Isuzu N-Series. Service manual — part 303

00-24 SERVICE INFORMATION

Item

Preheating system

Quick-On-Start System II

Exhaust system

Pipe outside diameter

× Thickness

Front pipe

mm (in)

60.5

× 2.0 (2.38 × 0.079)

Middle pipe

mm (in)

60.5

× 2.0 (2.38 × 0.079)

Rear pipe

mm (in)

60.5

× 1.6 (2.38 × 0.063)

Silencer type

Silencer with built-in catalytic

converter (platinum)

Silencer with built-in catalytic

converter (iron oxide)

Inside diameter

mm (in)

Approximately 200 (7.87)

Exhaust gas recirculation system
(EGR)

Equipped

Equipped (cooled)

Engine Model

4HE1-TC (4HE1-XS, XN)

98EPA

4HE1-TC (4HE1-XS)

SPEC. EURO3

SERVICE INFORMATION 00-25

SERVICE STANDARD

Engine

Cylinder Head

Cylinder Head Gasket Selection
Remarks:
The grade mark of the cylinder head gasket is shown by
semicircular notches on the left side of the front portion
of the gasket.

4HF1/4HF1-2/4HG1-T
Cylinder Head Gasket Selection

Item

Service Standard

Service Limit

Compression Pressure

KPa (kg / cm

2

/ psi) /

rpm

3040 (31 / 441) or more

Variance in pressure between the cylin-

ders: less than 294 (3 / 43) / 200

2,157 (22 / 312)

Item

Service Standard

Service Limit

Inlet and Exhaust Valve Seat Depression

mm (in)

0.7 — 1.2 (0.028 — 0.047)

2.5 (0.098)

Measurement should be taken by using
a new valve.

Cylinder Head Lower Face Warpage

mm (in)

0.05 (0.002) or less

0.2 (0.008)

Do not regrind the cylinder head lower
face.

Manifold Fitting Face Warpage

mm (in)

0.05 (0.002) or less

0.2 (0.008)

Water Leak Test

kPa (kg / cm

2

/ psi)

490 (5 / 71) — 3 minutes

Repair or replace
those having water
leak.

N6A1400E

N6A1401E

00-26 SERVICE INFORMATION

4HE1-TC
Cylinder Head Gasket Selection

Camshaft

N6A1404E

Item

Service Standard

Service Limit

Cam Height

mm (in)

52.75 — 52.91 (2.076 — 2.083)

51.8 (2.039)

Camshaft Journal Uneven Wear

mm (in)

0.015 (0.0006) or less

0.05 (0.002)

Camshaft Journal Wear

mm (in)

39.950 — 39.975 (1.5728 — 1.5738)

39.850 (1.569)

Camshaft Journal and Bearing Clear-
ance

mm (in)

0.025 — 0.087 (0.00098 — 0.00343)

0.15 (0.0059)

Camshaft Run-Out

mm (in)

0.04 (0.0016) or less

against the adjacent journal

0.05 (0.002)

N6A1407E

SERVICE INFORMATION 00-27

Rocker Arm and Rocker Arm Shaft

Valve

Item

Service Standard

Service Limit

Rocker Arm Shaft Wear

mm (in)

21.979 — 22.000 (0.8653 — 0.8661)

21.85 (0.860)

Rocker Arm Bushing Wear

mm (in)

22.010 — 22.035 (0.8665 — 0.8675)

22.15 (0.872)

Rocker Arm and Rocker Arm Shaft
Clearance

mm (in)

0.010 — 0.056 (0.0004 — 0.0022)

0.2 (0.008)

Rocker Arm Shaft Run-Out

mm (in)

0.3 (0.012)

Rocker Arm Roller and Pin Clearnace

mm (in)

0.040 — 0.084 (0.0016 — 0.0033)

0.5 (0.020)

Roller Surface

When there is an
excessive wear or
deformation found,
replace it.
When it is dam-
aged only slightly,
correct it with an oil
stone.

Item

Service Standard

Service Limit

Valve Stem Wear

mm (in)

Inlet

8.946 — 8.961

(0.3522 — 0.3528)

8.88 (0.35)

Exhaust

8.921 — 8.936

(0.3512 — 0.3529)

8.80 (0.34)

Valve Stem and Valve
Guide Clearance

mm (in)

Inlet

0.038 — 0.071

(0.0015 — 0.0028)

0.20 (0.0079)

Exhaust

0.064 — 0.096

(0.0025 — 0.0038)

0.25 (0.0098)

Valve Guide and Cylinder
Head Interference

mm (in)

0.005 — 0.040 (0.0002 — 0.0016)

Press it in with the valve guide applied
with engine oil.

Valve Thickness

mm (in) Inlet

Nominal size 1.80 (0.071)

1.3 (0.051)

Exhaust

Nominal size 1.75 (0.069)

1.3 (0.051)

Valve Contact Width

mm (in) Inlet

Nominal size 2.5 (0.098)

3.0 (0.118)

Exhaust

Nominal size 2.0 (0.079)

2.5 (0.098)

N6A1408E

N6A1409E