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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)

Q2.A. Explain how analysis of used lubricating oil can be used as a “health-monitoring” tool for diesel engines.

B. Describe how vibration measurement can be used with a main engine turbo-charger:

i. For fault analysis;

ii. For condition monitoring with respect to maintenance;

iii. As a substitute to opening up machinery for survey.

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)

Q7. A. State, with reasons, THREE properties required of crankcase oil which is to be used for a trunk piston main engine.

B. Explain how a representative sample of crankcase oil would be obtained from a trunk piston engine. C. Briefly describe the action to be taken if the crankcase oil charge cannot immediately be replaced and analysis shows – (i) Water is present; (ii) Alkalinity has fallen; (iii) Viscosity has changed appreciably; (iv) Carbon content has increased.

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. The analysis of oil may be used as a method of monitoring the condition of the equipment that it lubricates A. Explain briefly how shore analysts might test the oil; B. State the type of information that would be expected; C. Give possible reasons for an excess of: - i. Iron, ii. Copper, iii. Antimony Iv. Tin, v. Silica

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 bearing in large bore 2-stroke crosshead type slow speed diesel engine, you are familiar with (8)

Q9.  A report on the analysis of the main crosshead engine crankcase lubricating oil indicates the following contaminants or property changes. In EACH of the following cases give reasons for the possible causes of the contamination or property change, explaining how the actual cause would be detected; .

A. The presence of fresh water; B. White metal fragments; C. Reduced alkalinity reserve; D. Reduced anti oxidation reserve.

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 top dead centre.

Q1. With regard to the main turbine lubrication oil system:

a) (i) Describe the effects of tin oxide corrosion; (5)

(ii) Explain the actions to be taken if this occurs in a high-pressure turbine thrust bearing. (5)

b) Discuss the factors that determine the various filtration sizes: (6)