Foton Series Light Bus. Service Manual — part 4

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·40·

First

44

Second

90° turning

Cylinder block x cylinder head

Third

90° turning

First

44

Cylinder block x crankshaft main bearing cap

Second

90° turning

First

25

Connecting rod x connecting rod bearing cap

Second

90° turning

Crankshaft x crankshaft pulley

245

Camshaft x distributor drive gear

74

Crankshaft x flywheel

88

Crankshaft x drive plate

74

Oil pan x oil plug

25

Alternator x bracket

59

Engine mounting isolator x engine mounting bracket

44

Intake manifold x TVSV

25

Coolant bypass flange x thermostat

25

EGR valve x intake manifold

20

EGR valve x EGR pipe

20

Exhaust manifold x EGR pipe

20

Fuel outlet pipe x intake manifold

20

Fuel outlet pipe x injector cover

4.4

NO 1 fuel supply pipe x fuel outlet pipe

29

No 1 fuel supply pipe x fuel filter

29

Cold start injector pipe x cold start injector

20

Cold start injector pipe x fuel outlet pipe

20

Pressure regulator x fuel outlet pipe

25

Chapter 1 Main Data and Specification of VIEW Series Light-bus

·41·

1.5.5.2 Bolt standard tightening torque

Mark grade

Mark grade

No. mark on bolt head

4- 4T

5- 5T

6- 6T

7- 7T

8- 8T

9- 9T

10- 10T

11- 11T

Stud

W/o mark

4T

Hex bolt

W/o mark 4T

Hex flange bolt w. washer

Hex head bolt

W/o mark 4T

With slot

6T

Hex bolt

Two projecting lines 5T

Hex flange bolt w. washer

Hex head bolt

Two projecting lines 6T

Hex bolt

Two projecting lines 7T

Hex bolt

Four projecting lines 8T

Welding bolt

4T

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·42·

Specified tightening torque – standard bolts

Specified torque

Hex bolt

Hex flange bolt

Rating

Diameter (mm)

Pitch (mm)

N-m

N-m

6

1

5

6

8

1.25

12.5

14

10

1.25

26

29

12

1.25

47

53

14

1.5

74

84

4T

16

1.5

115

--

6

1

6.5

7.5

8

1.25

15.5

17.5

10

1.25

32

36

12

1.25

59

65

14

1.5

91

100

5T

16

1.5

140

--

6

1

8

9

8

1.25

19

21

10

1.25

39

44

12

1.25

71

80

14

1.5

110

125

6T

16

1.5

170

--

6

1

10.5

12

8

1.25

25

28

10

1.25

52

58

12

1.25

95

105

14

1.5

145

165

7T

16

1.5

230

--

8

1.25

29

33

10

1.25

61

68

8T

12

1.25

110

120

8

1.25

34

37

10

1.25

70

78

9T

12

1.25

125

140

8

1.25

38

42

10

1.25

78

88

10T

12

1.25

140

155

8

1.25

42

47

10

1.25

87

97

11T

12

1.25

155

175

Chapter 1 Main Data and Specification of VIEW Series Light-bus

·43·

1.6 Model 4G64 Engine main technical specification

1.6.1 Model 4G64 S4 MPI engine performance curve

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·44·

1.6.2 Engine main technical parameters

SN

Description

Parameters

1

Model

Mitsubishi 4G64 S4 MPI

2

Type

In line, four cylinders, roof type combustion

chamber, SOHC 16 valves, four strokes, water

cooling, multi-point EFI gasoline engine

3

No.of cylinder

4

4

Cylinder bore (mm)

86.5

5

Piston stroke(mm)

100

6

Total displacement (L)

2.351

7

Compression ratio

9.5

8

Fuel injection and ignition sequence

1-3-4-2

9

Fuel rating

PON93 or above superior unleaded gasoline

(GB17930)

10

Oil rating

SE or above 10W-30 or 15W-40 (GB11121)

11

Oil volume (L)

4.3 (with 0.3L in oil filter)

12

Coolant volume (L)

8 (8.5 L with rear heater)

intake valve open

18° BTDC

Intake valve close

53° ABDC

Exhaust valve open

50° BBDC

13

Port timing

(Crankshaft turning angle)

Exhaust valve close

18° ATDC

14

Spark plug clearance (mm)

1±0.1

15

Cooling method

Forced close water cooling

16

Rated power / rated rpm (kw/rpm)

93/5250

17

Max torque/max torque rpm (N-m/rpm)

190.12/2750

18

Min. fuel consumption (g/kw/h)

258.4

19

Fuel consumption at limited operation (L/100km)

(for light bus)

8.54

20

Idle rpm

750±50

at idle

≥96

At 200 rpm

≥205

21

Oil pressure(KPa)

At 3000 rpm

≥386

CO%

1.0±0.5

22

Pollutant emission

HC(ppm)

2.≤500comply with GB18352.2

23

System fuel pressure (KPa)

300 ± 20

Chapter 1 Main Data and Specification of VIEW Series Light-bus

·45·

SN

Description

Parameters

24

Dimension (L×W×H) (mm)

695×635×632

25

Total mass (with engine, water pump, without clutch

and housing) (kg)

161.8

26

Thermostat opening temperature （℃）

82 (100 at fully open)

27

Ignition advance angle

5°± 2°BTDC

28

Lubrication method

Pressure and splashing

29

Crankshaft turning direction

Counter-clockwise (viewing from engine front)

30

Cylinder sleeve type

W/o sleeve

31

Fuel supply method

Multi-point EFI

32

Valve train

SOHC, 16 valves (2 intake/exhaust valves for

each cylinder)

Check value 5.5～8.5

new belt

5.5～7.5

33

Drive belt deflection (under 98N.m) (mm)

Alternator

Power steering pump

AC compressor pump used belt

7.5～8.5

34

Tensioner projection（mm）

3.8～4.5

1.6.3 Fitting sizes of engine main parts

Description

Standard

Limit

Tensioner arm projection (mm)

12

--

Alternator belt

Tensioner arm press-in ( 98～196N-m) (mm)

≤1

--

Intake

37.39

36.89

Cam height (mm)

Exhaust

36.83

36.33

Camshaft

Shaft diameter (mm)

45

Lower plane flatness (mm)

0.03

0.2

Surface grinding limit ★total grinding amount (block

and head) (mm)

★0.2

Total height (mm)

119.9～120.1

Cylinder head

Length of cylinder head bolt (mm)

97.4

≤99.4

Intake

1.0

0.5

Top edge thickness (mm)

Exhaust

1.2

0.7

Valve stem diameter (mm)

6.0

Intake

0.02～0.05

0.10

Radial clearance—valve stem and

guide (mm)

Exhaust

0.03～0.07

0.15

Top cone angle (degree)

45～45.5

--

Intake

112.30

111.80

Valve

Height (mm)

Exhaust

114.11

113.61

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·46·

Description

Standard

Limit

Free height

51

50.5

Operating pre-tension / operating height (N/mm)

267/433

--

Valve spring

Verticality (degree)

≤2

≤4

Contacting width (mm)

0.9～1.3

--

Inner diameter (mm)

6

--

Outer diameter (mm)

11

--

Press-in height (mm)

14

--

Valve guide

Valve stem projection (mm)

49.3

49.8

Description

Standard

Limit

Drive gear

0.08～0.14

--

Oil pump

Side clearance (mm)

Driven gear

0.06～0.12

--

Piston

Piston clearance (mm)

0.02～0.04

Top ring

0.02～0.06

0.1

Side clearance (mm)

Second ring

0.02～0.06

0.1

Top ring

0.25～0.35

0.8

Second ring

0.4～0.55

0.8

Piston ring

End clearance (mm)

Oil ring

0.10～0.40

1.0

Outer diameter (mm)

22.0

--

Press-in force (N)

7399～17150

--

Piston pin

Press-in temperature

Room

temperature

--

Radial clearance – connecting rod journal (mm)

0.02～0.05

0.1

Radial clearance – main journal (mm)

0.02～0.04

0.1

Main journal (mm)

57

--

Connecting rod journal (mm)

45

--

Crankshaft

Axial clearance – crankshaft (mm)

0.05～0.18

0.25

Connecting rod

Big end side clearance (mm)

0.10～0.25

0.4

Flatness—upper surface (mm)

0.05

0.1

Grinding limit (mm) – upper surface ▲ total

grinding of cylinder block and head (mm)

--

▲ 0.2

Total height (mm)

290±0.1

--

Inner diameter – bore (mm)

86.5～86.53

--

Cylinder block

Bore cylindricality (mm)

0.01

--

Chapter 1 Main Data and Specification of VIEW Series Light-bus

·47·

Description

Standard

Limit

0.05OS

11.05～11.07

0.25OS

11.25～11.27

Enlarged and second
processed size (mm) –
valve

guide

hole

(intake/exhaust)

0.50OS

11.50～11.52

0.30OS

34.435～34.455

Enlarged and second
processed size (mm) –
intake valve seat ring

0.60OS

34.735～37.755

0.30 OS

31.935～31.955

Cylinder head

Enlarged and second
processed size (mm) –
exhaust valve seat ring

0.60OS

32.235～32.255

Alternator

Rotor winding resistance (Ω)

3～5

--

1.6.4 Tightening torque of engine bolts

Tightening torque for main bolts

S.N.

Tightening location

Torque (N-m)

Rocker arm cap bolt

3.84

Bolt-rocker arm and camshaft assembly

31.4

Rocker arm and camshaft

Thrust cap bolt

18.6

Cylinder head bolt

1.96+90°~ +90°

Drain plug

44.1

Oil pan

6.86

Oil strainer bolt/nut

18.62

Oil pressure switch

9.8

Oil discharge plug

44.1

Bracket bolt – oil filter

18.62

Front cover bolt

23.52

Plug

23.52

Flange bolt

36.26

Bolt – oil pump cover

15.68

Oil pump front cover

Screw – oil pump cover

9.8

Connecting rod nut

19.6 +90°~ +90°

Flywheel bolt

132.3

Rear cover plate mounting bolt

10.78

Bell cover mounting bolt

8.82

Oil seal cover mounting bolt

10.78

Crankshaft, cylinder block and

flywheel

Main bearing cap bolt

24.5 +90°~ +90°

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·48·

S.N.

Tightening location

Torque (N-m)

Bracket bolt

4.9

Throttle position sensor

3.43

Idle air valve bolt

3.43

Throttle body

Mounting nut – idle speed adjusting screw

2.94

Cooling fan bolt

10.78

Fan clutch bolt

10.78

Alternator fixing bolt

23.52

Brace bolt

23.52

Pivot nut

22.54

Crankshaft pulley bolt

24.5

Spark plug

24.5

Distributor bolt

12.74

Ignition coil bolt

23.53

Alternator, ignition system

Locating bushing bolt – camshaft pulley

9.8

Bolt -- front lower cover

10.78

Bolt – tensioner

48.02

Bolt – tensioner arm

21.56

Bolt – auto tensioner

23.52

Bolt—center pulley

35.28

Brace bolt – tensioner

48.02

Bolt – timing belt rear cover

10.78

Timing belt indicator

8.82

Fixing bolt – oil pump pulley

53.9

Bolt – crankshaft pulley

117.6

Fixing bolt – tensioner “B”

18.62

Fixing bolt – balance shaft pulley

45.08

Bolt – camshaft pulley

88.2

Timing belt

Fixing bolt – balance shaft pulley

45.08

Throttle

18.62

EGR valve

21.56

Injector and distribution pipe

11.76

Fuel return pressure regulator

8.82

Fuel system

Intake manifold

8.82

Chapter 1 Main Data and Specification of VIEW Series Light-bus

·49·

S.N.

Tightening location

Torque (N-m)

Engine lug bolt

18.62

Engine coolant temperature sensing plug

29.4

Coolant outlet pipe joint bolt

19.6

Intake manifold bolt

19.6

Coolant temperature sensor

10.78

Intake manifold

Intake manifold bracket

13.72

Bolt – exhaust manifold cover

13.72

Joint bolt – coolant inlet pipe

23.52

Exhaust manifold nut (M8)

29.4

Exhaust manifold nut (M10)

49

Joint bolt – coolant bypass pipe

23.52

Bolt – coolant pipe sets

12.74

Bolt – thermostat case

23.52

Exhaust manifold

Water pump bolt

13.72

Tightening toque for ordinary bolts

Tightening torque for bolts and nuts

Torque ( N-m)

Bolt (with spring washer)

Flange bolt

Bolt diameter

Pitch

Head mark 4

Head mark 7

Head mark 10

Head mark 4

Head mark 7

M6

1.0

--

8.82

12.74

--

10.78

M8

1.25

10.78

17.64

29.4

13.72

23.52

M10

1.25

19.6

33.32

58.8

29.4

49

M12

1.25

35.28

60.76

105.84

53.9

88.2

Bevel pitch tightening torque

Torque ( N-m)

Pitch size

Light alloy

Cast iron, steel

NPTF 1/16

4.9～7.84

7.84～11.76

PT 1/8

7.84～11.76

14.7～21.56

PT1/4

19.6～29.4

34.3～44.1

NPTF 1/4

19.6～29.4

34.3～44.1

PT 3/8

39.2～53.9

53.9～73.5

PT 1/2

68.6～98

117.6～156.8

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·50·

Plastic area tightening method (bolt)

▲ The method is used on following bolts:

1. Cylinder head bolts

2. Main bearing cap bolts

3. Connecting rod bolts

▲ Tightening methods

Tightening the bolt for another 90～100 ° (two 90° for a cylinder head) after it has been tightened with

specified torque. Tightening method varies in different area. Observe the indicated methods in this book.

1.6.5 Sealant application

(1) Sealant

Sealant is used on relevant part of an engine. Special care should be taken to sealant applying amount,

applying location and state of applying face so as to obtain a good sealing. Insufficient applying will lead to poor

sealing and leaking, while over applying will lead to sealant overflow to block coolant / oil ducts. Correct sealant

applying requires consistent and even application on connecting surface, ensuring the whole connecting surface

has a layer of flat sealant.

(2) Remove sealant on connecting surface

It is usually easy to remove the sealant-combined parts. In some case, the process can apply a wood stick or

same tool to knock slightly to break the sealant on connecting surface. A flat and smooth sealant scraper can also

be used for removing (insert it into connecting surface), but be sure not to injure the surface. Use oil pan special

tool (MD998727) to remove engine oil pan.

(3) Clean the connecting surface

Clear dirt on the surface with a sealant scraper or a wire brush to make sure the surface is flat and smooth,

free from oil stain and dirt. Note to remove the sealant on mounting holes and thread holes.

(4) Applying tips

Apply sealant evenly on specified diameter to circle the mounting hole. Mount parts while sealant is still wet

(with 15 minutes). Leave enough time for sealant to harden after parts-mounting (around 1 hour). Do not apply oil

on applying area or run the engine during the period.

(5) Sealant application location

Location

Sealant rating

Coolant outlet pipe joint

MD970389 or equivalent

Coolant bypass pipe joint

MD970389 or equivalent

Coolant temperature unit

3MATD No. 8660 or equivalent

Oil pan

MD970389 or equivalent

Oil seal cover

MD970389 or equivalent

Oil pressure switch

3MATD No. 8660 or equivalent

Coolant temperature sensor

3M NUT LOCKING NO.4171 or equivalent

Chapter 2 Vehicle Technical Maintenance

·51·

Chapter 2 Vehicle Technical Maintenance

With the improvement of vehicle technology and quality, vehicle maintenance becomes more important.

Vehicle maintenance should be performed regularly based on preventive and forcible principles.

Vehicle maintenance procedures are arranged according to gradual changes of vehicle technical conditions,

and they should be preformed before these conditions become deteriorated. Therefore, vehicle maintenance is of

preventive nature. To perform forced maintenance according to maintenance interval and technical requirements

will keep vehicle clean and tidy, pinpoint and remove timely potential faults so as to prolong vehicle service life.

2.1 Routine maintenance

Vehicle parts tend to become loose, worn-out and damaged during vehicle’s operation, which harm vehicle’s

performance. Routine maintenance carried out by driver will reverse these effects and keep vehicle in a proper

working condition. Driver keeps watching vehicle’s technical conditions by means of routine maintenance is very

important to drive safely and avoid accident.

2.1.1 Routine maintenance procedures

a.

Before, within and after using vehicle, check safety mechanism and fittings for fastening;

b.

Keep oil, air, fuel filters and battery surface clean;

c.

Avoid fuel, water, air and electricity from leaking.

These steps will keep vehicle in a clean look and good working condition.

Figure 2-1 Vehicle routine maintenance procedures

Category

Procedures

External 1. Check and clean mirrors outside driver cab, windshield and window glasses;

2. Check vehicle appearance, paint and corrosion on body;

3. Check tyre adjustment and wheel lugs’ fastening.

4. Check and adjust windshield wiper;

5. Check and lubricate door hinges and engine hood;

6. Check and adjust battery fluid level or check battery gravity indication.

Interior

7. Check vehicle for any leaks;

8. Check and adjust vehicle lights and signals;

9. Check and adjust horn;

10. Check wiper and windshield washer;

11. Check windshield defroster;

12. Check and adjust rear view mirrors and sun-shield;

13. Check steering wheel free travel and its operation.

14. Check gas pedal performance;

15. Check clutch/brake pedals free travels and their travel smoothness at depressing and releasing;

16. Check brake performance;

17. Check parking brake performance.

Engine

compartme

nt

18. Check and add engine oil;

19. Check and add engine coolant;

20. Check and add windshield washer fluid;

21. Check and add fluid to brake master cylinder and clutch master cylinder.

22. Check and clean air filter element.

23. Check engine intake / exhaust systems for fastening.

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·52·

2.1.2 Procedures for routine vehicle maintenance

Before, within and after using vehicle, it is suggested to perform routine maintenance procedures indicated

with following flow chart (figure 2-1):

Figure 2-1 Routine maintenance flow chart

2.2 First level maintenance

For 1

st

level maintenance, the interval or mileage are 6 months or 7500km－15000km respectively, whoever

comes first will override. First maintenance is carried out by service technician, it focuses on cleaning, fastening

and lubricating procedures beside these have made in routine maintenance procedures, and also includes checks

on safety-related devices such as brake and operating mechanisms.

2.2.1 Procedures for 1

st

level maintenance (see chart 2-2)

Chart 2-2 Procedures for 1

st

level maintenance

Engine

1. Check lubricating, cooling, exhaust and fuel systems for leakage or damage;

2. Replace engine oil and oil filter element;

3. Check coolant level and its frozen-proof capability, add coolant or adjust coolant concentration

if necessary;

4. Clean air filter, replace filter element if necessary.

5. Check drive belt condition and tension, adjust belt tension or replace belt if necessary.

Chassis

6. Check clutch pedal travel;

7. Check transmission for leakage or damage;

8. Check UJ boot for damage;

9. Check tie rod ball joint for fastening and clearances, and check if boot is damaged;

10. Check brake system for leakage or damage;

11. Check brake fluid level, add fluid if necessary;

Check and clean

Fastening and

lubricating

Remove faults

Back to normal operation condition

Check before driving

Checking during driving

Check after driving

Replenish fuel, air,

coolant and electricity

Chapter 2 Vehicle Technical Maintenance

·53·

12. Check brake pad lining’s thickness;

13. Check and adjust manual brake devices;

14. Check tyre for pressure, wear or damage;

15. Check wheel lugs torque;

16. Check tyre tread depth.

cabin and

cargo body

17. Check door hinges and limit arms;

18. Check for any crack and loosening,

Electrical

system

19. Check performances of headlights, alarm lights, turning lights and horn;

20. Check and adjust headlight beams;

21. Check windshield wiper and washer, add fluid if necessary;

22. Check battery fluid level, add distilled water if necessary;

Road test 23. Check and test vehicle technical performance.

2.2.2 Requirements to First Level Maintenance

1. All exposed nuts and bolts at following units are complete, fastened and crack-free: engine FR/RR

suspensions, intake/exhaust manifolds, assisted exhaust brake system, heating and A/C systems, engine radiator,

tyres, propeller shaft, vehicle body, accessory brackets;

2. Steering arm, steering tie rod and brake controls operate well with complete fittings; no free plays on tie

rod ball joints, steering cross bearings and propeller shaft cross bearings;

3. Fluid levels of steering gear, transmission, transaxle should be 0-15mm under inspection doors (check

when engine is cold), vent hole should not be blocked; and flange nuts on transmission, final drive are fastened.

4. Lubricating fluid nozzles are complete and on their right mounting positions; all lubricating spots are fed

without being ignored,

5. Air filter element is clean and effective,

6. Tyre pressure is up to standard, no stone or other hard objects embedded in tyre.

7. Free travel of clutch and brake pedals comply with technical standards.

8. Lights, meters, horn and signals are complete and work well.

9. Battery fluid level is 10-15mm higher than plates, and battery vent hole unclogged and connectors

fastened.

10. No free play on wheel hub bearings,

11. Test run vehicle to check maintenance result. During test, there should be no abnormal noise on engine

and chassis, each control mechanism should meet technical demands; steering and braking system are sensitive

and reliable, and no loosening on fittings. After test run, check engine and chassis for oil, fluid, air and electricity

leakages.

2.2.3 Flow chart of 1

st

level maintenance

Flow chart of 1

st

level maintenance is indicated as follow:

OPERATION AND MAINTENANCE MANUAL FOR FOTON VIEW SERIES LIGHT BUS

·54·

Chart 2-2 Flow chart of 1

st

level maintenance

2.3 Second level maintenance

After being used for a longer period of time or mileage (30000km or 12 months), vehicle should be checked

and adjusted thoroughly to retrieval its safety, power and fuel economy. For these purpose, vehicle is required to

be serviced completely with Second Level maintenance. Second level maintenance mainly focuses on checks and

adjustments besides these have made during first level maintenance, it also dismantles tyres to check and rotate.

To avoid vehicle’s early damage, vehicle will be diagnosed and analyzed technically before starting this

maintenance, and additional services or repairs based on diagnosed results may be added to maintenance

procedures. Professional service technician performs 2

nd

level maintenance.

2.3.1 Vehicle’s Technical judgment before 2

nd

level maintenance

Before 2

nd

level maintenance, there should be checks both with instruments and manually. These checks will

diagnose possible faults and assass vehicle’s technical condition, so as to determine additional procedures to 2

nd

maintenance’s basic procedures.

Basic methods to assass vehicle’s technical condition:

1. To know how the vehicle is driving. Service technician will ask driver how the vehicle is running (includes

engine power, abnormal noise, steering and braking performance, and oil consumption).

2. Review vehicle’s technical records that include records on driving, maintenance, check/test, assembly

repair and minor repairs during maintenance cycles.

3. Analyze results from instrumental check/test and manual check to pinpoint faults.

2.3.2 Diagnosing procedures before 2

nd

level maintenance

1. Engine check and test: performances at acceleration and deceleration, and possible engine’s smoke

emission and leakage;

2. Power-train check and test: clutch performance, transmission internal coordination, sealing conditions of

transmission and final drive. And also check transmission and final drive’s working temperature, and check for

any abnormal noise in the system.

3. Brake system: performances of main brake system, parking brake system, exhaust assisted brake system.

And check systems for any leakage.

4. Steering system check/test: steering wheel free travel, system performance, and check for any leakage.

Workshop check

Service operation

Material and labor time calculation

F

ill

ou

t

tec

hn

ica

l

fil

es

Maintenance schedule

Process check

Finish check

Delivery

Chapter 2 Vehicle Technical Maintenance

·55·

5. Drive line system check/test: abnormal tyre wear, suspension bushes wear, and check bolts on body for

any loosening, rust and distort, also check body surface for corrosion and paint peel-offs.

6. Electrical devices check/test: dashboard gauges’ indication, oil pressure, coolant temperature, alternator

charging indication, A/C, and heating device’s operation.

Checking methods: with check/test equipment, vehicle tester and by experience.

2.3.3 Technical performance assassment and additional service before 2

nd

level maintenance

Basis for additional service Description to 2

nd

level maintenance, details see chart 2-3.

Chart 2-3. Basis for additional service procedures to 2

nd

level maintenance

Category

Location

Check results

Faults

Additional services

Poor valve seal

Adjust valve clearance,

grind valve

Piston ring wear, top and

side gap increase, piston

ring breakage;

Replace piston ring

Cylinder worn, large

clearance

between

pistons

and

cylinder

walls;

Check

and

measure

cylinder,

select

piston,

bore cylinder if necessary

Piston ring stuck, ring

bank broken

Replace ring and piston,

check cylinder

Piston head burnt, bore

scratched

Replace

piston

(adjust

advance

angle

of

injection), check cooling

system.

Larger fitting clearance

between

crankshaft

/connecting rod bearing,

abnormal sound

Remove to check, adjust

clearance,

check

crankshaft journal wear,

measure its roundness and

cylindrical.

Cut

if

necessary.

Worn-out camshaft and

its timing gear

remove to check camshaft

and timing gear

Larger fitting clearance

and

abnormal

sound

--piston, piston pin and

connecting rod cooper

bush

Remove

to

check

clearances among them,

replace if necessary

Low

oil

pressure,

abnormal sound due to

larger crankshaft bearing

clearance

Remove to check, repair if

necessary

instrument

al check

engine

1. Engine’s power is 75%

lower than rated value;

2. Cylinder pressure is 80%

lower than rated value.

3. Uneven

power

outputs

among cylinders;

4. Excessive crankshaft case

gas leakage
＞40L/min（1000r/min）
＞70L/min（2000r/min）
5. Vacuum value is low and

unstable;

6. Higher cylinder leakage,

air pressure drops up to 0.25

Mpa;

7. Oil consumption increases

(＞0.3L/100km);

8. Low oil pressure;

9. Piston top burnt, cylinder

scratched;

10. Crankshaft

bearing

whining;

11. Piston pin whining;

12. Cylinder knock;

13. Valve noise.

Larger valve clearance,

worn valve mechanism

Adjust valve clearance,

check valve mechanism,

repair

or

replace

if

necessary