ISUZU TROOPER 1998 Service Repair Manual

ENGINE MECHANICAL 6A Ð 21
REASSEMBLY
7. Rocker Arm Shaft
¥ Apply a light coat of engine oil to the rocker arm
shafts.
¥ Position the rocker arm shaft with the large oil
hole (4
f) facing the front of the engine.
¥ Install the rocker shaft together with the rocker
arm, the rocker arm shaft bracket, and the spring.
6. Rocker Arm Shaft Spring
5. Rocker Arm
4. Rocker Arm Shaft Bracket
3. Rocker Arm
2. Rocker Arm Shaft Snap Ring
1. Rocker Arm Shaft Assembly
¥ Install the rocker arm shaft assembly in cylinder
head.
¥ Tighten the rocker arm shaft fixing bolts to the
specified torque.
OIL PUMP

6A Ð 22 ENGINE MECHANICAL
DISASSEMBLY
1. Flywheel
2. Cylinder Block Rear Plate
3. Crankcase Assembly
¥ Refer to section 6A2 ÒCrankcaseÓ.
4. Oil Pump Assembly
5. Oil Pipe
6. Strainer Assembly
7. Pump Cover
8. Driven Gear
9. Pinion Gear
10. Relief Valve
11. Drive Shaft
12. Oil Pump Body
INSPECTION AND REPAIR
Make the necessary adjustments, repairs, and part placements if excessive wear or damage is discovered
during inspection.
Body and gears
The pump assembly must be replaced if one or more of
the conditions below is discovered during inspection.
¥ Badly worn or damaged driven gear guide.
¥ Badly worn or damaged gear teeth.
Gear Teeth and Body Inner Wall Clearance
¥ Use a feeler gauge to measure the clearance between
the gear teeth and the body inner wall.
¥ If the clearance between the gear teeth and the body
inner wall exceeds the specified limit, either the gear
or the body must be replaced.
Standard Limit
mm(in)
0.14 (0.0055) Gear Teeth and Body
Internal Wall Clearance
0.20 (0.0079)

ENGINE MECHANICAL 6A Ð 23
Drive Shaft and Oil Pump Body Clearance
¥ Use a micrometer to measure the drive shaft outside
diameter.
¥ Use an inside dial indicator to measure the pump
body inside diameter.
¥ If the clearance between the drive shaft and the oil
pump body exceeds the specified limit, the oil pump
assembly must be replaced.
Gear and Body Clearance
¥ Use a feeler gauge to measure the clearance between
the body and the gear.
¥ If the clearance between the gear and the body
exceeds the specified limit, the body must be re-
placed.
Standard Limit
mm(in)
0.06 (0.0024) Gear and Body Clearance
0.15 (0.0059)
Standard Limit
mm(in)
0.04 (0.0016) Drive Shaft and Oil Pump Body Clearance
0.20 (0.0079)
REASSEMBLY
12. Oil Pump Body
11. Drive Shaft
10. Relief Valve
9. Pinion Gear
8. Driven Gear
7. Pump Cover
6. Strainer Assembly
¥ Install the strainer assembly and tighten the
strainer assembly fixing bolts.
5. Oil Pipe
16 (1.6/12)
N·m(kg·m/lb·ft)

6A Ð 24 ENGINE MECHANICAL
4. Oil Pump Assembly
¥ Apply molybdenum mixed engine oil to drive
gear of camshaft and driven gear of oil pump.
¥ Tighten the oil pump fixing bolt to the specified
torque
3. Crankcase Assembly
¥ Refer to Section 6A2 ÒCrankcaseÓ.
2. Cylinder Block Rear Plate
¥ Align the rear plate with the cylinder body knock
pins. Tighten the rear plate to the specified
torque.
1. Flywheel
¥ Refer to Section 6A2 ÒCrankshaft and Main
BearingÓ.
19 (1.9/14)
N·m(kg·m/lb·ft)
82 (8.4/61)
N·m(kg·m/lb·ft)

ENGINE MECHANICAL 6A Ð 25
CRANKSHAFT
DISASSEMBLY
1. Cylinder Head
·Refer to ÒCylinder headÓ in Section 6A2.
2. Camshaft Timing Gear
·Refer to ÒCamshaftÓ in Section 6A2.
3. Crankshaft Timing Gear
4. Crankshaft Front Oil Seal
5. Timing Gear Case
6. Flywheel
7. Cylinder Block Rear Plate

6A Ð 26 ENGINE MECHANICAL
8. Crankshaft Rear Oil Seal
·With the oil seal pushed in deep, install the special
tool as shown in the illustration and remove the oil
seal.
Oil Seal Remover : 5-8840-2362-0
9. Crankcase Assembly
·Refer to ÒCrankcaseÓ in Section 6A2.
10. Oil Pump Assembly
11. Piston Cooling Oil Pipe
12. Piston and Connecting Rod Assembly
13. Main Bearing Cap
14. Crankshaft
INSPECTION AND REPAIR
Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered
during inspection.
1. Crankshaft
Thrust clearance
Set the dial indicator as shown in the illustration and
measure the crankshaft thrust clearance.
If the thrust clearance exceeds the specified limit, re-
place the thrust bearing as a set.
Standard Limit
mm(in)
0.10 (0.0039) 0.30 (0.0118)
167 (17/123)N·m(kg·m/lb·ft)
2. Main bearing clearance
1) Remove the main bearing caps in the sequence
shown in the illustration
Arrange the removed main bearing caps in the
cylinder number order.
2) Remove the crankshaft. Remove the main
bearings.
3) Clean the upper and lower bearings as well as the
crankshaft main journal.
4) Check the bearings for damage or excessive wear.
The bearings must be replaced as a set if damage
or excessive wear is discovered during inspection.
5) Set the upper bearings and the thrust washers to
their original positions. Carefully install the
crankshaft.
6) Set the lower bearings to the bearing cap original
position.
7) Apply plastigage to the crankshaft journal unit as
shown in the illustration.
8) Install the main bearing caps. Apply engine oil to
the bolt threads and the seats. Tighten the bolts
to the specified torque.

ENGINE MECHANICAL 6A Ð 27
NOTE:
Do not allow the crankshaft to rotate.
9) Remove the main bearing caps.
10) Measure the plastigage width and determine the
oil clearance. If the oil clearance exceeds the
specified limit, replace the main bearings as a set
and/or replace the crankshaft.
11) Clean the plastigage from the bearings and the
crankshaft.
Remove the crankshaft and the bearings.
3. Run-out
1) Carefully set the crankshaft on the V-blocks.
Slowly rotate the crankshaft and measure the
runout. If the crankshaft runout exceeds the
specified limit, the crankshaft must be replaced.
Measure the diameter and the uneven wear of
main journal and crank pin.
If the crankshaft wear exceeds the specified limit,
crankshaft must be replaced.
Standard Limit
mm(in.)
0.031 – 0.063
(0.0012 – 0.0025)0.11 (0.0043)
Standard Limit
mm(in)
0.05 (0.0020)
or less0.08 (0.0031) Run-Out
Standard Limitmm(in)
Main journal
diameter69.91
(2.7524)
69.917-69.932
(2.7526-2.7532)
Crank pin
diameter52.90
(2.0843) 52.915-52.930
(2.0833-2.0839)
Uneven
wear limit
0.05
(0.0020)
or less
0.08
(0.0031)

6A Ð 28 ENGINE MECHANICAL
Crankshaft inspection
Inspect the surface of the crankshaft journals and crank
pins for excessive wear and damage.
Inspect the oil seal fitting surfaces for excessive wear and
damage.
Inspect the oil ports for obstructions.
Crankshaft tufftriding inspection
The portion to be tested must be held horizontally so as
not to let the test solution flow.
Test liquid should not be applied to the area around the
oil port.
The sliding surface of the pin or journal.
Approximately 10mm
NOTE:
To increase crankshaft strength,Tufftride Method (Soft
nitriding) has been applied. Because of this, it is not
possible to regrind the crankshaft surfaces.
1. Use an organic cleaner to thoroughly clean the crank-
shaft. There must be no traces of oil the surfaces to be
inspected.
2. Prepare a 5 - 10% solution of ammonium cupric chloride
(dissolved in distilled water).
3. Use a syringe to apply the solution to the surface to be
inspected.
Hold the surface to be inspected perfectly horizontal to
prevent the solution from running.
NOTE:
Do not allow the solution to come in contact with the oil
ports and their surrounding area.
Testing
1. Wait for thirty to forty seconds.
If there is no discoloration after thirty or forty seconds,
the crankshaft is usable.
If discoloration appears (the surface being tested will
become the color copper), the crankshaft must be re-
placed.
2. Steam clean the crankshaft surface immediately after
completing the test.
NOTE:
The ammonium cupric chloride solution is highly corrosive.
Because of this, it is imperative that the surfaces being
tested be cleaned immediately after completing the test.

ENGINE MECHANICAL 6A Ð 29
Crankshaft Bearing Selection
When installing new crankshaft bearings or replacing old
bearings, refer to the selection table below.
Select and install the new crankshaft bearings, paying close
attention to the cylinder body journal hole 1 diameter size
mark and the crankshaft journal 2 diameter size mark.
Crankshaft Bearing Housing Grade Mark Position
Crankshaft bearing housing grade marks 1 or 2 are
stamped on the rear right hand side of the cylinder body.
Example:
Crankshaft Journal Grade Mark Position
The crankshaft journal grade marks (1 or Ð) are stamped on
each crankshaft journal web.
The crankshaft journal and bearing clearance must be the
same for each position after installation of the crankshaft
and the crankshaft bearings.
Note:
The crankshaft journal mark No. 4 is stamped on crankshaft
No. 4 journal web front side or rear side.
NOTE:
Although all upper journal bearings (cylinder body side)
have oil grooves and holes, all lower bearings (bearing
cap side) have no groove and hole.
Play close attention to the distinction during the installa-
tion procedure.
Main Bearing
Bore Diameter mm(in.)Crankshaft
Main Journal Diameter mm(in.)
Size Mark Inside DiameterGrade Mark Outside Diameter
Crankshaft
Bearing
Grade Mark
Oil Clearance
mm (in.)
1 or - 69.927 ~ 69.932
(2.7530 ~ 2.7532)
2 or - -69.922 ~ 69.927
(2.7528 ~ 2.7530)
3 or - - -69.917 ~ 69.922
(2.7526 ~ 2.7528)
1 or -69.927 ~ 69.932
(2.7530 ~ 2.7532)
2 or - - 69.922 ~ 69.927
(2.7528 ~ 2.7530)
3 or - - -69.917 ~ 69.922
(2.7526 ~ 2.7528)Black
Blue
Green
Black 73.987 ~ 74.000
(2.9129 ~ 2.9134)
73.975 ~ 73.987
(2.9124 ~ 2.9129) 1
20.035 ~ 0.061
(0.0014 ~ 0.0024)
0.032 ~ 0.058
(0.0013 ~ 0.0023)
0.037 ~ 0.063
(0.0015 ~ 0.0025)
0.031 ~ 0.056
(0.0012 ~ 0.0022)
0.036 ~ 0.048
(0.0014 ~ 0.0019)
0.033 ~ 0.058
(0.0013 ~ 0.0023)
No. 1 Bearing
HousingNo. 2 Bearing
HousingNo. 3 Bearing
HousingNo. 4 Bearing
HousingNo. 5 Bearing
Housing
12112

6A Ð 30 ENGINE MECHANICAL
REASSEMBLY
14. 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.
·Apply engine oil to the thrust washer.
·Assemble the thrust washer to the No. 3 bearing
journal. The oil grooves must face the crankshaft.
13. Main Bearing Cap
·Apply the recommended liquid gasket or its equiva-
lent to the No. 5 crankshaft bearing cap 1 as shown
in the illustration.
·Install the arch gasket 2 to the No. 5 bearing cap.
Use your fingers to push the arch gasket into the
bearing cap groove.
NOTE
Take care not to scratch the arch gasket outer surface.
·Apply the recommended liquid gasket or its equiva-
lent to the No. 5 crankshaft bearing cap cylinder
body fitting surfaces at points 3 and 4 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.