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Isuzu Trooper (1998-2002 year). Manual - part 571

6A – 92 ENGINE MECHANICAL

CYLINDER BLOCK

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Legend

(1)

Cylinder Head

(2)

Cylinder Head Gasket

(3)

Flywheel

(4)

Cylinder Block Rear Plate (A/T)
Flywheel Housing (M/T)

(5)

Crankshaft Rear Oil Seal

(6)

Retainer

(7)

Timing Gear Case Cover

(8)

Crankshaft Front Oil Seal

(9)

Timing Gear Case

(10)

Gasket

(11)

Balance Shaft

(12)

Crank Case

(13)

Piston Cooling Oil Pipe

(14)

Main Bearing Cap

(15)

Crankshaft

(16)

Crankshaft Timing Gear

(17)

Piston and Connecting Rod Assembly

(18)

Cylinder Block

ENGINE MECHANICAL 6A – 93

DISASSEMBLY

1. Cylinder Head Assembly

Refer to “Cylinder Head” in this manual.

2. Cylinder Head Gasket.
3. Flywheel
4. Cylinder Block Rear Plate (A/T), or Flywheel

housing (M/T).

5. Crankshaft Rear Oil Seal.

Install the special tool as shown in the illustration
and remove the oil seal.
Oil Seal Remover: 5-8840-2360-0

6. Retainer
7. Timing Gear Case Cover
8. Crankshaft Front Oil Seal

1) Use a plastic hammer and a screwdriver to tap

around the oil seal to free it from the gear case
cover.

9. Timing Gears

Refer to “Timing Gear” in this manual.

10. Timing gear case
11. Gasket
12. Balance shaft (right)
13. Crank case assembly
14. Piston cooling oil pipe
15. Piston assembly
16. Main bearing cap
17. Crankshaft assembly
18. Cylinder block side cover right and left
19. Cylinder block

INSPECTION AND REPAIR

Make the necessary adjustments, repairs, and part
replacements if excessive wear or damage is
discovered during inspection.

1. Remove the cylinder head 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 liquid gasket, which was used

when assembled, from gear case, rear oil seal
retainer and crank case.

3. Wipe the cylinder block clean and visually check it.
4. Use a straight edge and a feeler gauge to measure

the four sides and the two diagonals of the cylinder
block upper face.
If the measured values exceed the limit, the cylinder
block must be replaced.

Limit: 0.20 mm (0.0079 in)

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6A – 94 ENGINE MECHANICAL

Cylinder Bore Measurement

1. Use a cylinder gauge to measure the cylinder bore

measuring direction for thrust and radial at
measuring points.

Legend

Measuring Point 1; 20 mm

2; 90 mm
3; 160 mm

2. Select the right piston grade by the averaged

cylinder bore measurement (maximum and
minimum value eliminated).

Cylinder bore diameter

mm(in)

Grade mark

Standard

95.421 – 95.430 (3.7567 – 3.7571)

95.431 – 95.440 (3.7571 – 3.7575)

95.441 – 95.450 (3.7575 – 3.7579)

3. If measured values exceed the limit, replace or

adjust the cylinder block honing or boring.

Limit 95.950 mm (3.7776 in)

4. Boring of the cylinder bore is allowed until it is

0.5 mm (0.0197 in) diameter and oversized piston
is available as a service part.

Boring Cylinder Block

1. Use an oversized piston on the basis of above

mentioned cylinder using the largest inside
diameter.

2. Measure the piston outside diameter at right angles

with piston pin at a piston grade measuring point
69.75 mm (2.7461 in) from piston top surface and
calculate a inside diameter for cylinder boring.

3. Calculation of cylinder bore boring.

D + C – H (mm)

D; Outside diameter piston (mm)
C; Clearance between Cylinder bore and piston
0.092 – 0.110 mm (0.0036 – 0.0043 in)
H; Honing allowance
Less than 0.03 mm (0.0012 in)

The oversize pistons are available three grades.

4. Honing the cylinder bore after boring.
5. Measure cylinder bore after honing.

Difference between each cylinder bore

Less than 0.02 mm (0.0008 in)

Cylinder bore and piston grade (After boring)

mm(in)

Grade

Oversize Piston

Bore

Mark

Outside Diameter

Diameter

95.820 – 95.829

95.921 – 95.930

(3.7724 – 3.7728)

(3.7764 – 3.7768)

95.830 – 95.839

95.931 – 95.940

(3.7728 – 3.7732)

(3.7768 – 3.7772)

95.840 – 95.849

95.941 – 95.950

(3.7732 – 3.7736 )

(3.7772 – 3.7776)

REASSEMBLY

1. Cylinder Block
2. Piston Cooling Oil Pipe

1) Fix the cooling 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.
If oil jet pipe is forcibly assembled, the end of oil
jet may bend. It could make it impossible to
supply oil to the piston cooling hole, sometimes
causing piston seizure.
Sufficient care should be taken to pipe assembly
work.

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ENGINE MECHANICAL 6A – 95

Oil pipe fixing bolts

M8: 20 N·m (2.0 kg·m/14 lb ft)
M6: 8 N·m (0.8 kg·m/69 lb in)

Relief valve fixing bolts : 30 N·m (3.1 kg·m/22 lb ft)

CAUTION: After installing the piston assembly,
check and see that there is appropriate clearance
between pistons and oil jet pipes by rotating
crankshaft slowly.

3. Crankshaft

1) Install the main bearings to the cylinder body

and the main bearing caps.

2) Be sure that they are positioned correctly.
3) Apply new engine oil to the upper and lower

main bearing faces.

4) Carefully mount the crankshaft.

5) Apply engine oil to the thrust washer.
6) Assemble the thrust washer to the No. 3

bearing journal. The oil grooves must face the
crankshaft.

4. Main Bearing Cap Assembly

1) Install the main bearing caps with the main

bearing cap head arrow mark facing the front of
the engine.

2) Apply engine oil to the main bearing cap bolts.
3) Tighten the main bearing cap bolts to the

specified torque a little at a time in the sequence
shown in the illustration.

Torque: 167 N·m (17.0 kg·m/123 lb ft)

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Content .. 569 570 571 572 ..