Syllabus For The Subject Machine Design

1. Introduction ...1–15

1. Definition. 2. Classifications of Machine Design.

3. General Considerations in Machine Design.

4. General Procedure in Machine Design.

5. Fundamental Units. 6. Derived Units. 7. System of

Units. 8. S.I Units (International System of Units).

9. Metre. 10. Kilogram. 11. Second. 12. Presentation

of Units and their values. 13. Rules for S.I. Units.

14. Mass and Weight. 15. Inertia. 16. Laws of Motion.

17. Force. 18. Absolute and Gravitational Units of

Force. 19. Moment of a Force. 20. Couple. 21. Mass

Density. 22. Mass Moment of Inertia. 23. Angular

Momentum. 24. Torque. 25. Work. 26. Power.

27. Energy.

2. Engineering Materials and Their Properties ...16–52

1. Introduction. 2. Classification of Engineering

Materials. 3. Selection of Materials for Engineering

Purposes. 4. Physical Properties of Metals.

5. Mechanical Properties of Metals. 6. Ferrous Metals.

7. Cast Iron. 8. Types of Cast Iron. 9. Alloy Cast Iron.

10. Effect of Impurities on Cast Iron. 11. Wrought Iron.

12. Steel. 13. Steels Designated on the Basis of

Mechanical Properties. 14. Steels Designated on the

Basis of Chemical Composition. 15. Effect of Impurities

on Steel. 16. Free Cutting Steels. 17. Alloy Steels.

18. Indian Standard Designation of Low and Medium

Alloy Steels. 19. Stainless Steel. 20. Heat Resisting

Steels. 21. Indian Standard Designation of High Alloy

Steels (Stainless Steel and Heat Resisting Steel).

22. High Speed Tool Steels. 23. Indian Standard

Designation of High Speed Tool Steel. 24. Spring Steels.

25. Heat Treatment of Steels. 26. Non-ferrous Metals.

27. Aluminium. 28. Aluminium Alloys. 29. Copper.

30. Copper Alloys. 31. Gun Metal. 32. Lead. 33. Tin.

34. Bearing Metals. 35. Zinc Base Alloys. 36. Nickel

Base Alloys. 37. Non-metallic Materials.



3. Manufacturing Considerations in Machine Design ...53–86

1. Introduction. 2. Manufacturing Processes.

3. Casting. 4. Casting Design. 5. Forging. 6. Forging

Design. 7. Mechanical Working of Metals. 8. Hot

Working. 9. Hot Working Processes. 10. Cold Working.

11. Cold Working Processes. 12. Interchangeability.

13. Important Terms Used in Limit System. 14. Fits.

15. Types of Fits. 16. Basis of Limit System. 17. Indian

Standard System of Limits and Fits. 18. Calculation of

Fundamental Deviation for Shafts. 19. Calculation of

Fundamental Deviation for Holes. 20. Surface

Roughness and its Measurement. 21. Preferred


4. Simple Stresses in Machine Parts ...87–119

1. Introduction. 2. Load. 3. Stress. 4. Strain. 5. Tensile

Stress and Strain. 6. Compressive Stress and Strain.

7. Young's Modulus or Modulus of Elasticity. 8. Shear

Stress and Strain 9. Shear Modulus or Modulus of

Rigidity. 10. Bearing Stress. 11. Stress-strain Diagram.

12. Working Stress. 13. Factor of Safety. 14. Selection

of Factor of Safety. 15. Stresses in Composite Bars.

16. Stresses Due to Change in Temperature—Thermal

Stresses. 17. Linear and Lateral Strain. 18. Poisson's

Ratio. 19. Volumetric Strain. 20. Bulk Modulus.

21. Relation Between Bulk Modulus and Young's

Modulus. 22. Relation Between Young's Modulus and

Modulus of Rigidity. 23. Impact Stress. 24. Resilience.

5. Torsional and Bending Stresses in Machine Parts ...120–180

1. Introduction. 2. Torsional Shear Stress. 3. Shafts in

Series and Parallel. 4. Bending Stress in Straight Beams.

5. Bending Stress in Curved Beams. 6. Principal Stresses

and Principal Planes. 7. Determination of Principal

Stresses for a Member Subjected to Bi-axial Stress.

8. Application of Principal Stresses in Designing

Machine Members. 9. Theories of Failure Under Static

Load. 10. Maximum Principal or Normal Stress Theory

(Rankine’s Theory). 11. Maximum Shear Stress Theory

(Guest’s or Tresca’s Theory). 12. Maximum Principal

Strain Theory (Saint Venant’s Theory). 13. Maximum

Strain Energy Theory (Haigh’s Theory). 14. Maximum

Distortion Energy Theory (Hencky and Von Mises

Theory). 15. Eccentric Loading—Direct and Bending

Stresses Combined. 16. Shear Stresses in Beams.


6. Variable Stresses in Machine Parts ...181–223

1. Introduction. 2. Completely Reversed or Cyclic

Stresses. 3. Fatigue and Endurance Limit. 4. Effect of

Loading on Endurance Limit—Load Factor. 5. Effect of

Surface Finish on Endurance Limit—Surface Finish

Factor. 6. Effect of Size on Endurance Limit—Size

Factor. 7. Effect of Miscellaneous Factors on Endurance

Limit. 8. Relation Between Endurance Limit and

Ultimate Tensile Strength. 9. Factor of Safety for Fatigue

Loading. 10. Stress Concentration. 11. Theoretical or

Form Stress Concentration Factor. 12. Stress

Concentration due to Holes and Notches. 13. Methods

of Reducing Stress Concentration. 14. Factors to be

Considered while Designing Machine Parts to Avoid

Fatigue Failure. 15. Stress Concentration Factor for

Various Machine Members. 16. Fatigue Stress

Concentration Factor. 17. Notch Sensitivity.

18. Combined Steady and Variable Stresses. 19. Gerber

Method for Combination of Stresses. 20. Goodman

Method for Combination of Stresses. 21. Soderberg

Method for Combination of Stresses. 22. Combined

Variable Normal Stress and Variable Shear Stress.

23. Application of Soderberg's Equation.

7. Pressure Vessels ...224–260

1. Introduction. 2. Classification of Pressure Vessels.

3. Stresses in a Thin Cylindrical Shell due to an Internal

Pressure. 4. Circumferential or Hoop Stress.

5. Longitudinal Stress. 6. Change in Dimensions of a

Thin Cylindrical Shell due to an Internal Pressure.

7. Thin Spherical Shells Subjected to an Internal

Pressure. 8. Change in Dimensions of a Thin Spherical

Shell due to an Internal Pressure. 9. Thick Cylindrical

Shell Subjected to an Internal Pressure. 10. Compound

Cylindrical Shells. 11. Stresses in Compound

Cylindrical Shells. 12. Cylinder Heads and Cover


8. Pipes and Pipe Joints ...261–280

1. Introduction. 2. Stresses in Pipes. 3. Design of Pipes.

4. Pipe Joints. 5. Standard Pipe Flanges for Steam.

6. Hydraulic Pipe Joint for High Pressures. 7. Design

of Circular Flanged Pipe Joint. 8. Design of Oval

Flanged Pipe Joint. 9. Design of Square Flanged Pipe



9. Riveted Joints ...281–340

1. Introduction. 2. Methods of Riveting. 3. Material of

Rivets. 4. Essential Qualities of a Rivet. 5. Manufacture

of Rivets. 6. Types of Rivet Heads. 7. Types of Riveted

Joints. 8. Lap Joint. 9. Butt Joint. 10. Important Terms

Used in Riveted Joints. 11. Caulking and Fullering.

12. Failures of a Riveted Joint. 13. Strength of a Riveted

Joint. 14. Efficiency of a Riveted Joint. 15. Design of

Boiler Joints. 16. Assumptions in Designing Boiler

Joints. 17. Design of Longitudinal Butt Joint for a Boiler.

18. Design of Circumferential Lap Joint for a Boiler.

19. Recommended Joints for Pressure Vessels.

20. Riveted Joint for Structural Use – Joints of Uniform

Strength (Lozenge Joint). 21. Eccentric Loaded Riveted


10. Welded Joints ...341–376

1. Introduction. 2. Advantages and Disadvantages of

Welded Joints over Riveted Joints. 3. Welding

Processes. 4. Fusion Welding. 5. Thermit Welding.

6. Gas Welding. 7. Electric Arc Welding. 8. Forge

Welding. 9. Types of Welded Joints. 10. Lap Joint.

11. Butt Joint. 12. Basic Weld Symbols.

13. Supplementary Weld Symbols. 14. Elements of a

Weld Symbol. 15. Standard Location of Elements of a

Welding Symbol. 16. Strength of Transverse Fillet

Welded Joints. 17. Strength of Parallel Fillet Welded

Joints. 18. Special Cases of Fillet Welded Joints.

19. Strength of Butt Joints. 20. Stresses for Welded

Joints. 21. Stress Concentration Factor for Welded

Joints. 22. Axially Loaded Unsymmetrical Welded

Sections. 23. Eccentrically Loaded Welded Joints.

24. Polar Moment of Inertia and Section Modulus of


11. Screwed Joints ...377–430

1. Introduction. 2. Advantages and Disadvantages of

Screwed Joints. 3. Important Terms used in Screw

Threads. 4. Forms of Screw Threads. 5. Location of

Screwed Joints. 6. Common Types of Screw Fastenings.

7. Locking Devices. 8. Designation of Screw Threads.

9. Standard Dimensions of Screw Threads. 10. Stresses

in Screwed Fastening due to Static Loading. 11. Initial

Stresses due to Screwing Up Forces. 12. Stresses due

to External Forces. 13. Stress due to Combined Forces.

14. Design of Cylinder Covers. 15. Boiler Stays.

16. Bolts of Uniform Strength. 17. Design of a Nut.


18. Bolted Joints under Eccentric Loading. 19. Eccentric

Load Acting Parallel to the Axis of Bolts. 20. Eccentric

Load Acting Perpendicular to the Axis of Bolts.

21. Eccentric Load on a Bracket with Circular Base.

22. Eccentric Load Acting in the Plane Containing the


12. Cotter and Knuckle Joints ...431–469

1. Introduction. 2. Types of Cotter Joints. 3. Socket

and Spigot Cotter Joint. 4. Design of Socket and Spigot

Cotter Joint. 5. Sleeve and Cotter Joint. 6. Design of

Sleeve and Cotter Joint. 7. Gib and Cotter Joint.

8. Design of Gib and Cotter Joint for Strap End of a

Connecting Rod. 9. Design of Gib and Cotter Joint for

Square Rods. 10. Design of Cotter Joint to Connect

Piston Rod and Crosshead. 11. Design of Cotter

Foundation Bolt. 12. Knuckle Joint.13. Dimensions of

Various Parts of the Knuckle Joint.14. Methods of

Failure of Knuckle Joint. 15. Design Procedure of

Knuckle Joint. 16. Adjustable Screwed Joint for Round

Rods (Turn Buckle). 17. Design of Turn Buckle.

13. Keys and Coupling ...470–508

1. Introduction. 2. Types of Keys. 3. Sunk Keys.

4. Saddle Keys. 5. Tangent Keys. 6. Round Keys.

7. Splines. 8. Forces acting on a Sunk Key. 9. Strength

of a Sunk Key. 10. Effect of Keyways. 11. Shaft

Couplings. 12. Requirements of a Good Shaft Coupling.

13. Types of Shaft Couplings. 14. Sleeve or Muff

Coupling. 15. Clamp or Compression Coupling.

16. Flange Coupling. 17. Design of Flange Coupling.

18. Flexible Coupling. 19. Bushed Pin Flexible

Coupling. 20. Oldham Coupling. 21. Universal


14. Shafts ...509–557

1. Introduction. 2. Material Used for Shafts.

3. Manufacturing of Shafts. 4. Types of Shafts.

5. Standard Sizes of Transmission Shafts. 6. Stresses in

Shafts. 7. Maximum Permissible Working Stresses for

Transmission Shafts. 8. Design of Shafts. 9. Shafts

Subjected to Twisting Moment Only. 10. Shafts

Subjected to Bending Moment Only. 11. Shafts

Subjected to Combined Twisting Moment and Bending

Moment. 12. Shafts Subjected to Fluctuating Loads.

13. Shafts Subjected to Axial Load in addition to

Combined Torsion and Bending Loads. 14. Design of

Shafts on the Basis of Rigidity.


15. Levers ...558–599

1. Introduction. 2. Application of Levers in Engineering

Practice. 3. Design of a Lever. 4. Hand Levers. 5. Foot

Lever. 6. Cranked Lever. 7. Lever for a Lever Safety

Valve. 8. Bell Crank Lever. 9. Rocker Arm for Exhaust

Valve. 10. Miscellaneous Levers.

16. Columns and Struts ...600–623

1. Introduction. 2. Failure of a Column or Strut. 3. Types

of End Conditions of Columns. 4. Euler’s Column

Theory. 5. Assumptions in Euler’s Column Theory.

6. Euler’s Formula. 7. Slenderness Ratio. 8. Limitations

of Euler’s Formula. 9. Equivalent Length of a Column.

10. Rankine’s Formula for Columns. 11. Johnson’s

Formula for Columns. 12. Long Columns Subjected to

Eccentric Loading. 13. Design of Piston Rod. 14. Design

of Push Rods. 15. Design of Connecting Rod. 16. Forces

Acting on a Connecting Rod.

17. Power Screws ...624–676

1. Introduction. 2. Types of Screw Threads used for

Power Screws. 3. Multiple Threads. 4. Torque Required

to Raise Load by Square Threaded Screws. 5. Torque

Required to Lower Load by Square Threaded Screws.

6. Efficiency of Square Threaded Screws. 7. Maximum

Efficiency of Square Threaded Screws. 8. Efficiency vs.

Helix Angle. 9. Overhauling and Self-locking Screws.

10. Efficiency of Self Locking Screws. 11. Coefficient

of Friction. 12. Acme or Trapezoidal Threads.

13. Stresses in Power Screws. 14. Design of Screw Jack.

15. Differential and Compound Screws.

18. Flat Belt Drives ...677–714

1. Introduction. 2. Selection of a Belt Drive. 3. Types

of Belt Drives. 4. Types of Belts. 5. Material used for

Belts. 6. Working Stresses in Belts. 7. Density of Belt

Materials. 8. Belt Speed. 9. Coefficient of Friction

Between Belt and Pulley 10. Standard Belt Thicknesses

and Widths. 11. Belt Joints. 12. Types of Flat Belt

Drives. 13. Velocity Ratio of a Belt Drive. 14. Slip of

the Belt. 15. Creep of Belt. 16. Length of an Open Belt

Drive. 17. Length of a Cross Belt Drive. 18. Power

transmitted by a Belt. 19. Ratio of Driving Tensions for

Flat Belt Drive. 20. Centrifugal Tension. 21. Maximum

Tension in the Belt. 22. Condition for Transmission of

Maximum Power. 23. Initial Tension in the Belt.


19. Flat Belt Pulleys ...715–726

1. Introduction. 2. Types of Pulleys for Flat Belts.

3. Cast Iron Pulleys. 4. Steel Pulleys. 5. Wooden

Pulleys. 6. Paper Pulleys. 7. Fast and Loose Pulleys.

8. Design of Cast Iron Pulleys.

20. V-Belt and Rope Drives ...727–758

1. Introduction. 2. Types of V-belts and Pulleys.

3. Standard Pitch Lengths of V-belts. 4. Advantages and

Disadvantages of V-belt Drive over Flat Belt Drive.

5. Ratio of Driving Tensions for V-belt. 6. V-flat Drives.

7. Rope Drives. 8. Fibre Ropes. 9. Advantages of Fibre

Rope Drives. 10. Sheave for Fibre Ropes. 11. Ratio of

Driving Tensions for Fibre Rope. 12. Wire Ropes.

13. Advantages of Wire Ropes. 14. Construction of

Wire Ropes. 15. Classification of Wire Ropes.

16. Designation of Wire Ropes. 17. Properties of Wire

Ropes. 18. Diameter of Wire and Area of Wire

Rope.19. Factor of Safety for Wire Ropes.20. Wire Rope

Sheaves and Drums. 21. Wire Rope Fasteners.

22. Stresses in Wire Ropes. 23. Procedure for Designing

a Wire Rope.

21. Chain Drives ...759–775

1. Introduction. 2. Advantages and Disadvantages of

Chain Drive over Belt or Rope Drive. 3. Terms Used

in Chain Drive. 4. Relation Between Pitch and Pitch

Circle Diameter. 5. Velocity Ratio of Chain Drives.

6. Length of Chain and Centre Distance.

7. Classification of Chains. 8. Hoisting and Hauling

Chains. 9. Conveyor Chains. 10. Power Transmitting

Chains. 11. Characteristics of Roller Chains. 12. Factor

of Safety for Chain Drives. 13. Permissible Speed of

Smaller Sprocket. 14. Power Transmitted by Chains.

15. Number of Teeth on the Smaller or Driving Sprocket

or Pinion. 16. Maximum Speed for Chains.

17. Principal Dimensions of Tooth Profile. 18. Design

Procedure for Chain Drive.

22. Flywheel ...776–819

1. Introduction. 2. Coefficient of Fluctuation of Speed.

3. Fluctuation of Energy. 4. Maximum Fluctuation of

Energy. 5. Coefficient of Fluctuation of Energy.

6. Energy Stored in a Flywheel. 7. Stresses in a Flywheel

Rim. 8. Stresses in Flywheel Arms. 9. Design of

Flywheel Arms. 10. Design of Shaft, Hub and Key.

11. Construction of Flywheels.


23. Springs ...820–884

1. Introduction. 2. Types of Springs. 3. Material for

Helical Springs. 4. Standard Size of Spring Wire.

5. Terms used in Compression Springs. 6. End

Connections for Compression Helical Springs. 7. End

Connections for Tension Helical Springs. 8. Stresses

in Helical Springs of Circular Wire. 9. Deflection of

Helical Springs of Circular Wire. 10. Eccentric Loading

of Springs. 11. Buckling of Compression Springs.

12. Surge in Springs. 13. Energy Stored in Helical

Springs of Circular Wire. 14. Stress and Deflection in

Helical Springs of Non-circular Wire. 15. Helical

Springs Subjected to Fatigue Loading. 16. Springs in

Series. 17. Springs in Parallel. 18. Concentric or

Composite Springs. 19. Helical Torsion Springs.

20. Flat Spiral Springs. 21. Leaf Springs.

22. Construction of Leaf Springs. 23. Equalised Stresses

in Spring Leaves (Nipping). 24. Length of Leaf Spring

Leaves. 25. Standard Sizes of Automobile Suspension

Springs. 26. Material for Leaf Springs.

24. Clutchces ...885–916

1. Introduction. 2. Types of Clutches. 3. Positive

Clutches. 4. Friction Clutches. 5. Material for Friction

Surfaces. 6. Considerations in Designing a Friction

Clutch. 7. Types of Friction Clutches. 8. Single Disc or

Plate Clutch. 9. Design of a Disc or Plate Clutch.

10. Multiple Disc Clutch. 11. Cone Clutch. 12. Design

of a Cone Clutch. 13. Centrifugal Clutch. 14. Design

of a Centrifugal Clutch.

25. Brakes ...917–961

1. Introduction. 2. Energy Absorbed by a Brake. 3. Heat

to be Dissipated during Braking. 4. Materials for Brake

Lining. 5. Types of Brakes. 6. Single Block or Shoe

Brake. 7. Pivoted Block or Shoe Brake. 8. Double Block

or Shoe Brake. 9. Simple Band Brake. 10. Differential

Band Brake. 11. Band and Block Brake. 12. Internal

Expanding Brake.

26. Sliding Contact Bearings ...962–995

1. Introduction.2. Classification of Bearings. 3. Types

of Sliding Contact Bearings.4. Hydrodynamic

Lubricated Bearings. 5. Assumptions in Hydrodynamic

Lubricated Bearings. 6. Important Factors for the

Formation of Thick Oil Film in Hydrodynamic

Lubricated Bearings. 7. Wedge Film Journal Bearings.

8. Squeeze Film Journal Bearings. 9. Properties of

Sliding Contact Bearing Materials.10. Materials used

for Sliding Contact Bearings.11. Lubricants.


12. Properties of Lubricants.13. Terms used in

Hydrodynamic Journal Bearings.14. Bearing

Characteristic Number and Bearing Modulus for

Journal Bearings. 15. Coefficient of Friction for Journal

Bearings.16. Critical Pressure of the Journal Bearing.

17. Sommerfeld Number. 18. Heat Generated in a

Journal Bearing. 19. Design Procedure for Journal

Bearings. 20. Solid Journal Bearing. 21. Bushed

Bearing. 22. Split Bearing or Plummer Block.

23. Design of Bearing Caps and Bolts. 24. Oil Grooves.

25. Thrust Bearings. 26. Foot-step or Pivot Bearings.

27. Collar Bearings.

27. Rolling Contact Bearings ...996–1020

1. Introduction. 2. Advantages and Disadvantages of

Rolling Contact Bearings Over Sliding Contact

Bearings. 3. Types of Rolling Contact Bearings. 4. Types

of Radial Ball Bearings. 5. Standard Dimensions and

Designation of Ball Bearings. 6. Thrust Ball Bearings.

7. Types of Roller Bearings. 8. Basic Static Load Rating

of Rolling Contact Bearings. 9. Static Equivalent Load

for Rolling Contact Bearings. 10. Life of a Bearing.

11. Basic Dynamic Load Rating of Rolling Contact

Bearings. 12. Dynamic Equivalent Load for Rolling

Contact Bearings. 13. Dynamic Load Rating for Rolling

Contact Bearings under Variable Loads. 14. Reliability

of a Bearing. 15. Selection of Radial Ball Bearings.

16. Materials and Manufacture of Ball and Roller

Bearings. 17. Lubrication of Ball and Roller Bearings.

28. Spur Gears ...1021–1065

1. Introduction. 2. Friction Wheels. 3. Advantages and

Disadvantages of Gear Drives. 4. Classification of

Gears.5. Terms used in Gears. 6. Condition for Constant

Velocity Ratio of Gears–Law of Gearing. 7. Forms of

Teeth. 8. Cycloidal Teeth. 9. Involute Teeth.

10. Comparison Between Involute and Cycloidal

Gears.11. Systems of Gear Teeth.12. Standard

Proportions of Gear Systems.13. Interference in

Involute Gears.14. Minimum Number of Teeth on the

Pinion in order to Avoid Interference.15. Gear

Materials. 16. Design Considerations for a Gear

Drive.17. Beam Strength of Gear Teeth-Lewis Equation.

18. Permissible Working Stress for Gear Teeth in Lewis

Equation. 19. Dynamic Tooth Load. 20. Static Tooth

Load. 21. Wear Tooth Load. 22. Causes of Gear Tooth

Failure. 23. Design Procedure for Spur Gears.

24. Spur Gear Construction. 25. Design of Shaft for

Spur Gears. 26. Design of Arms for Spur Gears.


29. Helical Gears ...1066–1079

1. Introduction. 2. Terms used in Helical Gears. 3. Face

Width of Helical Gears. 4. Formative or Equivalent

Number of Teeth for Helical Gears. 5. Proportions for

Helical Gears. 6. Strength of Helical Gears.

30. Bevel Gears ...1080–1100

1. Introduction. 2. Classification of Bevel Gears.

3. Terms used in Bevel Gears. 4. Determination of Pitch

Angle for Bevel Gears. 5. Proportions for Bevel Gears.

6. Formative or Equivalent Number of Teeth for Bevel

Gears—Tredgold's Approximation. 7. Strength of Bevel

Gears. 8. Forces Acting on a Bevel Gear. 9. Design of

a Shaft for Bevel Gears.

31. Worm Gears ...1101–1124

1. Introduction 2. Types of Worms 3. Types of Worm

Gears. 4. Terms used in Worm Gearing. 5. Proportions

for Worms. 6. Proportions for Worm Gears.

7. Efficiency of Worm Gearing. 8. Strength of Worm

Gear Teeth. 9. Wear Tooth Load for Worm Gear.

10. Thermal Rating of Worm Gearing. 11. Forces

Acting on Worm Gears. 12. Design of Worm Gearing.

32. Internal Combustion Engine Parts ...1125–1214

1. Introduction. 2. Principal Parts of an I. C. Engine.

3. Cylinder and Cylinder Liner. 4. Design of a Cylinder.

5. Piston. 6. Design Considerations for a Piston.

7. Material for Pistons. 8. Pistion Head or Crown .

9. Piston Rings. 10. Piston Skirt. 12. Piston Pin.

13. Connecting Rod. 14. Forces Acting on the

Connecting Rod. 15. Design of Connecting Rod.

16. Crankshaft. 17. Material and Manufacture of

Crankshafts. 18. Bearing Pressure and Stresses in

Crankshfts. 19. Design Procedure for Crankshaft.

20. Design for Centre Crankshaft. 21. Side or Overhung

Chankshaft. 22. Valve Gear Mechanism. 23. Valves.

24. Rocker Arm. Protection Status