FOREWORD

Operation Manual Of C6121(SC11CB)

Series Diesel Engines

NO.121-SM-02+B

SHANGHAI DIESEL ENGINE CO., LTD.

January 2008FOREWORD

SDECs C6121(SC11CB) series diesel engines are the products that adopt 3300 series diesel engines technologies introduced from Caterpillar Inc. of America and had been produced under license from Caterpillar Inc. for 20 years by the end of 2007. To meet the need of users, this Manual is compiled and published which briefly describes operation and maintenance of the engine.

C121 series diesel engines are multi-purpose engines. It is possible, therefore, that the diagrams and illustrations given in this Manual differ from your engine for a specific application. Nevertheless, these diagrams and illustrations have their universality and thus can be referred to for proper use.

Since the design of the product is improved from time to time, the technical specifications shown in the Manual are subject to change without notice. Whenever a question arises regarding your engine or the Manual, please consult sales service center. When doing so, please indicate the model and date marked on the nameplate of your engine, so that you could be served better.

IMPORTANT SAFETY INFORMATION

To prevent accidental personal injury, all external rotating parts should be provided with protective guards and covers.

The engine must be stopped before the engine and its driving devices can be adjusted or repaired.

Do not wear loose clothing when working around the engine or machine.

During work in an enclosed shop, put on ear plugs to prevent hurt of hearing while the engine is running.

Wear protective glasses, work clothing, safety hats and other protective equipment when necessary.

Put on protective glasses and work clothing while cleaning with compressed air. The maximum air pressure should not exceed 205 kPa.

Do not smoke when refilling fuel, so as to avoid burning of fuel fumes.

Do not smoke when checking electrolyte level of a battery because the battery might emit flammable fumes.

Be sure there is proper ventilation in the shop where the engine operates.

Electrolyte is an acid. Avoid contact with your eyes and skin.

Do not attempt to do a repair which you do not understand. Read and comply with the Manual.

Make replacements or repairs to the maintenance and repair equipment with defects. Use appropriate tools.

Take off all tools, wires and other articles from the engine before it starts.

Wipe off any overflowing of lube oil, fuel oil, coolant and other liquids.

Make sure that there is an appropriate, safe and reliable way for disposal of waste oil.

Keep oily rags in a fireproof container. Do not place rags on the engine.

Do not leave any combustible liquids near the engine.

To prevent unexpected engine starting, disconnect the grounding wire of the batteries and insulate it with tapes before repairing the engine.

It is absolutely prohibited to start the engine when the speed control linkage of the governor is removed.

Before staring the engine which has been just repaired, be ready to cut off air supply so that the engine can be stopped as soon as it runs away after starting.

CONTENTS

Chapter One Main Technical Specifications1

I. General Engine Specifications1

1. Engine Design1

2. Main Engine Data2

3. Cylinder Block3

4. Cylinder Liner4

5. Cylinder Liner Projection4

6. Connecting Rod5

7. Timing Gears6

8. Valves8

9. Camshaft9

10. Valve Rocker Arms and Lifters10

11. Cylinder Head11

12. Valve Cover11

13. Pistons and Piston Rings12

14. Crankshaft, Main Bearings and Connecting Rod Bearings14

15. Run-Out of Flywheel17

16. Run-Out of Flywheel Housing18

17. Alternators20

18. Electric Starting Motor21

II. Description of Systems21

1. Fuel System21

2. Lubrication System22

3. Cooling System25

4. Wiring Diagram of Electric Starting26

III. Torque for Fasteners26

Chapter Two Operation and Adjustment29

I. Fuel, Oil and Coolant29

1. Fuel29

2. Lube Oil30

3. Coolant31

II. Engine Starting32

1. Inspections before Starting32

2. Electric Starting32

3. Applying Load after Starting33

III. Engine Stopping34

IV. Valve Lash Adjusting34

V. Checking Timing of Fuel Pump37

VI. Testing of Fuel Injection Nozzles39

1. Valves Opening Pressure Test41

2. Flushing the Nozzle42

3. Tip Leakage Test42

4. Orifice Restriction Test42

5. Bleed Screw Leakage Test43

VII. Checking Lubrication System44

1. Too Much Oil Consumption44

2. Oil Pressure Is Low44

3. Oil Pressure Is High45

4. Too Much Bearing Wear45

VIII. Belt Tension Adjustment46

Chapter Three Maintenance47

I.Maintenance As Needed47

II.Maintenance Every 10 Hours53

III.Maintenance Every 50 Hours54

IV.Maintenance Every 250 Hours55

V.Maintenance Every 500 Hours58

VI.Maintenance Every 1000 Hours58

VII.Maintenance Every 2000 Hours59

Chapter Four Troubleshooting60

Problem 1:Engine Will Not Turn When Start Switch Is On61

Problem 2:Engine Will Not Start61

Problem 3:Misfiring Or Running Rough62

Problem 4:Stall At Low R/Min62

Problem 5:Sudden Changes In Engine R/Min63

Problem 6:Not Enough Power63

Problem 7:Too Much Vibration64

Problem 8:Loud Combustion Noise (Knock)64

Problem 9:Loud Noise (Clicking) From Valve Compartment64

Problem 10:Oil In Cooling System65

Problem 11:Mechanical Noise (Knock) In Engine65

Problem 12:Fuel Consumption Too High65

Problem 13:Loud Noise From Valves Or Valve Operating Components65

Problem 14:Little Movement Of Rocker Arm And Too Much Valve Lash66

Problem 15:Valve Rotocoil Or Spring Lock Is Free66

Problem 16:Oil At The Exhaust66

Problem 17:Little Or No Valve Lash67

Problem 18:Engine Has Early Wear67

Problem 19:Coolant In Lubrication Oil67

Problem 20:Too Much Black Or Gray Smoke67

Problem 21:Too Much White Or Blue Smoke68

Problem 22:Engine Has Low Oil Pressure68

Problem 23:Engine Uses Too Much Lubrication Oil69

Problem 24:Engine Coolant Is Too Hot69

Problem 25:Starting Motor Does Not Turn70

Problem 26:Alternator Gives No Charge70

Problem 27:Alternator Charge Rate Is Low Or Not Regular70

Problem 28:Alternator Charge Is Too High71

Problem 29:Alternator Has Noise71

Problem 30:Exhaust Temperature Is Too High71