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Wednesday 5 March 2014

2s & 4S difference

Comparison between two stroke cycle diesel engine and a four stroke engine




Marine diesel engine guideline


The main difference between the two cycles is the power developed.
The two-stroke cycle engine, with one working or power stroke every revolution, will, theoretically, develop twice the power of a four-stroke engine of the same swept volume.
Inefficient scavenging however and other losses, reduce the power advantage .

Comparison between two stroke cycle diesel engine and a four stroke engine




Marine diesel engine guideline


The main difference between the two cycles is the power developed. The two-stroke cycle engine, with one working or power stroke every revolution, will, theoretically, develop twice the power of a four-stroke engine of the same swept volume. Inefficient scavenging however and other losses, reduce the power advantage .


For a particular engine power the two-stroke engine will be considerably lighter—an important consideration for ships. Nor does the two-stroke engine require the complicated valve operating mechanism of the four-stroke. The four-stroke engine however can operate efficiently at high speeds which offsets its power disadvantage; it also consumes less lubricating oil.

Each type of engine has its applications which on board ship have resulted in the slow speed (i.e. 80— 100 rev/min) main propulsion diesel operating on the two-stroke cycle. At this low speed the engine requires no reduction gearbox between it and the propeller. The four-stroke engine (usually rotating at medium speed, between 250 and 750 rev/ min) is used for auxiliaries such as alternators and sometimes for main propulsion with a gearbox to provide a propeller speed of between 80 and 100 rev/min.



Motor - orals


ME Alarms and trip- jcw, lo, pco, cyl oil, spring air, safety air, control air, t/c oil, fo low pr, cam shaft lo pr,
scavenge air ht, exhaust ht,
1.Exhaust temp of one unit is high; what could be the reason? Leaky injector,leaky exhaust valve,scavenge
fire,incorrect fuel injection timing,incorrect fuel pump setting,scavenge ports choked, temp indicator faulty.
2. How is L.O. For X head lubrication delivered in (B/W SULZER Engines)separate pipe fron m\e sump in
BNW and separate crosshead pump for sulzer engines.
3. How many the rods will be there? Function of tie rods?funtion pf tie rods is to hold the cylinder block,
engine frame and bed plate under compression. 2N+2
4. What is the role of the Thrust block? The role of thrust block is to transmit the axial thrust from the
propeller to the hull to avoid misalignment of crankshaft
5. Where is the thrust bearing in MC series or RTA engines’? in MC series engines thrist block is placed
after the flywheel.
6. Why is the thrust bearing at the aft end of the engine and not at the forward end? in the aft end to take the
axial thrust from propeller. Correct location of crankpin wrt centre of cyl.
7. Why is the thrust bearing close to the engine and close to the stern tube? Area near stern tube small and
nt adequately stiffened.
8. M/E stuffing box components? Housing, 4 part scrapper, 8 part sealing, 4 part sealing, 8 part sealing,
nitrile rubber rings, garter springs, diaphragm
9. What is the role of the stuffing box? Isolate crankcase from combustion chamber, avoid mixing of oils,
avoid combustion products goin to c/c
10. What is the difference between stuffing box drain oil and scavenge space drain oil? Scavenge space
drain oil is cyl oil. Stuffing box drain oil is c/c oil.
11. Why are piston rings changed? Excessive wearing, broken, avoid blow past, proper sealing.
12.stroke Valve timing diagram
13. What are the strokes in 2 stroke and four stroke engines? Compression/ expansion stroke.
Suction/compression/power/exhaust.
14. Why are telescopic pipes used for oil lubrication? For X hd lubrication.
15. Why is fuel timing important? Efficient combustion, avoid fuel knock, maximum power output, avoid
after burning.
16. How is checked and adjusted? (engine type based on candidate’s experience) changing relative angular
position of cam peak to crankshaft, raising plunger wrt follower, raising or lowering the casing.
17. What is the principle of a diesel engine? Dual cycle.
18. Why are 2 springs sometimes used in inlet and exhaust valves? Avoid breaking or bending due to
Resonance, one right hand and other left hand, twisting moment neutralized, increase closing force on
valve, avoid valve bounce.
19. What will you check in springs during overhaul? Dropping from a height, compress on a vice
20. I-low does a roto-cap work?
21. How is BHP calculation using indicator diagram done?
22. What is MEP and MIP? Mean effective pressure, mean indicated pressure.
23. What is the difference between the two
24. Why is cylinder head fitted in engines house the cyl hd mountings, provide an enclosed combustion
chamber, take compression and gas load.
25. Are there engines w/o cylinder head? Yes, double acting doxford 2 stroke opposed piston engines.
26. Draw 2s timing diagram
27. Why is an expansion tank provided in jacket cooling water system? Air removal, replenishing water,
expansion of hot liquid, positives suction head for pump.
28. Why do we Blow through’ Engines? To avoid water hammer.
29. How is T/C RPM measured? Proximity sensor
30. Is there any difference between A/E and M/E Governors a/e governor- load dependent constant speed
covernor, m/e governor- speed dependent variable speed.
31. Indicator cards why and and how are they taken? Me performance,
32. What is Hydrodynamic lubrication? Wedge of liquid is formed due to rotation, moving surfaces
separated by pr of continuous unbroken film of lub. Load taken completely by oil film.
33. What is rolling contact bearing? Ball or roller bearings
34. What is MCR and CSR? Maximum continuous rating- max continuous output at which engine can be
run safely and continuously, used for calculation of strength of engine. CSR- continuous standard ratingoutput
at service speed for economical and efficient operation corresponding to thermal and mechanical
load. Maintenance point of view
35. What is PS? What is its relation to kilowatt? PS german unit for horse power. 1 PS = 0.7355 KW =
0.986 hp
36. What was the specific fuel consumption in your last ship? 171 +- 5% @ mcr
37. What was the specific cylinder oil consumption? Cylinder oil consumption in grams per KwHr.
38. What is relation between power and rpm of a main diesel engine? Direct proportionality.
39. What will be the power developed by a main engine if it runs in DD? Bhp is generated but Tp and Ep
wud be 0.
40. What is the relation between the ship’s speed and engine power?
41. Will the engine develop any power, if it is run when a ship is aground? yes
42. What is a CPP? How does it function’? controllable pitch propeller,
43. What is the difference between fuel valve opening pressure and fuel injection pressure?
44. What is an under slung crankshaft? Supported from top, having springs on axles below. Low cog.
45. How many crankshafts are there in “V” type engines? one
46. How are connecting rods fitted?
47.Do two stroke engines need tappet clearance adjustment? no
48. How will you know, without opening anything, that an engine is 2S or 4S?
49. What are the two strokes in 2S engines called? Compression, power
50. Why does Sulzer use hydraulic jack bolts for main bearings?
51. What is the meaning of TBN in lubricating oils?
52. Why is LO of different TBN used for M/E cylinder oil and Crankcase oil’?
53. What are the valves of TBN for main engine crankcase oil? 8-10 for c/c oil, 70-80 cyl oil, trunk piston-
30-40
54. What is the difference between “heat” and “temperature”? heat is a form of energy. Temp is the degree
of hotness or coolness of the body
55. If water is found in crank case lo, what could be the cause? Liner leakage, purifier not efficient,
56.How will you test the opening pressure of a crank case relief door? Relief valve assembly removed from
place and fitted to a blank flange with connections for compressed air and pr. Gauge. Comp air then
admitted slowly to check lifting pr,
57.Sketch stern tube lubricating oil system. Type of seal arrangements to prevent lubricating oil going
overboard/sea water coming in. lip seal, stuffing box, radial face seals
58. How and why are tappet clearances taken?
59. What will you check in crane case inspection? Crankshaft deflection, metal particles in oil, smell and
colour of oil, paint peeling off, scoring on piston rod, black oil underside of stuffing box, web slippage,
bearing metal oozing out from casing, oil flowing from all lubricating points, crankcase vents clear,
connecting rod playgeneral inspection for any cracks.
60. State the starting interlocks on Main Engine. Turning gear interlock, running direction interlocks, cam
position interlock, telegraph interlock
61. How will you commission Aux. Engine (Generator) after its decarbonization?
62. How will you draw out lubricating samples for analysis and what information is require to he furnished
to laboratory? After filters when engine is still running. Running hours, machinery, original grade of oil.
63. If a piston has suffered damage/crack, how is the main Engine Unit out off?
64. How will you remove Main Bearing bottom half of Main Engine and also push back?
65. How is poker gauge reading taken and what is its significance? To measure propeller drop.
66. What is Impressed current system? Where is it fitted ? What is its purpose? How does it work?
67. What checks are carried out on Tall Shaft? Bending, resin grease on flange between tail and
intermediate shaft, cracks, alignment, grooving in way of seals, shaft grounding votage.
68. How will you proceed to take crankshaft deflections? What could possibly he reasons for crankshaft
misalignment? Bearing wear down, saddle wear, grounding, distortion of bed plate, uneven loading,
prolonged low load operation, slak foundation bolts, improper loading and ballasting
69. State your main engine specifications. in line 6 cyl,super long stroke, 600 mm bore dia, 2000 mm stoke
length, turbocharged, 11500 kw @ 97 rpm, cam operated
70. What action will you take if Main Engine Piston is about to seize? Increase cylinder lub and keep
turning on turning gear.
71. Setting pressure of crankcase relief valve? Relationship between area of relief valve and volume of
crankcase. Aggregate area of all valves to be 115 cm2 per m3 crank case volume.0.2 bar. Fiteed for engines
more than 200mm bore or 0.6 m3 cc volume. 200-250- 1 at each end, 1 more if more than 8 cyl, 250-300-
one at each alternate crank throw, minimum 2, >300- one in each crank throw. One in chain case.
72. What is the difference between Main Engine and Aux. Engine Governor?
73. How will you reverse the the engine from full ahead/full astern/ crash stop?
74. When blowing through main engine, one of the units relief valve is lifted. What could be the reasons?
Indicator cock shut and water inside.
75. Why does a Piston seize? What action must be taken? Cylinder lubrication inadequate, micro seizure.
76. What will you check if piston cooling and jacket cooling temperatures start going high? Preheat setting,
jcw temperature controller, purge oil from controller, lt cooling temp high.
77. What are the symptoms of piston crack and liner crack? What action will you take? Rapid rise in sump
level, piston cooling temperature high.
78. What is athwart ship4? Port starboard
79. What is name Thrust Block and what is its purpose and where is it fitted?
80. What is the name of big end Bearing Bolts?
81. Give reasons for main engine not starting on air. Starting air pr low, v/v on start air bottle closed, valve
to star air distributor closed, main air block valve closed, turning gear engaged, pistons in distributor
sticking, distributor wrongly adjusted, sticking control valve of distributor, cylinder air start valve
defective, no control air, in cpp control air blades not on zero pitch.
82. What is Compression pressure in main engine? 100-110 bar
83. What is the first symptom of Scavenge fire? Increase in scavenge air temperature, increased exhaust
temp, surging, smoke from t/c air inlet, smoke, noise
84. Why do we measure Butt clearance? To maintain the specified clearance
85. What is the use of telegraph? Communication device.
86. State maximum and minimum clearances of Butt clearance. 0.5% to 1% of bore diameter.
87. Describe safety features of a main engine. Cylinder head relief valve, crankcase relief valve, oil mist
detector, scavenge air high temp. alarm, bearing high temp alarm,bursting disc in starting air line
88. State remedial measures of a Scavenge fire. in small fire continue to run engine, cut off fuel to affected
unit, inc cyl oil, keep clear of scavenge door, check parameters, if large fires reduce speed stop engine,
auxiliary blower off, t\c inlet covered, fuel oil shut off, scavenge drains closed, cyl lube shut, introduce
fixed fire fighting, boundry cooling,when temp low enogh , enter ,clean, find outcause and rectify.
89. What is diesel knock and how does it affect engine performance? Combustion noise due to ignition
delay, occurs during starting from cold. Rapid increase in pressure and temperature, after burning,
uneconomic running.
90. What is after burning and what are its symptoms? Exhaust temp high, uneconomic running, reduction in
thermal efficiency, loss of power, fouling from carbon deposits, overheating in exhaust system.
91. What are the types of Scavenging’? loop, cross, uniflow
92. What will you do if jacket temperature of Auxi. Engine increases in the watch? Change over jacket
water cooler or put both coolers in service.
93. How do you come to know an exhaust valve is leaking in any cylinder’? high exhaust temperature, loss
of compression pressure, spark from funnel,
94. How do we know if an air inlet is leaking? Starting air line will be hot, relief valve/ bursting disc will
lift
95. What is the requirement of a crosshead? take the axial thrust exerted by the connecting rod and transmit
it to A frame.
96. How is an engine installed on a tanktop? Holding down bolts, side and bottom chocks.
97. What is scavenge fire? Causes, Prevention and action taken?
98. What is crankcase explosion? Causes, Prevention and action taken?
99. To what pressure is a crankcase relief door valve set and how does it function? 0.2 bar.
100. During manoeuvring if automatic air starting valve gets seized, what action will you take? in one
deign I t can be operated by hand by engaging a clutch on a collar on the valve spindle, in another design
auto valve operated by hand wheel can be set to three position, positively shut, positively open and auto
operation.
101. What have you gained from the Simulation Course attended by you?
102. What is the safety out simulator?
103. From where we do the crash manoeuvring? Engine control room or local control station.
104. How is an AE decarbonised?
105. What precaution will you take while increasing oil scraper ring in piston groove and why?
106. How do you start a generator’?
107.How to start a purifier and stop it? Fill operating water tank, open steam to heater, start motor, wait till
amperage drops to normal. manual starting...first run the px motor...then supply the bowl closing water for
10 sec...then supply seal water till u see it coming out of sludge port. then supply bowl opening water for 2
sec...then supply closing water again...supply supply water ....confirm no leakage from bowl....then start the
feed of oil
108. State the symptoms at of piston running hot. Piston cooling oil outlet temp high
109. If thrust bearing lubricating oil temp. is getting higher, what action will be taken by you? Check flow
of oil, put a gunny cloth soaked with water on it a s an emergency measure,reducing speed not advisable
because less speed less lubrication.if possible inform bridge and stop engines asap. investigate the sourse of
high temperature and rectify...mostly it is due to failure of lubrication or damage to bearings
110. What is the purpose of clutch pad in a purifier?
111. What are the probable cause of H.O And L. 0. Purifier Overflow? Throughput high, sludge deposits,
sealing water low, improper gravity disc.
112. If generator sump is rising what a probable cause and action you will take? Contamination by f/o
water or cyl oil.
113. When are safety cut outs of Main Engine tried out and how often?
114. What is the effect of a gravity disc on the separation in a purifier?creates a back pressure in the oil
thus maintaining the intrephase within the disc stack’
115. Principle and operation of remote level indicating gauges. Electric/ pneumatic
116. What is a micrometer gauge?
117. Procedure for removing a Main Bearing and taking clearances.
118. How is thrust clearances measured? Pad and pad, pad and collar, pad and stopper. 0.5 to 1.0, 1.5 max,
5mm between thrust pad and stopper.
119.How is an indicator Card Diagram taken? Power card- drum in phase with piston movement.
Compression card- drum in phase, fuel cut off, out of phase dia- drum 90 deg out of phase, light spring diain
phase with a light comp spring.
120. Bunkering Procedure.
121. Why does surging take place in Turbo charger? Reduction in load, back pressure wave.
122. How is a fuel injector tested onboard? Fuel injector test kit.
123. Methods of starting.
124. Describe lubricating systems of Main Engine and Aux. Engine.
125. Define mechanical efficiency, brake power, thermal efficiency. Mechanical eff = brake power/
indicated power. Brake power is the power available at the flywheel measured by dynamometer. Thermal
efficiency = heat converted into work / heat added.
126. What are the starting precautions taken for AE?
127. Difference between 2-S and 4-S.
128. Crankcase explosion.
129. Spark coming from funnel. Exhaust valve leaking, after burning, late injection, egb fire, fuel pump
timing incorrect.
130. 2 hour notice, action for sailing. Aux gen, lo/ fo/ purifier, propeller clearance, prelube, turning, stering
gear test, control test, t/c drains and main air start line drains shut, top up air bottle, blowers on auto, blow
through,
131. M/E parameters and safety devices.
132. Black smoke coming out of exhaust, reason and action. Improper combustion, dripping injector, fuel
bad quality, scavenge ports chocked,
133. Expansion tank getting overflow. What actions if you are the watchkeeping engineer. Drain water,
134. Setting of fuel pump timing, reason for change in timing.
135. Regulation for crankcase relief v/v
136. Checking of tappet clearance after decarb of engine.
137. Quantity of air required for starting of A/E. 7k air motor
138. While 0/H of engine, before completing the 0/H job, 2/E was going on leave. Work is in incomplete
position. I-low to attend the job to complete the same 0/H.
139. Lub and cooling system of MIE.
140. Timing diagram.
141. How to lower and raise the plunger of fuel pump
142. Piston diagram of 2/S, 4/S.
143. Fuel value, fuel pump.
144. Function of piston rings, scrapper ring.
145. Piston cooling.
146. Removing of liner as a full E/R incharge.
147. Low L.0. Pressure cut-out according to last ship. 1.8
148. Indications of scavenge fire.
149. What is surging and why? Imbalance between air delivery by t/c and air take off from manifold.
150. Indication diagram.
151. Crankshaft deflection.
151.Why T/C is fitted, can we run without T/C?
152 .Types of scavenging.
153.Take over watch.
154.Funnel spark.
155. How to avoid sparking? Proper fuel preparation and injection, timing, good quality fuel, egb soot
blow,
156.Engine starting flow diagram.
157. Safeties of M/E.
158.What is power? Rate of doing work.
159.Crank pin dia measurement. Crank pin top bottom, port starboard.
160.Vemier calliper (zero setting)
161.Fuel injector testing.
162.Piston ring calibration. Axial clearance, butt clearance, radial clearance.
163.Air starting line, safeties. Bursting disc, relief valve, stop valves on air bottle, main air stop valve nrv,
drain valve at lowest point, separate filling and main air line on bottle.
164.Liner gauging. Template in fwd-aft and port starboard direction. Various point from top to bottom.
165. Propeller + rudder drop and effect. Propeller drop- whirling of propeller, increase in load on stern tube
bearing, loss of lubrication, cracks in tail shaft, vibrations, loss of propelling efficiency, chance of water
leakage into e/r. rudder drop- wear of rudder carrier bearing or pintle bearings. Slamming of rudder in
heavy seas, decrease in steerin efficiency.
166.Explain Air system of M/E. 30 k line-air bottle – main air valve- automatic block valve – distributor –
starting air valve.
167. Indication for air starting v/v leaking.
168. Flash point, power point, Auto ignition. Flash point is the minimum temperature at which the vapours
emitted by a volatile fluid are enough to give a momentary flash of fire and fire point is the temp at which
vapours are enough to support continuous burning. Auto ignition temp is the minimum temperature at
which the substance will ignite spontaneously without any external source of ignition.
169.Liner is coming with piston (during removal).
170.Exhaust valve opening. Overhaul – close spring air. Shut hp lo line. Close jcw water inlet and drain.
Remove hp line. Remove spring air line. loosen bolts hydraulically. Put I bolt on top, lift by crane. How
valve opens- opened by oil supplied from cam shaft lo system. Hydraulic pump on cam shaft. Hp oil
delivered to a cylinder on top of valve spindle. Inside cylinder is a piston which is actuated by hp oil which
opens the valve. Within the casing is another cylinder and piston. Space under this piston is supplied with
compressed air 6k. this causes exhaust valve to close when hp discharge stops.
171.A/E piston removal and checks. Piston rings, ring grooves, template for piston top profile, cracks,
gudgeon pin clearance and ovality,
172.Adjustment of compression ratio in trunk piston and 2 stroke. For two stroke use shims between palm
of piston rod and cross head pin. Trunk piston engines-
173.Bearing and clearance.
174.MCR, How to calculate? Maximam continuous rating, it is said to have reached when one or more of
these factors are fulfilled- maximum quantity of fuel burnt efficiently in the engine, maximum safe stresses
on the engine parts without failure, when the mean piston speed and revolution can not be increased safely
any more.
175.M/E trip, How to check?
176.Difference between 2S, 4S connecting rods. 2s- flat palm bearing top and bottom, 4-s- oblique type con
rod with bush @ top end.
177.Chain elongation. Due to slackness the cam shaft may lag behind crank shaft which delays all timings.
Provided that total stretch is within maximum limits, chain can be tightened to reduce slackness. Chains
generally do not elongate but slackness is due to wear down of sprockets. Slack adjusted by chain
tensioning device which functions by moving a sprocket in and out to take up slack. As the chain is
retensioned the cam shaft sprocket eventually gets retarded thus causing change in timings.
I 78.Steering safeties. Relief shock valves, buffer relief valves, by pass valves, isolating valves,
replenishing pump, standby pump, motor overload alarm, hyd oil lp alarm, tank low level alarm, supply
from esb, control system failure alarm, steering failure alarm, power failure alarm.
179.Engine not reversing, what to check? Reversing servomotor at end position, relief valve on pneumatic
cylinder for camshaft shiting, lifted, running direction interlock, cam position interlock, air bottle pressure
low
180.AlE not starting, What are checks? Lo priming pump not running, turning bar not in place, fuel pump
rack stuck, distributor not working properly, piston seized In liner,
181.How to remove piston?
182.Starting and reversing.
183.Mean piston speed. Average speed of piston in reciprocating engine. Function of stroke and rpm. It is
a indicator of class and performance of the engine. Given by {2*stroke length*rpm/1000*60 } in m/s.
increases from zero @ beginning of stroke to maximam near mid stroke and zero at ends. If connecting rot
is of infinite length then mps and acceleration would be in simple harmonic motion.
184.Power from indicator card
185.Funnel black smoke, reasons.
1 86.Cetane numbers. Cetane number of distillate fuels is an indication of combustion quality of the fuel. It
is the percent volume of n hexadecane (cetane ) in a mixture of n-hexadecane and alpha methyl naphthalene
which gives the same ignition delay as the sample fuel in a test engine. CCAI(calculated carbon aromaticity
index) is used for distillate fuels
187.How you know starting air v/v is leaking?
188.Lub of cylinder liner. Pump driven by M/E draws oil from main bearing system and supplies via speed
control valve to a hydraulic motor which runs cyl lub oil pump and exh vv lo pump. Cyl oil to pump by
gravity, each pump having a cam operated plungers driven by hyd motor. Plungers supply oil to cyl quills
via accumulator.
1 89.Exhaust v/v. inlet v/v clearance. 0.5 mm exh vv, 0.2-0.3 inlet vv
190.Thrust bearing, clearance, maintenance, functions.
191.Piston material. 2s- crown- casting of low alloy steel with nickel, chromium and nickel. Piston skirt- ci.
4s- allumunium alloys. Ring grooves chromium plated, piston rod- forged steel.
192.Liner material. Spheroidal grey cast iron
193.Sump lub oil level decreases. Purifier overflow, heater leakage, cooler leakage,
194.Diesel knock (TDC knock. BDC knock) diesel knock @ tdc due to ignition delay. Bdc knockmechanical
knock hammering between moving parts or moving and stationary parts.
195.Single throw crank. Single throw means a set of web+pin+web between two journals. Double throw
web+pin+flying web+pin+web between two journals
196.Types of exhaust v/v
197. A/E 500 hour, routine maintenance. injectors
198.Fuel injector cooling types. Diesel oil / Water cooled
199.Difference in lubrication of sulzer and B&W? crosshead lube oil pump.
200. M/E main and cross head bearing lubrication.
201.Cross head lubrication in B&W.
202.Camshaft drive. Chain drive or gear train.
203.Need for 2 exhaust valve on A/E. increase in area, reduction in weight of valve and spring, reducing
inertia force and valve bounce, increase in volumetric eff
204.Manoeuvring diagram, safety, air-governor, emergency stop, ahead, astern, pilot signal to air
distribution, air distribution interlock, other interlock circuit, crash maneuvering, emergency.
205.Camshaft lubricating oil pump. Tank-filter-pump-cam shaft casing- drain- magnetic filter-tank. Drains
so placed to retain some oil and cam to dip.
206. Why water in air bottle? Condensation on cooler part of the bottle
207.Difference between flywheel and governor. Flywheel retains energy for use during comp stroke in 2s
and suc/comp/exh stroke in 4s. governor maintain speed of engine by varying fuel supply.
208.Exhaust v/v burn out indication. Increased exh temperature, high jcw outlet temp
209.Scrapper ring functions? Why holes are provided? Oil flowing down the liner is carried up again by the
ring, to drain the scrapped oil back into the cc.
210.Generator not starting on air, decks?
211 .Generator arrangement.
212. Power balancing approx equal power developed in each unit. Carried out by varying amount of fuel to
each unit.
213.OMD calibration. Check button provided, meter should move to max, red indicator warning lamp and
remote lamp to light and audible alarm should sound.
214.Engine not starting on air and fuel.
215.Scavenge fire inspection
216.Boiler air fuel ratio.
217.Indicator card reference line.
218. Sulzer reversing mechanism.
219. How T/G effects starting of engine, what if cut off?
220. While entering a channel, engine J. W. cooling temperature is raising, what action wi11 you take? Use
high sea suction, c/o cooler or put both coolers in use
221.Charging piston rings (procedure)
222.Exhaust temp is going high, actions taken.
223.Setting of overfeed trip and its working. 115% for gen and 120% for me comes to action when
governor fails. Shuts fuel supply. Overspeed trip required for safety reasons.
224.Cylinder head v/v opens inward (reason) if opening upwards cyl hd needed of split construction.
Spring exposed to exh gases, deterioration. Closing force required would be more, spring size increased.
225.Gear inspection? What is backlash? 1-low much it should be? Normal cond- .24 to .41, max-.73mm,
clearance between two enmeshing gears, measured by means of feeler or micrometer with enmeshing gears
in line with center.
226. Max. allowable wear of cylinder liner. 0.6 to 0.8 of original dia.
227.What is mech efficiency? Why is it less in 4 stroke?
228.How to check o/s trip?
229.Piston running hot indications and action to be taken?
230. Firing order of last ship? 162534
231.Sequence of admitting starting air in cylinder.
232.Air distributor.
233.A/E decarb, safety precautions.
234.Liner removing instructions.
235.Line calibration, clearances
236.HP/KW 1hp = 746 w = 0.746 kw
237.Crankshaft deflections, out come, why is it taken, what happens if not correct.
238.Bridge gauge used where, how clearance measure.
239.Timing of 4-s.
240.Test carried out on L.O. water content, alkalinity, drop test, viscosity,
241.How will you check the fuel pump liming’?
242.Causes of less L.O. Pressure. Filter chocked, pump efficiency reduced, blockage of oil holes and pipes,
contamination of lo.
243.How mechanical seal works. Carbon or ceramic seal face
244.Prove uniform scavenging is better than other types.
245.How cylinder lub in 4-s and 2-s is actived.
246.Draw crank position diagram for cylinder lubrication. P 177 dk sanyal
247.What is overlap? (Advantage and Disadvantage) efficient scavenging and loss of scavenge air.
248.How does the air enter into the cylinder?
249.Cylinder head tests. Pressure test, crack test.
250.How do you remove cylinder head?
251.Fuel injector, checks. Opening pressure, spray, interference fit between needle valve and bore, hole dia,
lapping of nozzle face, needle valve lapping
252.Fuel pump function.
253.How do you know come to know starting and ending of injection of fuel?
254.Safeties provided in starting air system.
255.How reversing of M/E takes place?
256.What is long stroke engine? Advantages? Regulation.
257.Bearing clearance. 0.3 to 0.4
258.Crankshaft misalignment.
259. Manoeuvring line diagram.