QUANCHAI N485D User manual

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Engine Maintenance Manual
(Quanchai N485D and N490D Diesel Engine for generator)
ANHUI QUANCHAI ENGINE CO., LTD
Jul 2019

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Preface
The N485D, N490D diesel engines are four-cylinder, in-line, water-cooled, four-stroke diesel
engines, which has the advantages of compact structure, beautiful appearance, easy to operate,
good rigidity, stable performance, long service life, good economical efficiency and high
serialization, etc. It is the ideal power unit for diesel generator set. However, the good
performance of product is closely associated with a good care. In order to make the user be
familiar with the structure and performance of the diesel engine, and correctly judge & maintain
its faults, this manual is prepared with pictures and words for the user to know the diesel engine
well, which is an important guarantee for better performance, good reliability and long service
life of the diesel engine.
The main purpose of this manual is to give users a better understanding of the diesel engine.
Therefore, the manual consists of various assembly views, detailed descriptions of disassembly
and assembly, step-by-step instructions of judgment, maintenance and repair, though which
users can operate and maintain the diesel engine well and master the operation and maintenance
technologies as soon as possible to ensure the normal, reliable and efficient operation of diesel
engine.

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Contents
Preface ........................................................................................................................................................ 2
Part 1 Overview .................................................................................................................................................. 6
Chapter 1 Safety Precautions ..................................................................................................................... 6
1. Scald proof sign .............................................................................................................................. 6
2. Anti-touch sign ............................................................................................................................... 6
3. Engine lifting equipment ................................................................................................................ 7
Chapter 2 Technical Parameters ................................................................................................................. 8
1. Main technical parameters .............................................................................................................. 8
2. Filling capacity ............................................................................................................................. 10
3. Main structural parameters of diesel engine ................................................................................. 11
4. Torque ........................................................................................................................................... 12
5. Outline dimension parameters ...................................................................................................... 12
6. Exposed parts of the engine .......................................................................................................... 17
Chapter 3 Fuel and Engine Oil ................................................................................................................. 19
1. Use of and precautions of fuel ...................................................................................................... 19
2. Engine lubricating oil ................................................................................................................... 21
3. Engine coolant .............................................................................................................................. 21
Chapter 4 Product Features and Accessories .................................................................................... 22
1. Standard accessories for the product ............................................................................................ 22
2. Optional accessories ..................................................................................................................... 22
Part 2 Disassembly, Assembly and Adjustment ............................................................................................... 23
Chapter 1 Disassembly and Assembly of Valve Train .............................................................................. 23
1. Maintenance equipment and tools ................................................................................................ 23
2 Torque requirements and dimensional data ................................................................................... 23
3. Disassembly of valve train ........................................................................................................... 26
4. Assembly of valve train ................................................................................................................ 31
Chapter 2 Disassembly and Assembly of Crank Linkage Mechanism ..................................................... 47
1. Maintenance equipment and tools ................................................................................................ 47
2 Torque requirements and dimensional data ................................................................................... 47
3. Disassembly of crank linkage mechanism ................................................................................... 50
4. Assembly of crank linkage mechanism ........................................................................................ 54
Chapter 3 Cooling System ........................................................................................................................ 63
1. Maintenance equipment and tools ................................................................................................ 63
2 Torque requirements and dimensional data ................................................................................... 63
3. Disassembly, assembly and adjustment of cooling parts .............................................................. 64
4. Assembly and adjustment of cooling parts ................................................................................... 67
Chapter 4 Lubrication System .................................................................................................................. 69
1. Maintenance equipment and tools ................................................................................................ 69
2 Torque requirements and dimensional data ................................................................................... 69
3. Disassembly of the lubrication parts ............................................................................................ 70
Chapter 5 Starting System ........................................................................................................................ 72
1. Maintenance equipment and tools ................................................................................................ 72
2. Torque requirements ..................................................................................................................... 72
3. Disassembly, assembly and adjustment of starting parts .............................................................. 73

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Chapter 6 Fuel supply system .................................................................................................................. 74
1. Maintenance equipment and tools ................................................................................................ 74
2 Torque requirements and dimensional data ................................................................................... 74
Chapter 7 Disassembly, Assembly and Adjustment of Accessories ......................................................... 79
1. Data and dimensions .................................................................................................................... 79
2. Disassembly and assembly of gear chamber ................................................................................ 80
4. Atomization of nozzle .................................................................................................................. 82
Part 3 Inspection, Adjustment, Fault Diagnosis and Removal ........................................................................ 84
Chapter 1 Dynamic Checks ...................................................................................................................... 84
1. Overview ...................................................................................................................................... 84
2. Checks on engine oil level ............................................................................................................ 85
3. Checks on level and status of coolant ........................................................................................... 86
4. Checks on fan and belt ................................................................................................................. 87
5. Checks on fuel system .................................................................................................................. 88
6. Checks on inlet and exhaust systems ............................................................................................ 89
7. Checks on electrical system ......................................................................................................... 90
8. Idle test on engine......................................................................................................................... 91
Chapter 2 Working Mechanism ................................................................................................................ 92
1. Valve train..................................................................................................................................... 92
2. Crank linkage mechanism ............................................................................................................ 94
3. Cooling system ............................................................................................................................. 97
4. Lubrication system ....................................................................................................................... 99
5. Electrical system ........................................................................................................................ 100
6. Fuel system ................................................................................................................................. 105
Chapter 3 Inspection and Adjustment..................................................................................................... 106
2. Cylinder pressure ........................................................................................................................ 108
3. Timing detection of fuel injection pump .................................................................................... 109
4. Calibration of fuel injection pump ............................................................................................. 110
5. Atomization of fuel injector ........................................................................................................111
6. Test on engine oil pressure ......................................................................................................... 112
7. Inspection and adjustment of starter pinion ................................................................................ 114
Chapter 4 Fault Diagnosis and Removal ................................................................................................ 115
1. Emission of white smoke ........................................................................................................... 115
2. Emission of blue smoke ............................................................................................................. 116
3. Emission of black or gray smoke ............................................................................................... 117
4.Cylinder compression pressure being insufficient ....................................................................... 118
5. Blocked air filter ......................................................................................................................... 119
6. Emission of blue smoke ............................................................................................................. 119
7. Abnormal sound emitted by diesel engine .................................................................................. 120
8. Abnormal operation or frequent flameout .................................................................................. 121
9. Low power .................................................................................................................................. 122
10. Engine oil-water mixture .......................................................................................................... 124
11. Surging rotating speed .............................................................................................................. 125
12. Unstable rotating speed ............................................................................................................ 126
13. Engine overheat ........................................................................................................................ 126
14. Abnormal coolant temperature ................................................................................................. 127

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15. No oil pressure or too low oil pressure ..................................................................................... 128
16. Too high engine oil pressure ..................................................................................................... 128
17. Overheated engine oil ............................................................................................................... 129
18. High engine oil consumption ................................................................................................... 130
19. Low starting speed.................................................................................................................... 131
20. Failure of engine to be started .................................................................................................. 132
21. Failure of starter to work .......................................................................................................... 133
22. Idling starter and failure of engine to work .............................................................................. 134
23. Under-power starter .................................................................................................................. 134
24. Screams emitted during/after start or hard to disconnect pinion .............................................. 135
25. Methods for distinguishing between starter failure and storage battery failure........................ 136
26. Checks on disassembled starter ................................................................................................ 137
27. Hard to get diesel engine started .............................................................................................. 138
28. Emission of black smoke .......................................................................................................... 139

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Part 1 Overview
Chapter 1 Safety Precautions
This sign is a safety sign. If the diesel engine
is made with such sign or mark, care must be
taken to ensure safety and prevent personal
injury.
The operation procedures and safety
precautions must be followed.
1. Scald proof sign
After the engine is started, personnel shall be
kept away from the engine by 50 cm.
2. Anti-touch sign
It is prohibited to touch the heating device such as the engine body when it is in operation.
The engine can only be repaired after half an hour of downtime.
See the manual for other signs.

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3. Engine lifting equipment
When lifting the engine, use the allowable
type of lifting equipment with correct lifting
capacity. Particularly, when lifting the engine
vertically, adopt the lifting equipment shown
in the figure, directly connect it to the engine
lifting ring. In addition, do not lift the engine
when only single lifting ring is connected.
Before lifting the engine, check whether the
lifting ring is damaged or tightened. The
tightening torque of positioning screw of the
engine lifting ring is 44 N·m.

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Chapter 2 Technical Parameters
1. Main technical parameters
Note: Product design and technical parameters are subject to change without notice.
Model N485D N490D
Type Four cylinders, in line, water cooling, four stroke
Type of combustion
chamber Direct injection
Intake mode Natural aspiration
Cylinder diameter (mm) 85 90
Piston stroke (mm) 95 100
Mean piston speed (m/s) 4.75 5.70 5.0 6
Mean effective pressure of
piston (kPa) 630 618 723 708
Total displacement (L) 2.156 2.545
Compression ratio 18：1 18：1
Declared power (kW) 17 20 23 27
Declared speed (r/min) 1500 1800 1500 1800
Stable speed governing rate
(%) ≤ 5
Fuel consumption rate at
declared working condition
(g/kW·h)
≤ 245
Engine oil consumption rate
(g/ kW·h) ≤1.63
Crankshaft rotating direction
(facing flywheel) Counterclockwise
Cooling method Water cooling, forced circulation
Lubrication method Force-feed and splash lubrication
Starting mode Motor start
Ignition order 1-3-4-2

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N485D power curve
N490D power curve

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2. Filling capacity
Item Unit FOTON
N485D N490D
Water volume in diesel engine
body L 4.1
Capacity of engine oil pan 6.5

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3. Main structural parameters of diesel engine
Rotating direction (facing
flywheel) CCW
Number of flywheel teeth 109
Specifications of flywheel housing
SAE4＃
Specifications of flywheel SAE7.5″
Mode of fuel injection Direct injection
Speed governor Mechanical type
Fuel supply pump Mechanical type
Diameter of fuel injector nozzle 0.25 mm
Opening pressure of fuel injector 2±0.5 MPa
Diesel filter Single stage
Lubricating System
Grade of lubricating oil CD-40
Capacity of lubricating oil 6.5 L
Maximum allowable temperature
of engine oil 115℃
Engine oil
pressure:
Maximum 650 kpa
Minimum 100 kpa
Cooling System
Cooling method Water cooling
Pump flow 80 L/min (3000 rpm, with 5 m of pump head)
Water capacity of engine 4.1 L
Maximum water temperature 95℃
Open/full open temperature of
thermostat 70℃/82℃
Diameter of exhaust fan (mm) φ410
Electrical system
Specifications of generator 14 V×500 W
Pressurizer Built-in pressurizer (none in partial states)
Starting motor 12 V×3 kW
Battery voltage 12 V
Battery capacity ≥ 100Ah (recommended)
Intake and exhaust flow
Intake flow (kg/h) 58
Exhaust flow (kg/h) 60.5
Speed sensor
Interface of speed sensor M18X1.5 or M16X1.5
Distance form mounting surface
of speed sensor to top of ring gear
34 mm
Valve layout
Valve type Roof mounted
Number of valves per cylinder One intake valve and one exhaust valve
Valve clearance Intake valve: 0.2 ~ 0.25 mm
Exhaust valve: 0.25 ~ 0.3 mm

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4. Torque
Serial
No. Description Torque Note
N.m
1 Cylinder head bolt 145 ~ 155
2 Through bolt of rocker shaft
support 21 ~ 25
3 Cylinder head nut 21 ~ 25
4 Connecting rod bolt 60 ~ 70
5 Bolt of main bearing shell cap 140 ~ 160
6 Connection of the pump to the
cylinder head and the body 25
7 Assembly of the engine oil
pump to the body 25
8 Connecting of the starting
motor to the flywheel housing 80
9 Connecting of the fuel injection
pump to the gear chamber 70
10 Injection nozzle nut 40 ~ 60
5. Outline dimension parameters
Outli
ne
dime
nsion
s
Length
mm
760
Width 550
Height 608
Width of oil pan mm 262
Height from pump to crankshaft
center mm 202
Fan diameter mm 410
Weight kg 205 (without water tank, air filter and silencer)

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Left view:

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Front view:

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Right view:

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Rear view:

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6. Exposed parts of the engine
6.1 Left side of the engine
1 Pump parts 2 Thermostat outlet 3 Intake pipe 4 Intake heater 5 Air filter 6 Fuel injector 7
Fuel return pipe of fuel injector 8 Cylinder head cover 9 Lifting lug 10 Flywheel housing 11
Fan 12 Fan pad 13 Advancer cover 14 Gear cover 15 Gear chamber 16 Front bracket 17 Fuel
injection pump 18 High-pressure fuel pipe 19 Engine oil filter 20 Oil pan 21 Inlet and outlet
pipe of diesel filter 22 Engine body 23 Diesel filter 24 Flywheel

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6.2 Right side of the engine
25 Fuel filler cap 26 Lifting lug 27 Crankshaft pulley 28 V belt for vehicle 29 Generator 30
Generator bracket 31 Front bracket 32 Cylinder head part 33 Respirator outlet pipe 34
Respirator part 35 Exhaust connecting pipe 36 Exhaust pipe 37 Starting motor

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Chapter 3 Fuel and Engine Oil
1. Use of and precautions of fuel
1.1 Storage of fuel
If the diesel in the fuel tank or transport tank
flows slowly, add the fuel conditioner to the
diesel to prevent the water from concentrating .
Please purchase high-quality clean fuel from a
reputable dealer.
It is very important to store the fuel properly.
Store the fuel in clear tank and warehouse, and
regularly drain water and sediment from the
bottom of tank.
It is avoided to store the fuel for a long time. If
the fuel is consumed slowly in the fuel tank or
storage tank, add fuel conditioner to the tank
to prevent the water from concentrating.
Keep fuel in an easily accessible place, and
stay away from buildings.
Note: In order to reduce the separation of fuel
gelling with control wax in cold weather, fuel
or bulk storage cabinets can be added.

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1.2 Precautions for use of fuel
Fuel: The fuel is the light diesel specified in
GB/T252. And the minimum applicable
temperature is shown in the following table:
Grade of light
diesel
0# -10# -20# -35# -50#
Minimum applicable
temperature
4℃ -5℃ -14℃ -29℃ -44℃
The user can select the light diesel oil
according to local ambient temperature. In
most areas of China, 0# light diesel may be
used in summer, while -10# light diesel may
be in winter. In special cases, for instance, in
Northeast China, -35# light diesel may be used,
while in hot areas such as Guangdong, 10#
light diesel may be used.
1.3 Fuel filling
Fill the fuel according to the fuel level shown
on the dipstick of the fuel tank.