Isuzu engine 4j series. Manual - part 21

6A – 20

GENERAL ENGINE MECHANICAL

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.

Normal contact

Cracking

Pitting

Irregular 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

micrometer. If the measured value is less than the
specified limit, the tappet must be replaced.

Tappet Outside Diameter

mm (in)

Standard

Limit

12.97 - 12.99

(0.510 - 0.511)

12.95 (0.509)

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.

Tappet and Cylinder Body Clearance

mm (in)

Standard

Limit

0.03 (0.001)

0.10 (0.004)

REASSEMBLY

9. Tappet

1) Apply a coat of engine oil to the tappet 1 and the

cylinder body tappet insert holes 2.

2) Locate the position mark applies at disassembly (if the

tappet is to be reused).

NOTE:

The tappet must be installed before the camshaft.

6A-20-1.tif

6A-20-2.tif

6A-20-3.tif

6A-20-4.tif

GENERAL ENGINE MECHANICAL 6A – 21

8. Camshaft

1) Apply a coat of engine oil to the camshaft and the

camshaft bearings.

2) Install the camshaft to the cylinder body.

Take care not damage the camshaft bearings.

7a. Camshaft Timing Pulley Center (Belt Drive Model)

•

Apply engine oil to the oil seal lip portion of the oil seal
retainer.

•

Apply the recommended liquid gasket or its equivalent
to the retainer.

•

Install the oil seal retainer to the cylinder body.

•

Tighten the retainer bolts to the specified torque.

Oil Seal Retainer Bolt Torque

N∙m (kg∙m/lb∙ft)

19 (1.9/14)

•

Align the camshaft timing pulley center with the
camshaft key.

•

Tighten the timing pulley bolts to the specified torque.

Timing Pulley Bolt Torque

N∙m (kg∙m/lb∙in)

8 (0.8/69)

7. Camshaft Thrust Plate (Gear Drive Model)

Install the thrust plate to the cylinder body and tighten the
thrust plate bolts to specified torque.
Thrust Plate Bolt Torque

N∙m (kg∙m/lb∙ft)

18 (1.8/13)

6a. Camshaft Timing Pulley (Belt Drive Model)

•

Prevent the camshaft from turning when tightening the
timing center bolt.

•

Tighten the timing pulley center bolt to the specified
torque.

Center Bolt Torque

N∙m (kg∙m/lb∙ft)

64 (6.5/47)

6A-21-1.tif

6A-21-2.tif

6A-21-3.tif

6A-21-4.tif

6A-21-5.tif

6A – 22

GENERAL ENGINE MECHANICAL

6. Camshaft Timing Gear (Gear Drive Model)

1) Install the camshaft timing gear to the camshaft.

The timing gear mark (“Y-Y”) must be facing outward.

2) Tighten the timing gear to the specified torque
Timing Gear Bolt Torque

N∙m (kg∙m/lb∙ft)

64 (6.5/47)

5. Oil Pump Assembly

4. Oil Pan Assembly

Above works refer to “OIL PUMP” Section in this manual.

3. Cylinder Block Rear Plate

•

Tighten cylinder block rear plate fixing bolts to the
specified torque.

Rear Plate Bolt Torque

N∙m (kg∙m/lb∙ft)

82 (8.4/61)

2. Flywheel

•

Apply engine oil to fixing bolts.

•

Tighten the flywheel bolts to the specified torque in two
steps using the Angular Tightening Method.
Follow the numerical order shown in the illustration.

Flywheel Bolt Torque

N∙m (kg∙m/lb∙ft)

1st Step (Snug Torque)

2nd Step (Final Torque)

59 (6.0/43)

60° - 90°

1. Cylinder Head Assembly

1) Hot plug
•

Set the nock ball in the positioning groove on the
cylinder head side according to the order of the
cylinders, and hit it lightly with a plastic hammer.

NOTE:

After being pressed into the cylinder head, the hot
plugs were provided with surface grinding.
Accordingly, their dimensions are different
individually among them, and take care not confuse
the order of the cylinders.

6A-22-1.tif

6A-22-2.tif

GENERAL ENGINE MECHANICAL 6A – 23

When replacing the hot plug with new one:

When assembling a new hot plug, set the knock ball in the
positioning groove on the cylinder side and hit it lightly with
a plastic hammer until the hot plug is set in stably.
With patch attached to the hot plug to prevent it from
being damaged, press it in with a force of 4.5 ~ 5.5 ton
applied.
2) Valve Seat Insert Installation
1. Carefully place the attachment

(having a smaller

outside diameter than the valve seat insert) on the
valve seat insert

NOTE:

The smooth side of the attachment must contact the
valve seat insert.
2. Use the bench press

to gradually apply pressure to

the attachment and press the valve seat insert into
place.

NOTE:

Do not apply an excessive amount of pressure with
the bench press. Damage to the valve seat insert will
result.

Measure the height of the valve guide upper end from
the upper face of the cylinder head.

Valve Guide Upper End Height (H) (Reference)

mm (in)

13 (0.51)

NOTE:

If the valve guide has been removed, both the valve
and the valve guide must be replaced as a set.
3) Spring Lower Seat
4) Valve Stem Oil Seal
5) Valve
6) Valve Spring
7) Split Collar
Above works refer to “VALVE” Section in this manual.

6A-23-1.tif

6A-23-2.tif

Content .. 19 20 21 22 ..