Isuzu N-Series. Manual - part 565

GENERAL ENGINE MECHANICAL 6A-17

CAMSHAFT, TAPPET

Component

Disassembly

1. Cylinder Head Assembly
2. Flywheel
3. Cylinder Block Rear Plate
4. Oil Pan Assembly
5. Oil Pump Assembly
6. Camshaft Timing Gear (Gear Drive Model)

• Remove the camshaft timing gear bolt from the

camshaft.

Notice:
Hold the camshaft stationary to prevent the camshaft
from turning.

• Use the universal puller (1) to pull out the cam-

shaft timing gear (2).

• Universal Puller: 5-8521-0002-0

Remove the thrust plate (3).

Legend

1. Cylinder head assembly

7. Camshaft timing pulley

2. Flywheel

8. Camshaft thrust plate

3. Cylinder block rear plate

9. Camshaft pulley center

4. Oil pan assembly

10. Camshaft

5. Oil pump assembly

11. Tappet

6. Camshaft timing gear

N6A3092E

6A-18 GENERAL ENGINE MECHANICAL

7. Camshaft Timing Pulley (Belt Drive Model)

• Use the timing pulley puller (2) to remove the

pulley.
Timing Pulley Puller: 5-8840-0086-0

• Remove the stopper bolt.

8. Camshaft Thrust Plate (Gear Drive Model)
9. Camshaft Pulley Center (Belt Drive Model)

10. Camshaft
11. Tappet

Inspection and Repair

Make the necessary adjustment, repairs, and part re-
placements if excessive wear or damage is discovered
during inspection.

1. Measure the Camshaft Thrust Clearance

• Use a dial indicator to measure the camshaft

end play.
This must be done before removing the cam-
shaft gear.

If the camshaft end play exceeds the specified
limit, the thrust plate must be replaced.

2. Camshaft Journal Diameter

• Use a micrometer to measure each camshaft

journal diameter in two directions (1) and (2). If
the measured value is less than the specified
limit, the camshaft must be replaced.

N6A3093E

N6A3094E

Camshaft End Play

mm (in)

Standard

Limit

0.08 (0.0031)

0.2 (0.0079)

Journal Diameter

mm (in)

Standard

Limit

49.945 — 49.975 (1.9663 — 

1.9675)

49.60 (1.9528)

N6A3095E

N6A3096E

GENERAL ENGINE MECHANICAL 6A-19

3. Cam Height

• Measure the cam height H with a micrometer. If

the measured value is less than the specified
limit, the camshaft must be replaced.

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.

• 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

Cam Height

mm (in)

Standard

Limit

42.02 (1.6543)

41.65 (1.6398)

Run-Out

mm (in)

Standard

Limit

0.02 (0.008) or less

0.10 (0.0039)

N6A3097E

N6A3098E

Camshaft Bearing Inside Diameter

mm (in)

Standard

Limit

50.00 — 50.03 (1.9685 — 1.9696)

50.08 (1.9716)

Camshaft Bearing Clearance

mm (in)

Standard

Limit

0.025 — 0.085 (0.0010 — 0.0033)

0.12 (0.005)

N6A3099E

6A-20 GENERAL ENGINE MECHANICAL

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

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.

Notice:
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 re-
placed.

Tappet Outside Diameter

1. Measure the tappet outside diameter with a mi-

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

N6A3100E

N6A3101E

Legend

1. Normal contact
2. Cracking
3. Pitting
4. Irregular contact
5. Irregular contact

Tappet Outside Diameter

mm (in)

Standard

Limit

12.97 — 12.99 (0.510 — 0.511)

12.95 (0.509)

N6A3102E