger pressure.
Weigh each piston and connecting rod assembly.
Select piston and connecting rod combinations so
that the weight variation of the different assemblies
is held within the specified limits.
Variance in weight
after assemblyLess than 3
(0.1058)g (oz)
Standard Limit
0.029 (0.0011) – 0.083 (0.0033) 0.100 (0.0039)
mm (in)
NOTE:
When changing piston/connecting rod combinations, do
not change the piston/piston pin combination.

6A Ð 40 ENGINE MECHANICAL
6. Piston Ring
·Install the piston rings with the piston ring expander.
The compression ring must be set with the 1N, 2N
mark facing up.
·Discrimination mark is painted as shown in the
illustration. ·Attach the piston to the connecting rod with the
piston front mark and the connecting rod ISUZU
mark on the same side.
·Install piston rings in the following sequence.
1) Oil ring
1Expander ring
2) 2nd compression ring
3) 1st compression ring
·The compression ring must be set with the 1N or
2N mark facing up.
·1st compression ring: N
·2nd compression ring: 2N
·After installation, apply engine oil to the entire
circumference of the piston rings.
Check to see that all the rings rotate smoothly.
·Insert the bearings into the connecting rods and
caps.
Apply new engine oil to the bearing faces.
Cap side bearings have no oil hole.
Conn rod side bearingÕs oil hole should be aligned
with oil hole on the conn rod.

ENGINE MECHANICAL 6A Ð 41
5. Piston and Connecting Rod
·Apply engine oil to the cylinder bores, the
connecting rod bearings and the crankshaft pins.
·Check to see that the piston ring end gaps are
correctly positioned.
·Insert the piston/connecting rod assemblies into
each cylinder with the piston ring compressor.
·The front marks must be facing the front of the
engine.
4. Connecting Rod Bearing Cap
·Apply engine oil to screw and seat of bearing cap
bolts and nuts.
·Tighten the cap nuts in 2 steps, using angular
tightening method as shown in the following
specifications.
N·m (kg·m/lb·ft)
45¡ ~ 60¡ 1st step 2nd step
29 (3.0/22)
After tightening the cap nuts, check to see that the
crankshaft rotates smoothly.
3. Oil Pump Assembly
2. Crankcase Assembly
·Refer to ÒCrankcaseÓ in Section 6A2.
1. Cylinder Head Assembly
·Refer to ÒCylinder headÓ in Section 6A2.

6A Ð 44 ENGINE MECHANICAL
INSPECTION REPAIR
Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered
during inspection.
1. Remove the gasket and any other material adhering to
the upper surface of the cylinder block.
Be very careful not to allow any material to accidentally
drop into the cylinder block.
Be very careful not to scratch the cylinder block.
2. Carefully remove the oil pump, Rear Oil Seal retainer,
and oil pan installation surface seal.
3. Wipe the cylinder block clean.
Cylinder Liner Projection Inspection
1. Hold a straight edge 1 along the top edge of the cylinder
liner to be measured.
2. Use a feeler gauge 2 to measure each cylinder liner
projection.
The difference in the cylinder liner projection height
between any two adjacent cylinders must not exceed
0.03 mm (0.0012 in).
0.0 – 0.1 (0.0000 – 0.0039)
mm(in.) Standard
Flatness
1. Remove the cylinder body dowel.
2. Set the cylinder liner remover to the cylinder liner.
3. Check that the remover shaft ankle is firmly gripping the
cylinder liner bottom edge.
4. Slowly turn the remover shaft handle counterclockwise
to pull the cylinder liner free.
Cylinder Liner Remover Ankle: 5-8840-2304-0
Cylinder Liner Remover: 9-8523-1169-0
NOTE:
Take care not to damage the cylinder body upper during the
cylinder liner removal procedure.
5. Use a straight edge 1 and a feeler gauge 2 to measure the
four sides and the two diagonals of the cylinder body
upper face.
If the measured values exceed the limit, the cylinder
body must be replaced.
0.20 (0.0079)
mm(in.) Limit

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)