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Q3. Sketch and describe the arrangement of a main engine camshaft chain. Describe the repair procedure following fracture of one chain link during operation of the engine. Give possible reasons for the failure and explain how the chain is set initially at the correct degree of tension. (16)

Q6. Briefly explain the following:

(a) How would you know if a refrigeration system is 'undercharged'? (4)

(b) What should you do to ensure that there is no water leakage into the engine cylinder before preparing main engine for sea? (4)

(c) What would be the probable cause of a rise in the level of the lub oil sump tank of a main engine? (4)

(d) How does the valve rotator as fitted on an exhaust valve of aux. engine work? (4)

Q8. How are large slow speed engines structured to withstand the following forces?

A. Forces due to combustion load;

B. Guide forces;

C. Inertia forces.

Q9. (a) Describe how it is determined whether a crankshaft was twisted during a major “smash up” in a main engine. (4)

(b) Explain where twisting is most likely to occur. (4)

(c) Specify with reasons the degree of twisting that might be accommodated without correction (4)

(d) Explain briefly what adjustments and precautions should be instituted when putting an engine with a twisted crankshaft back into service. (4)

Q2. With respect to a 2- stroke main propulsion diesel engine draw and explain the following

a) How the various sections of exhaust manifold connected together for the main engine?

b) What is the arrangement for thermal expansion of different sections of the manifold?

c) What is the arrangement in the exhaust manifold to prevent broken pieces of piston rings entering turbine of the T/C? (16)

Q7. Evaluate the influence of the following factors upon cylinder and piston ring wear rates. (16)

A. Position of rings in relation to piston crown.

B. Spread and proximity of coolant passages from liner wall.

C. Flow rate and specific heat of coolant.

D. Chromium plating of ring faces.

Q8. What is a “Cam"? Explain its function. With reference to its application in diesel engines

Discuss the requirement and the type of cam used in

a) Fuel Pump

b) Indicator drive

c) Inlet Valve

d) Exhaust Valve

e) Starting air distributor. (16)

Q3. Why is it necessary to cool the cylinder head covers and cylinder liners and pistons of slow and medium speed engines? What are the different cooling mediums used for cooling slow and medium speed Engines explain with reasons? (16)

Q3. Recent experience has shown persistence damage occurring on seating faces of main engine exhaust valve, which is not confined to any particular unit.

(a) State with reason the possible causes. (6)

(b) State the short-term action to be taken in order to minimize engine operational problem. (5)

(c) State with reason how future incident of this nature could be minimized. (5)

Q8. (a) With an aid of a sketch briefly describe the important structural parts of 2-Stroke main Engine? How are different structural parts held together? (10)

(b) What is the function of Cross Head Guides? (6)