ISUZU TROOPER 1998 Service Repair Manual

6A±55
ENGINE MECHANICAL
014RW024
Legend
(1) Right Bank
(2) Left Bank(3) Alignment Mark on Camshaft Drive Gear
(4) Alignment Mark on Camshaft
(5) Alignment Mark on Retainer
3. Tighten twenty bolts in numerical order on one
side bank as shown in the illustration.
Torque: 10 N´m (1.0 Kg´m/89 lb in)
014RW031
5. Tighten bolt for camshaft drive gear assembly pulley
to the specified torque.
Torque: 98 N´m (10.0 Kg´m/72 lb ft)

6A±56
ENGINE MECHANICAL
Valve Spring, Oil Controller, Valve, Valve Guide
Valve Spring, Oil Controller, Valve, Valve Guide and Associated Parts
014RW039
Legend
(1) Camshaft Bracket Fixing Bolts
(2) Camshaft Assembly Inlet
(3) Camshaft Assembly Exhaust
(4) Shim
(5) Tappet
(6) Split Collar(7) Spring Upper Seat
(8) Valve Spring
(9) Oil Controller
(10) Spring Lower Seat
(11) Valve Guide
(12) Valve
Disassembly
1. Remove camshaft bracket fixing bolts (1).
2. Remove camshaft assembly (intake).3. Remove camshaft assembly (Exhaust side).
4. Remove shim (4) and tappet (5).

6A±57
ENGINE MECHANICAL
5. Use 5±8840±2446±0 valve spring compressor and
5±8840±2547±0 valve spring compressor adapter to
remove split collar.
014RW042
6. Remove valve spring.
7. Remove valve.
8. Remove oil controller and spring lower seat.
9. Remove the valve guide using the 5±8840±2442±0
valve guide replacer.
Inspection and Repair
Valve Spring
CAUTION: Visually inspect the valve springs and
replace them if damage or abnormal wear is evident.
1. Measure the free height of the springs. The springs
must be replaced if the free height is below the
specified limit.
Standard : 44.6 mm (1.7559 in)
Limit : 43.6 mm (1.7165 in)
014RS004
2. Measure the valve spring squareness with a steel
square and replace the valve springs if the measured
value exceeds the specified limit.
Limit : 2 mm (0.0787 in)
014RS005
3. Using a spring tester to compress the springs to the
installed height, measure the compressed spring
tension, and replace the springs if the measured
tension is below the specified limit.
At installed height: 35.0 mm (1.38 in)
Standard: 196 N (44 lb)
Limit: Less than 181 N (41 lb)
014RS006
Valve Guide
CAUTION: Take care not to damage the valve seat
contact surface, when removing carbon adhering to
the valve head. Carefully inspect the valve stem for
scratchs or abnormal wear. If these conditions are
present, the valve and the valve guide must be
replaced as a set.

6A±58
ENGINE MECHANICAL
1. Measure the valve stem diameter with a micrometer.
If the valve stem diameter is less than the specified
limit, the valve and the valve guide must be replaced
as a set.
Diameter of Valve Stem
Intake
Standard : 5.977 mm±5.959 mm
(0.2353 in±0.2346 in)
Limit : 5.90 mm (0.2323 in)
Exhaust
Standard : 5.952 mm±5.970 mm
(0.2343 in±0.2350 in)
Limit : 5.90 mm (0.2323 in)
014RS007
2. Measure the inside diameter of the valve guide with a
micrometer. Subtract the measured outer diameter of
the valve stem from the measured inner diameter of
the valve guide. If the value exceeds the specified
limit, the valve and the valve guide must be replaced
as a set.
Inside Diameter of the Vale Guide
Inlet clearance
Standard : 0.023 mm±0.056 mm
(0.0009 in±0.0002 in)
Limit : 0.20 mm (0.00787 in)
Exhaust clearance
Standard : 0.030 mm±0.063 mm
(0.0012 in±0.0025 in)
Limit : 0.20 mm (0.00787 in)
Valve Guide Replacement
1. Using Valve guide replacer: 5±8840±2442±0, drive
out the valve guide from the combustion chamber
side.
014RS008
2. Apply engine oil to the outside of the valve guide.
Using valve guide replacer 5±8840±2442±0, drive in
a new valve guide from the camshaft side, and check
the valve guide height.
Valve guide upper end height: 13.0 mm (0.5118
in)
(Measured from the cylinder head upper face)
014RW046
3. Check the clearance. If the clearance is less than the
specified value, ream the inside diameter of valve
guide. Using a sharp 6 mm reamer, ream the valve
guide to obtain the specified clearance.
Valve Seat
1. Measure the protrusion of the valve stem when a new
valve is installed in the cylinder head. If the protrusion
of the valve stem exceeds the limit, replace the valve
seat insert or the cylinder head assembly.
Protrusion of valve stem
Intake
Standard: 39.32 mm (1.5480 in)

6A±59
ENGINE MECHANICAL
Limit: 39.47 mm (1.5539 in)
Exhaust
Standard: 39.30 mm (1.5472 in)
Limit: 39.45 mm (1.5531 in)
014RW047
2. Measure the valve seat contact width. Make the
necessary corrections if the seat contact surface is
damaged or rough or if the contact width wear
exceeds the limit.
Valve seat contact width
Standard: 1.1 mm (0.0433 in)
Limit: 1.7 mm (0.0669 in)
014RS011
Contact Surface Angle on Valve Seat on
Valve
1. Measure contact surface angle on valve seat.2. If the measured value exceeds the limit, replace
valve, valve guide and valve seat as a set.
Valve contact surface angle: 45

014RS012
Valve Seat Insert Correction
1. Remove the carbon from the valve seat insert
surface.
2. Use a valve cutter to minimize scratches and other
rough areas. This will bring the contact width back to
the standard value. Remove only the scratches and
rough areas. Do not cut away too much. Take care not
to cut away unblemished areas of the valve seat
surface.
Valve seat angle degree: 90

014RW059
3. Apply abrasive compound to the valve seat insert
surface.
4. Insert the valve into the valve guide.
5. Turn the valve while lapping it to fit the valve seat
insert.

6A±60
ENGINE MECHANICAL
6. Check that the valve contact width is correct.
7. Check that the valve seat insert surface is in contact
with the entire circumference of the valve.
014RS014
Valve Seat Insert Replacement
1. Arc weld the rod at several points. Be careful not to
damage the aluminum section.
2. Allow the rod to cool for a few minutes. This will cause
the valve seat to shrink.
3. Strike the rod and pull it out.
014RS015
4. Carefully clean the valve seat press±fit section on the
cylinder head side.
5. Heat the press±fit section with steam or some other
means to cause expansion. Cool the valve seat with
dry ice or some other means.
6. Insert the press±fit section into the valve seat
horizontally.
Standard fitting interference: 0.14 mm±0.09 mm
(0.0055 in±0.0035 in)7. After insertion, use a seat grinder to grind finish the
seating face. Carefully note the seating angle, the
contact width, and the depression.
8. Lap the valve and the seat.
Reassembly
1. Install valve guide (1) to cylinder head. Apply engine
oil to the outside of the valve guide. Using valve guide
replacer 5±8840±2442±0, drive in a new valve guide
from the camshaft side.
2. Install oil controller (3) and spring lower seat (2).
Using oil controller replacer 5±8840±0623±0, drive in
a new oil controller.
014RW058
3. Install valve to valve guide. Before install valve guide
apply engine oil to the outside of the valve stem.
4. Install valve spring to cylinder head. Attach the valve
spring to the lower spring seat. The painted area of
the valve spring should be facing downward.
014RS020

6A±61
ENGINE MECHANICAL
5. Install lower valve spring seat, valve spring and upper
valve spring seat then put split collars on the upper
spring seat, using the 5±8840±2446±0 valve spring
compressor and 5±8840±2547±0 valve spring
compressor adapter to install the split collars.
014RW042
6. Install tappet with shim.
7. Install camshaft assembly.

Refer to installation procedure for Camshaft in this
manual.
Valve Clearance Adjustments
NOTE: To adjust valve clearance, apply engine oil to the
cam as well as to the adjusting shim (2) with the cylinder
head built on the cylinder block, give a few turns to the
camshaft by means of timing pulley tightening bolt, and
measure valve clearance when the nose of cam is just
opposite to maximum cam lift (1) as shown in illistration
below.
014RW081
Legend
(1) Cam
(2) Shim
(3) Tappet
Valve Clearance Standard Value (cold)
Intake: 0.23 mm±0.33 mm
(0.0091 in±0.0130 in)
Exhaust: 0.25 mm±0.35 mm
(0.0098 in±0.0138 in)
Selection of Adjusting Shim
Shim to be selected = (Thickness of removed shim) +
(Valve clearance measurement ± Standard valve)
Based on the above formula, the best suited shim should
be selected from 41 sorts of shim (differently thick at
0.02mm (0.0008 in) intervals from 2.40mm (0.0945 in)
through 3.2mm (0.1260 in) thick). Install the shim and
check valve clearance.

6A±62
ENGINE MECHANICAL
Replacement of Shim
Let the cam push down the edge of tappet by using
5±8840±2444±0 valve clearance adjusting tool and push
out the shim with a flat blade screw driver as shown in
illustrations below.
014RW082
014RW083
014RW084

6A±63
ENGINE MECHANICAL
Camshaft
Camshaft and Associated Parts
014RW040
Legend
(1) Camshaft Bracket Fixing Bolt
(2) Camshaft Bracket
(3) Camshaft Assembly Intake
(4) Camshaft Assembly Exhaust
(5) Pulley Fixing Bolt(6) Camshaft Drive Gear Pulley
(7) Retainer Fixing Bolt
(8) Retainer
(9) Camshaft Drive Gear
(10) Oil Seal
Disassembly
1. Remove fixing bolt (5) for camshaft drive gear pulley
using the 5±8840±2447±0 universal holder.

6A±64
ENGINE MECHANICAL
014RW060
2. Remove twenty fixing bolts from inlet and exhaust
camshaft bracket on one side bank, then camshaft
brackets (2).
014RW027
3. Remove camshaft assembly (3), (4).
4. Remove three fixing bolts (7) from camshaft drive
gear retainer (8), then camshaft drive gear assembly.
Inspection and Repair
1. Use a micrometer to measure the cam lobe height
and uneven wear. Replace the camshaft if either the
lobe height or the uneven wear exceeds the specified
limit.
Lobe height : 44.709 mm (1.7602 in)
Uneven wear : 0.05 mm (0.0020 in)
014RW043
2. Use a micrometer to measure the diameter and the
uneven wear of the camshaft journals.
Replace the camshaft if the diameter or the uneven
wear exceeds the specified limit.
Journal Diameter
Standard : 25.972 mm±25.993 mm
(1.0225 in±1.0233 in)
Limit : 25.8 mm (1.0157 in)
Uneven wear : 0.05 mm (0.0020 in)
014RS023
3. Place the camshaft on V±blocks.
Slowly rotate the camshaft and measure the runout
with a dial indicator.
Replace the camshaft if the runout exceeds the
specified limit.