engine ISUZU TROOPER 1998 Service Repair Manual

6A Ð 16 ENGINE MECHANICAL
4. Camshaft Run-Out
¥ Mount the camshaft on V-blocks.
¥ Measure the run-out with a dial indicator.
If the measured value exceeds the specified limit,
the camshaft must be replaced.
5. Camshaft and Camshaft Bearing Clearance
¥ Use an inside dial indicator to measure the
camshaft bearing inside diameter.
Standard Limit
mm(in)
0.02 (0.0008) or less 0.10 (0.0039) Run-Out
¥ If the clearance between the camshaft bearing
inside diameter and the journal exceeds the
specified limit, the camshaft bearing must be
replaced.
Camshaft Bearing Replacement
Camshaft Bearing Removal
1. Remove the cylinder body plug plate.
2. Use the bearing replacer to remove the camshaft
bearing.
Bearing Replacer: 5-8840-2038-0
Camshaft Bearing Installation
1. Align the bearing oil holes with the cylinder body oil
holes.
2. Use the replacer to install the camshaft bearing.
Bearing Replacer: 5-8840-2038-0
Standard Limit
mm(in)
50.00 – 50.03
(1.9685 – 1.9697)50.08 (1.9716) Camshaft Bearing Inside Diameter
Standard Limit
mm(in)
0.025 – 0.085
(0.0010 – 0.0033)0.12 (0.0047) Camshaft Bearing Clearance

ENGINE MECHANICAL 6A Ð 17
REASSEMBLY
9. Tappet
1) Apply a coat of engine oil to the tappet and the
cylinder body tappet insert holes.
2) Locate the position mark applied at disassembly (if
the tappet is to be reused).
NOTE:
The tappet must be installed before the camshaft.
TAPPET
Visually inspect the tappet camshaft contact surfaces for
pitting, cracking, and other abnormal conditions. The
tappet must be replaced if any of these conditions are
present.
Refer to the illustration at the left.
1Normal contact
2Cracking
3Pitting
4Irregular contact
5Irregular contact
NOTE:
The tappet surfaces are spherical. Do not attempt to
grind them with an oil stone or similar tool in an effort to
repair the tappet. If the tappet is damaged, it must be
replaced.
Tappet Outside Diameter
1. Measure the tappet outside diameter with a microme-
ter. If the measured value is less than the specified
limit, the tappet must be replaced.
2. Measure the inside diameter tappet on the cylinder
block and calculate the clearance.
If the clearance exceeds the limit, replace tappet or/
and cylinder block.
Standard Limit
mm(in)
12.97 – 12.99
(0.5106 – 0.5114)12.95 (0.5098) Tappet Outside Diameter
Standard Limit
mm(in)
0.03 (0.0012) 0.10 (0.0039) Clearance Between Tappet and Cylinder Body

6A Ð 18 ENGINE MECHANICAL
8. Camshaft
1) Apply a coat of engine oil to the camshaft and the
camshaft bearings.
Install the camshaft to the cylinder body.
Take care not to damage the camshaft bearings.
7. Camshaft Thrust Plate
Install the thrust plate to the cylinder body and tighten the
thrust plate bolts to specified torque.
6. Camshaft Timing Gear
1) Install the camshaft timing gear to the camshaft.
The timing gear mark ("Y - Y") must be facing out-
ward.
2) Tighten the timing gear to the specified torque.
5. Oil Pump Assembly
¥ Refer to Section 6A2 ÒOil Pump InstallationÓ.
4. Crankcase Assembly
¥ Refer to Section 6A2 ÒCrankcaseÓ.
3. Cylinder Block Rear Plate
¥ Tighten cylinder block rear plate fixing bolts to the
specified torque.
18 (1.8/13)N·m(Kg·m/lb·ft)
64 (6.5/47)N·m(Kg·m/lb·ft)
82 (8.4/61)N·m(kg·m/lb·ft)
2. Flywheel
¥ Refer to Section 6A2 ÒCrankshaft InstallationÓ.
1. Cylinder Head Assembly
¥ Refer to Section 6A2 ÒCylinder Head InstallationÓ.

ENGINE MECHANICAL 6A Ð 19
ROCKER ARM ASSEMBLY
DISASSEMBLY
1. Rocker Arm Shaft Assembly
2. Rocker Arm Shaft Snap Ring
3. Rocker Arm
4. Rocker Arm Shaft Bracket
5. Rocker Arm
6. Rocker Arm Shaft Spring
7. Rocker Arm Shaft
INSPECTION AND REPAIR
Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered
during inspection.
Use a micrometer to measure the rocker shaft outside
diameter at the point where the rocker arm moves on the
rocker shaft.
Replace the rocker shaft if the diameter exceeds the
specified limit.
Standard Limit
mm(in) Rocker Arm Shaft Outside Diameter
18.98 – 19.00
(0.7472 – 0.7480)18.9 (0.7441)

6A Ð 20 ENGINE MECHANICAL
Oil Clearance
1. Use either a vernier caliper or a dial indicator to
measure the rocker arm inside diameter.
2. Measure the rocker arm shaft outside diameter.
If the measured value exceeds the specified limit,
replace either the rocker arm or the rocker arm shaft.
3. Check that the rocker arm oil port is free of obstruc-
tions.
If necessary, use compressed air to clean the rocker
arm oil port.
Rocker Arm Correction
Inspection the rocker arm valve stem contact surface for
step wear 1 and scoring 2.
If the contact surfaces have light step wear or scoring,
they may be honed with an oil stone.
If the step wear or scoring is severe, the rocker arm must
be replaced.
Rocker Arm Shaft Run-Out
1. Place the rocker arm shaft on a V-block.
2. Use a dial indicator to measure the rocker arm shaft
central portion run-out.
If the run-out is very slight, correct the rocker arm
shaft run-out with a bench press. The rocker arm
must be at cold condition.
If the measured rocker arm shaft run-out exceeds the
specified limit, the rocker arm shaft must be replaced.
0.3 (0.0118)
mm(in) Rocker Arm Shaft Run-Out
Limit
Standard Limit
mm(in)
19.01 – 19.03
(0.7484 – 0.7492)19.100 (0.7520) Rocker Arm Inside Diameter
Standard Limit
mm(in)
0.01 – 0.05
(0.0004 – 0.0019)0.20 (0.0079) Clearance Between Rocker Arm and
Rocker Arm Shaft

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