Isuzu N-Series. Manual - part 500

Engine Mechanical (4HK1-TC)   6A-105

• Apply engine oil on the piston pin. Use your

finger to push it in hole of the piston and rotate
it. If the pin smoothly rotates without instability,
the clearance is normal. If there is instability,
measure the clearance. If the clearance
exceeds the limit, replace the piston and the
piston pin.

11. Remove the bush.

• Set the collar, connecting rod and collar on the

setting bar as shown in the drawing.

• Tighten the nut.

Legend

1. Setting Bar
2. Connecting Rod
3. Nut
4. Collar
5. Bush
6. Collar

 

• Place the connecting rod bush replacer base on

press, tighten the fixation bolt.

• Use the bench press to replace the bush.

Special tool
Connecting rod bush replacer: 5-8840-2340-0
(EN-47682)

Legend

1. Bolt
2. Connecting Rod Bush Replacer

 

12. Measure the connecting rod alignment.

• Use a connecting rod aligner to measure the

parallelism of the big end hole and the small
end hole. If the measured value exceeds the
limit, replace it.

Piston pin and piston pin hole clearance

mm (in)

Standard

0.004 – 0.017 (0.00016 – 0.00067)

Limit

0.04 (0.0016)

N6A6199E

Connecting rod alignment
(par length of 100 mm (3.94 in))

mm (in)

Standard

Limit

Distortion and 
Parallelism

0.05 (0.002)

0.20 

(0.008)

N6A6200E

N6A6201E

6A-106   Engine Mechanical (4HK1-TC)

13. Measure the bearing oil clearance.

• Measure the oil clearance between the

connecting rod bearing and the crank pin with
the following method.

- Remove the connecting rod cap. Sort the

removed caps according to the cylinder
number.

- Clean the bearing and the shaft pin.
- Inspect the bearing. If it is damaged or worn

seriously, replace the entire bearing.

• Place the plastigauge on the crankshaft pin.
• Install the bearing cap and tighten the bolt with

the designated torque.
Apply molybdenum disulfide on the screw part
and the bearing surface.

Tighten:
Connecting rod bearing cap bolt to
1st step: 39 N

⋅m (4.0  kg⋅m/29 lb⋅ft)

2nd step: 60

° (degrees)

3rd step: 30

° (degrees)

Caution:
Do not rotate the crankshaft.

- Remove the cap.
- Measure the largest width of the plastigauge

to calculate the oil clearance. If the
clearance exceeds the limit, replace the
entire bearing.

- Remove the plastigauge from the bearing

and crankpin.

14. Select the connecting rod bearing.

• Select bearings carefully by the grade of big

end hole diameter of the connecting rod
according to the selection table.

Legend

1. Top and Back Recognition Boss
2. Big End Diameter Grade Mark
3. Cylinder Number

 

Bearing selection table

Crankpin and bearing clearance

mm (in)

Standard

0.037 – 0.077 (0.0015 – 0.0030)

Limit

0.10 (0.0039)

N6A6202E

Big end hole 

diameter

Grade

Bearing

recognition 

color

Oil clearance

mm (in)

A

Green

0.037 – 0.077

(0.0015 – 0.0030)

B

Yellow

0.037 – 0.077

(0.0015 – 0.0030)

N6A6203E

1

1

2

3

N6A6648E

Engine Mechanical (4HK1-TC)   6A-107

Legend

1. Grade Recognition Color

 

Reassembly

1. Install the bush

• Place the connecting rod bush replacer base on

a press, set the connecting rod and tighten the
fixation bolt.

Special tool
Connecting rod bush replacer: 5-8840-2340-0
(EN-47682)

Legend

1. Bolt
2. Connecting Rod Bush Replacer

 

• Set the collar, new bush and collar on the

setting bar as shown in the drawing.

• Tighten the nut.

• Adjust the oil hole of the connecting rod and the

oil hole of the bush, and use the bench press to
install the bush.

Legend

1. Setting Bar
2. Connecting Rod
3. Nut
4. Collar
5. Bush
6. Collar

 

• After installing the new bush, use a grinder to

machine the pin hole so that the pin clearance
equals the standard value.

2. Install the piston.
3. Install the connecting rod.

• Install it so that the front mark of the head of the

piston and the connecting rod forging mark
(projecting) on the connecting rod face the
same direction.

N6A6205E

N6A6200E

N6A6199E

N6A6206E

6A-108   Engine Mechanical (4HK1-TC)

• Use snap ring pliers to install the snap ring of

one side.

Legend

1. Front Mark
2. Forging Mark (Projecting)

 

4. Apply enough engine oil on the piston pin, push it

in the piston and the connecting rod small edge.

5. Use snap ring pliers to install the snap ring.

Caution:
Make sure that the snap ring is installed in the ring
groove properly. Make sure that the connecting rod
moves smoothly.

6. Use ring pliers to install the piston ring.

• Install the oil ring so that the joint angle of the

ring and coil expander is in the opposite 180

°

direction.

• Install 2nd and 1st compression rings in this

order so that the marks “2T” and “1T” face
upward.

Legend

1. Oil ring
2. Compression Ring 2nd
3. Compression Ring 1st

 

Caution:
Note that the shapes of compression rings 1st and 2nd
are different.
Make sure that there is no gap in the position indicated
in the drawing when the oil ring coil expander was
installed.

Installation

1. Install the connecting rod bearing.

• Install the bearing on the connecting rod, apply

engine oil on the bearing.

2. Install the piston and connecting rod assembly.

1

2

N6A6645E

N6A6208E

N6A6209E

N6A6210E