1. Procedure for Overhaul of A/E.a. Check whether all tools and
spares are available or not.b. If so, then start the Stand by
generator.c. Check all parameters are normal.d. Now share the load
with the help of synchroscope.e. Again check all the parameters are
within normal range.f. Put full load on the Stand by generator.g.
Stop the generator on which work has to be carried out.h. Put MEN
AT WORK tag.i. Shut the air starting valve, fuel oil inlet &
outlet valves and isolate the system.j. Let lube oil priming pump
run for half hour after then stop it.k. Drain the jacket water.l.
Remove the cylinder head cover.m. Remove high pressure pipe.n. Take
out the injector using its tool.o. Open the rocker arm bolts &
remove it from its place.p. Remove the Jacket water outlet pipe.q.
Disconnect the scavenge & exhaust manifold from the cylinder
head.r. Open the cylinder head bolts using the Torque spanner or
hydraulic jack(As provided on your vessel).s. Check the lifting
gear (Crane & chain block, Eye bolt, etc.)t. Lift the cylinder
head & put it at a suitable place. mount cylinder liner
retaining tool consisting of two tubes on two studs atcylinder head
before piston removal.screw on the nuts and tighten them
slightly.u. Open the crankcase door.v. Bring the piston to TDC
position & attach eye-bolt on it and Attach hook of chain block
to it.(Before bringing Piston to TDC, the top part of liner needs
to be cleaned)w. Bring the piston to BDC and open the bottom-end
bolts & remove bottom end bearing.x. As load of piston is now
on Lifting gear, so take it out & put it on the piston stand.y.
Remove the piston rings using ring extractor.z. Remove the circlip
from the gudgeon pin & take out the gudgeon pin, so connecting
rod can be taken out.1. How do you decide if piston rings should be
changed or not?a. Butt clearance increased then its normal range.b.
Axial clearance increased.c. Visual condition of piston ring.1. How
you check lifting gear.a. Check the condition of wire rope &
grease it.b. Check the visual condition of chain.c. Check the limit
switches in the forward, aft, Port & starboard direction are
working.d. Check that emergency button is working.e. Check the
visual condition of the insulated cover is satisfactory.f. Check
overload trip is working satisfactorily.g. Check the visual
condition of chain block, no cracks should be there.h. Check that
safety latch is there on chain block.1. What checks on piston and
liner.a. Piston:-i. Check the piston for any cracks.ii. Check the
piston top profile.iii. Check for any carbon deposits.iv. Check the
butt clearance, axial & radial clearance.1. What to do if valve
seat damaged?1. Checks on crankcase inspection in Main
Engine?Safety Precautions:1. Inform bridge and Chief Engineer.2. If
in port, take Immobilization certificate.3. Get propeller clearance
from the duty officer.4. Shut off starting air valve.5. Put Men at
Work tag.6. Stop lube oil pump.7. Indicator cocks to open.8.
Turning gear should be engaged9. Wear proper PPE, Shoes &
helmet.10. No naked lamp to be taken inside.11. Open the crankcase
door taking it as a shield.12. Ventilate the crankcase door
properly.13. No items should be inside the pockets of boiler
suit.Inspection:a. Check the condition of lube oil, for any smell,
discoloration, degradation.b. No paint parts to be there in the
sump.c. Turn the engine to BDC and under stuffing box area for any
black oil.d. Check piston rod for any scoring & roughness.e.
Check piston palm bolts & locking.f. Check the guide shoes and
the area around it.g. Check guide shoe end cover bolts.h. Check
X-head bearing general condition.i. Check all bearing for white
metal.j. Check oil pan area of every unit for any sludge
formations, bearing metals & foreign particles.k. Check top
& bottom of connecting rod bolts, nuts & locking device.l.
Check the axial movement of bottom end bearing.m. Check slippage of
web & journal by reference marks.n. Check the teeth of
transmission gear.o. Check the tightness of chain drive.p. Check
c/case relief door spring tension, wire mesh & sealing ring.q.
Check & clear the O.M.D sampling pipes.r. Start the lube oil
pump & check flow .s. Check c/case door sealing condition &
close it c/case door.t. Make sure no foreign matter or tools should
be left inside the c/case.1. Tappet clearances why plus how to
check.Tappet clearance is taken to ensure positive closing of the
valve & for thermal expansion of the valve.Taking all safety
precautions.(See Ans. 1)Make sure the piston is on TDC.i. From the
marking on the flywheel.ii. From the fuel cam.iii. Push rod should
be free.Make sure the engine has cooled down.Loosen the lock nut of
the rocker arm.Now adjust the tappet clearance between the rocker
arm & valve stem by tightening or loosing the nut below the
lock nut.If tappet clearance is less:i. Valve will open early &
close lateii. Air induced through inlet valve may leak out. So,
less air for combustion.iii. Power will be reduced.iv. Fuel
consumption will increase, engine may become unbalanced, exhaust
temp. will be very high.v. In worst condition, valve may remain
open, resulting in loss of compression pressure, burning of exhaust
valve, T/C fouling will increase.If tappet clearance is more:i.
Valve will open late & close early.ii. Lesser heat energy to
T/C, so reduction in scavenge air & hence power.iii. No proper
removal of gases.iv. Hammering of valve stem-may cause damage to
valve stem.1. What to check if Engine is not starting on air and
fuelEngine not starting on Air:-a. Low air bottle pressure or air
line valve may be shut.b. Air bottle isolating valve or automatic
valve or distributor not functioning.c. Control air valves faulty
or less control air pressure.d. Start air automatic valve jammed.e.
Turning gear engaged.f. Reversing has not taken place completely.g.
Control valve for fuel or start is not in its end position.h.
Bursting diaphragm on start air line damaged.i. Fuel lever on
maneuvering stand not on remote mode.j. Auxiliary blower not
running or not on auto mode.k. Emergency stop has activated.l.
Interlock is operated.m. Cylinder air start valve defective or
sticky.n. Piston not in firing mode.Engine not starting on fuel:a.
Less fuel in service tank.b. Fuel filter is chocked.c. Fuel supply
pumps not delivering required pressure. Or fuel pump tripped.d.
Fuel level on local maneuvering stand, is not on remote stand.e.
Fuel rack stuck.f. Fuel pump malfunctioning, jammed plunger.g.
Injector nozzle needle sticking or holes blocked.h. Compression
pressure is too low due to broken piston ring or exhaust valve not
closing properly.i. Fuel pump relief valve leaking.j. Start air
pressure insufficient to turn the engine fast enough.1. What to
check if Engine is not taking load.1. What precautions to take to
start A/E After overhaul.a. Water tightness to be checked.b. Air to
be removed from jacket water outlet line.c. Priming lube oil pump
to run before starting the engine.d. Check the lube oil level.e.
Check the flow of lube oil.f. Blow through the engine before
starting.1. How to change purifier to clarifier.Remove the gravity
disc.1. How to select damn ring for purifier.From the monogram
provided with manual, which is drawn with respect to viscosity of
oil & which size damn ring to be used.If monogram not there,
thena. Chief Engineers experience will come into use.b. Hit &
trial method to be used.i. First use the largest gravity disc and
whether oil is overflowing, if so, then use small size gravity disc
and follow this process until oil stops overflowing.1. What to
check if purifier over flowing.a. Size of gravity disc.b. High
throughput.c. Temperature of the oil.1. How to stop Aux Engine if
not stopping by stop handle.a. Pull the fuel rack to zero
position.b. Operate any trip.1. Charging gas in Dom Fridge?1. Close
the receiver outlet valve and collect the gas in the receiver.2.
Check the liquid level, if it is below L/3, Charging is reqd.3.
Check the weight of the refrigerant bottle & keep it upright.4.
Connect the charging line to the connecting point and keep it
loose.5. Open the bottle valve slightly and purge the line into the
collecting cylinder and then tighten the connection.6. Open the
charging valve and fully open the bottle valve.7. Check the liquid
level in the sight glass and make sure no air bubble present in the
system.8. Close the charging valve and the bottle valve.9. Open the
receiver outlet valve & start the compressor.10. Carry out let
detector test.1. Charging oil in Domestic fridge.Method 1.1. Mostly
ships have hand p/p provided which develop more pressure than the
inside pressure.Method 2.1. Reduce the L.P Cut out setting.2. Dip
the pipe inside the c/case of compressor.3. Run compressor, vaccum
will develop.4. So, compressor will start sucking the oil.5. Make
sure the pipe is diped fully, because it has got chances of sucking
air.6. If air gets in, then purge it in a separate bottle after
charging of oil gets completed.1. What to check if Room temp (one
room) not coming down?-1. What to check if all room temp not coming
down?- Room doors not shut properly.- Room insulation is bad.- Air
in system.- Room fans not running.- Evaporators frosted.-
Compressor not working satisfactorily, unloader defective, valve
leaky, rings damagd.- Expansion valves choked/ malfunctioning.-
Evaporator blocked.1. What to do if dom. fridge is short cycling/-
L.P Cut out is defective.- L.P Cut out setting not correct, too low
difficult for Cut In.- Lesser gas flow1. Less gas in system.2.
Drier Choked.3. Expansion valve filter choked or Expansion valve
Malfunction.4. Evaporator Choked.5. Compressor valves
leaking.Actions:-a. Check L.P. Cut out setting, Cut out pressure
OK.b. Check flow of gas by seeing sight glass which should show
full flow of refrigerant.c. If no full flow- Either less gas or
drier chocked, Clean the drier.d. Check level in receiver, if low,
then charge gas.e. Expansion valve filter choked, then clean it.f.
Expansion valve malfunctioning- Change it.g. Evaporator choked-
Blow-thru evaporator with nitrogen.1. Overhaul of centrifugal
pump.1. Changing pipe join below floor plate without removing
pipe.1. Can not pump out bilges. What checks? What to do if pipe
holed?1. Check Sounding of bilge tank.2. Check Bilge tank outlet
v/v open or not.3. Check P/p inlet v/v open or not.4. Check p/p
working properly.5. If vaccum developing that means hole in
pipeline.If pipe is holed:-1. Carry out Vaccum test by closing
inlet valve & opening outlet /v.2. If hole is between the inlet
v/v and p/p, vaccum will develop, now remove top of v/v and put
water.3. If hole is in between Inlet v/v and bilge tank outlet v/v,
then again put S.W1. Boiler press coming up and gone above the
safety valve lifting pressure. What to do?Use the easing gear to
release the excess pressure.1. Bridge informs steering not
responding. What to do?1. Air comp bumping clearance how to check
and adjust.1. Start the Stand by compressor.2. Stop the compressor
whose bumping clearance has to be taken.3. Isolate the system.4.
Put Men at Work tag.5. Loosen the cylinder head bolts and lift
it.6. Measure the diameter /size of the lead ball.7. Bring piston
to TDC and put lead ball on centre of it.8. Now, put the cylinder
head and tighten it to required torque.9. Now, again loosen the
cylinder head bolt and remove the ball.10. Measure the size of the
ball.11. The difference between the initial size and final size is
the bumping clearance.It can be adjusted by either putting a
thinner gasket or putting shim on top half of the bottom end
bearing.1. Removal of broken stud.First drill the stud little bit
& then use Thread extractor which has left hand thread.1.
Bridge informs lot of smoke from funnel what to do?1. Reduce load
on engine.2. Check purifier operating alright/ reduce throughput to
have better purification.3. Drain water from settling & service
tank.4. Check scavenge air temperature & adjust if reqd. .5.
Soot blow the economizer.6. Ensure, fuel oil end heater outlet
temperature proper corresponding to attain viscosity at the point
of injection.7. Check, if any particular Exhaust temperature is
higher than others, if so, then stop the engine, Change the
injector with a spare overhauled injector.8. Check all fuel pump
timings are correct or not.9. Dismantle and carry out overhaul of
T/C.10. Send fuel oil for Laboratory analysis.Reasons:1. Improper
combustion.2. Burning of carbon particles collected at EGE.3.
Overloading of engine.1. Flooding in Engine Room what to
do?1.Inform bridge & Chief engineer.2.Raise engineers
call/emergency alarm.3.Before starting bilge pump note down the
position of vessel & time of starting.4.Other engineers will in
between try to locate the hole or burst of pipe and repair.5.If
ingress of water very high, start another pump.6.Reduce the engine
r.p.m.7.Change over main s.w suction to emergency bilge
suction.8.If level is still coming up try to protect the motor from
short-circuiting , if required start emergency bilge suction
valve.9.If situation is not coming in control, prepare lifeboat for
lowering.1. What checks to be made on Aux Engine when
running?Checks:1. Check scavenge air temperature.2. Check Exhaust
gas temperature.3. Check r.p.m4. Check load on A/E.5. Carry out
peak pressure.6. Check for any abnormal noise or vibration.7. Check
jacket water inlet & outlet temperature.8. Check Lube oil
temperature & pressure.1. During running Main Engine stops.
What checks?1. Check whether Emergency stop operated by any
personnel.2. Check level of fuel oil in Service Tank.3. Check
whether purifier working properly.4. Check whether water is there
in Service tank due to improper purification.5. Low lube oil
pressure trip operated, Check L.O P/p developing correct
pressure.6. Control air trip operated, Check control air
pressure.1. Boiler blow back what to do and reasons?Reasons:-1.
Insufficient pre-purging.2. Blower not working.3. Accumulation of
oil.4. Leaky solenoid valve.5. Dripping of burner.Action:-1. Stop
the firing.2. Check the condition of burner, if it is dripping,
then overhaul is required.3. Do the inspection of the furnace.4.
Carry out sufficient pre-purging.5. Start the boiler on Auto
mode.1. Boiler extinguishes what to do?1. Accept the alarm.2. Find
out the reason for extinguishing:-3. if too low water level alarm
came, then check pump is developing correct pressure or not , its
is working properly.4. If Tripped on high pressure, let the steam
pressure come down.5. Fuel oil low pressure alarm , then check
functioning of fuel pump, oil in service tank.6. Fuel oil low temp.
alarm, then use the heater.7. Flame failure trip, then clean flame
eye, check the furnace & overhaul the burner.1. Overhaul of
fuel valve?Safety Precautions:-a. Check whether all tools and
spares are available or not.b. If so, then start the Stand by
generator.c. Check all parameters are normal.d. Now share the load
with the help of synchroscope.e. Again check all the parameters are
within normal range.f. Put full load on the Stand by generator.g.
Stop the generator on which work has to be carried out.h. Put MEN
AT WORK tag.i. Shut the air starting valve, fuel oil inlet &
outlet valves and isolate the system.j. Let lube oil priming pump
run for half hour after then stop it.k. Remove the lock nut of the
high pressure pipe.l. Now, remove the high pressure pipe.m. Take
out the fuel injector using it tool.n. Put it on the testing kit.o.
Check the lifting pressure, atomization, pressure falling steadily,
dripping of oil.p. Now, take out the injector from the testing kit,
put in a diesel oil & clean it.q. Make sure the workshop table
should be clean, no rags or jute to be there.r. Put the injector on
the vice and tighten it.s. Loosen the lock nut of the injector.t.
Now loosen the compression nut to release the spring pressure, then
take out the spring.u. Open the cap nut and take out the needle and
guide.v. Put the parts on the cleaned table.w. Check the condition
of spring by dropping on the floor plate, it should jump and also
check it by tightening in the vice and then releasing. The
difference in the length,no cracks to be there.x. Check visually
needle, there shouldnt be any scoring marks because it is made of
Nitrite material.y. Try to insert the needle inside the guide at
angle of 45degree, the needle should on its own weight.z. Check the
size of injecting holes by using Go or No go gauge.i. If go gauge
is going then hole size is OK.ii. If no go gauge going, then it
means the size has increased, then nozzle needs to be changed.iii.
Now assemble the injector and do the lifting pressure setting on
test kit by adjusting the compression nut.iv. After this check the
injector again for its lifting pressure, atomization, steady fall
of pressure and dripping.1. How pressure testing of Globe Valve is
done?a. Blank one side of valve and put water from the other side,
check for any leakage.1. Overhaul of a cylinder head & what all
to check?1. Overhaul of Inlet & exhaust valve of aux.enine?1.
Function of Roto-Cap in valves & how it is overhauled?a. It
helps to rotate the valve during operation with the help of the
exhaust gas, so as less wear occurs and stress doesnt comes only at
one point.1. What is dye-pentration test, why is it done & how
is it done?Dye-Penetration test is a leak test carried out to know
about the leakage/ crack in any part.In it, first the part or unit
is cleaned, paint is removed where the crack is suspected, then it
marked on the unit. If water is coming, then colour will change,
which shows the crack.1. How alkalinity test is carried out?1. Take
200 ml water sample in the stoppered bottle.2. Add one P.Alkalinity
tablet & shake or crush to disintegrate.3. If P.Alkalinity is
present the sample will turn blue.4. Repeat the tablet addition,
one at a time, until the blue colour turns to permanent yellow.5.
Count the number of tablets used and carry out the
calculation:P.Alkalinity, ppm CaCO3 = (Number of tablet x 20) -10f.
Record the result obtainied on the log sheet provided, against the
date on which result was obtained.1. Why water is kept heated in
hot-well?1. To prevent oxidation2. To avoid thermal stress on
boiler.1. Position of Unloader in AC & Ref. compressor
?Unloader in AC & Ref. compressor is located near the suction
valve of the compressor.1. What all clearances taken in centrifugal
pump?1. The wear ring & impeller.2. The wear ring & the
casing.3. Shaft and the bush.1. Why centrifugal pump is not self
priming?Because of the churning effect it is not be able to remove
air positively as mass of air is relatively zero.1. What is the
position of bearing in centrifugal pump?Near the impeller.1. What
is the position of piston when taking bearing clearances- Main
Bearing Clearance --B.D.C- Bottom End bearing clearanceB.D.C-
Cross-head bearing clearance.B.D.C1. How to overhaul gear pump and
centrifugal pump? And clearance to take.1. How to take out
connecting road?1. How to test cylinder head relief valve
onboard?1. During maneuvering Bursting disc of air compressor get
damaged, what action to take?1. Inform the bridge about the problem
and to give lesser kicks.2. Start the stand by compressor.3.
Isolate the compressor whose bursting disc is damaged.4. Change the
bursting disc, if available onboard.5. If Not available, then let
the S.W go into the E/room bilges, otherwise Fresh water cooled ,
then join a flexible hose and put into the expansion tank.1. How
will you test the crankcase relief door?The testing of the C/case
relief door is done at shore.1. Reasons of Purifier overflow?2.
Procedure for doing boiler blow down?Precautions1. Ensure nobody is
near the ship side blow down valve.2. Not to be carried out in
drydock or alongside.3. Valve sequence to be followed.4. Boiler
shouldnt be left unattended during blow down.5. Monitor the end of
blow down. Long blow down to be avoided.6. Dont blow down to the
E/room bilges.Procedure1. Ship side valve 1 is opened followed by
valve 2.2. Valve 2 is NR which is fully opened to avoid cutting off
seat.3. Rate of blow down controlled by Valve 3.4. For scum blow
down valve 4 & 5 are used.1. Action to be taken, if chloride
content is excess?Blow down of boiler to be carried out.1. How to
blow through boiler Gauge Glass?Procedure:1. Make sure drain line
is clear2. Close the steam outlet valve.3. Close the water outlet
valve.4. Open the drain valve.5. Open the water out valve & let
water flow thru it and close the valve after blowing down with
water.6. Open the steam out valve and blow thru with steam.7. Close
steam valve.8. Close the drain valve.9. Now, open the water side
valve.10. Let water fill up 3/4th gauge glass.11. Open the steam
valve slowly.1. How to tighten boiler gauge glass after
overhauling?Procedure of tightening:1. First tighten all the bolts
by hand slightly without putting any pressure.2. Now, tighten bolt
1 & 2 equally. Then 3 & 4.3. Tighten bolt 5 & 6. then 7
& 8 equally.4. Tighten bolt 9 & 10.5. Now again tighten 7
& 8. Then 5 & 6.6. Tighten bolt 3 & 4. then 1 &
2.Or you can say we first tighten outward bolts of both side &
then inward side.Then we move in opposite steps. i.e. tight inward
bolts & then outward bolts.Differences betwn Watercooled and
Oilcooled piston
W - High specific heat capacity therefore removes more heat per
unit volumeO - Low specific heat capacityW - Requires chemical
conditioning treatment to prevent scalingO - Does not require
chemical treatment but requires increased separate and purification
plantW - Larger capacity cooling water pump or separate piston
cooling pump and coolers although less so than with oilO - Larger
capacity Lube oil pump, sump quantity and coolersW - Special piping
required to get coolant to and from piston without leakO - No
special means required and leakage not a problem with less risk of
hammering and bubble impingement.W - Coolant drains tank required
to collect water if engine has to be drained.O - Increased capacity
sump tank requiredW - Pistons often of more complicated designO -
Thermal stresses in piston generally less in oil cooled pistonsW -
Cooling pumps may be stopped more quickly after engine stoppedO -
Large volumes of oil required to keep oxidation down and extended
cooling period required after engine stopped to prevent coking of
oil