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10. What is meant by valve timing? What is the significance of valve timing? Explain it

briefly with the help of actual valve timing diagram and compare it with theoretical

valve timing diagram. (10)
11. Explain in detail the different types of mufflers used in SI engines. (10)
12. (a) Differentiate between forced and thermo-siphon cooling system (5)

(b) What are the disadvantages of overcooling? (5)
13. (a) What are the desirable properties of engine lubricating oil? (5)

(b) Explain the basic principle of lubrication. How will you determine the viscosity

index of lubricating oil? (5)
14. Explain the different types of oil pumps used in lubrication system. (10)
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