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Q6. Give a reasoned opinion as to the accuracy of the following assertions:

a) Absence of oil grooves in the liner wall between the oil supply points results in increased wear of liner and rings.

b) ‘Timed lubrication’ has little merit,

c) The most suitable position of the oil supply point is immediately below the bottom piston ring with the piston at the top dead centre.

Q3. a) Define the following conditions relating to lubricating oil

(i) Oxidation

(ii) Emulsification

(iii) Acidity

b) Explain how each of the conditions in Q3 (a) is controlled by maintenance

c) Suggest possible consequences if the conditions in Q3 (a) change and no corrective action is taken

Q3. State, with reasons, THREE properties required for a cylinder lubricant for a main engine operating on HFO.

(b) Describe, with the aid of a sketches, an electronically controlled cylinder lubrication system, stating how the timing and quantity of cylinder lubricant is regulated and set.

Q8. Compare the desirable qualities of the lubricating oil selected for each of the following duties and give reasons for the differing properties of the oils recommended for these three purposes. (16)

a) Auxiliary diesel engines

b) Stern tube bearings

c) Refrigeration compressors

Q2. i) Explain using a simple line diagram difference between lubricating oil systems dealing with cylinder lubrication vis-à-vis crankcase lubrication. (7)

ii) State the properties of oil essential in each of these cases. (4)

iii) What is synthetic oil? How it is different from Mineral oil? Where is it used? (5)

Q2. i) Explain the purpose and applications of using lubricating oils on board. (8)

ii) Name the types of lubricating oil used on ships and mention various properties of same and their significance. (8)

Q9. (i) Discuss 'on board testing' of lubricating oil. What are the salient points for which lube oil testing is necessary? (4)

(ii) Name the test which are normally carried out and reasons for same. (4)

(iii) Name instruments used for measuring ‘viscosity' and 'flash point' Explain their, working principle (8)

Q4. With reference to lubricating oil:

(a) Explain why oil employed in the crankcase of a trunk piston engine differs in its properties from that employed in the crankcase of a crosshead engine. (6)

(b) List FOUR effects of bacterial attack on crankcase oil.

(c) Explain the action which must be taken if bacterial attack of the crankcase oil is detected. (4)

Q2. (a) Describe with suitable sketches, how lubricating oil is conveyed to top end, bottom end and main bearings in a large bore slow speed engine. (10)

(b) List the causes leading to sudden loss of lubricating oil pressure in the engine. (6)

Q8. a) Draw Lubricating oil piping diagram will all fittings for a trunk type 4- stroke Diesel Engine. (8)

b) What properties are required for a Lubricating oil used in a 4-stroke Diesel Engine? (4)

c) What is the effect on lubricating oil due to various contaminants during operation of engine? (4)

Q3) (a) With a diagram of the lubricating oil line, explain the working of an automatic backflushing filter placed on the lubricating oil line of the main engine. (10)

(b) List the main difference between such filter and a centrifugal separator. (6)

Q3. (a) Describe means of recognizing deterioration of the lubricating oil (8)

(b) Describe how lubrication oil is conveyed to top end, bottom end and main bearings in large bore, 2-stroke cross head type slow speed diesel engine, you are familiar with (8)