Major project report vi sem

GOVT. POLYTECHNIC KANGRA | H.P.
1
PROJECT REPORT ON
MAINTENANCE OF DIESEL AND PETROL ENGINE
SUBMITTED IN THE PARTIAL FULFILLMENT OF THE REQUIREMENT
FOR THE AWARD OF DIPLOMA
IN
MECHANICAL ENGINEERING
FROM
GOVERNMENT POLYTECHNIC KANGRA
UNDER THE SUPERVISION OF
ER. D.R. SHARMA
(H.O.D MECHANICAL ENGINEERING)
SUBMITTED BY
S.No. Name S. No. Name
1. Pankaj 7. Rohit
2. Punnet 8. Sajan Lakhanpal
3. Rajat Dhiman 9. Santosh
4. Rajnesh Kumar 10. Shantanu Rana
5. Reshav 11. Shubham Awasthi
6. Robin Bhardwaj 12. Shubham Chaudhary

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GOVT. POLYTECHNIC KANGRA
(AS ISO 9001 : 2008 CERTIFIED INSTITUTE)
DEPARTMENT OF MECHANICAL ENGINEERING
CERTIFICATE
Certified that the project entitled “MAINTENANCE OF DIESEL AND PETROL ENGINE”
submitted by Pankaj Dheer, Punnet, Rajat Dhiman, Rajneesh Kumar, Reshav, Robin Bhardwaj,
Rohit, Sajan Lakhanpal, Santosh Kumar, Shantanu Rana, Shubham Awasthi, Shubham
Chaudhary in the partial fulfilment of the requirement for the award of DIPLOMA in
MECHANICAL ENGINEERING of HIMACHAL PRADESH TAKNIKI SHIKSHA BOARD DARI,
DHARAMSHALA is record of student’s practice work carried out under our supervision and
guidance. It is further understood that by this certificate the undersigned do not endorse or
approve any statement made, opinion expressed or conclusion drawn there in but approve
the report only for the purpose for which it is submitted.
Supervisor Head of Department
Er. D.R. Sharma Er. D.R. Sharma
Er. Parul Dhiman

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ACKNOWLEDGEMENT
No volumes of words are enough to express our gratitude toward our guides Er.
PARUL DHIMAN, LECTURER in Department of Mechanical Engineering,
Government Polytechnic Kangra who have been very concerned and have
guided for all the ideas and solved our quires in the preparation of this project.
They have been very co – operative and sincere to guide us through to see our
hard works become fruitful.
We are thankful to ER. D.R. SHARMA, Head of Department,
Mechanical Engineering, Government Polytechnic, Kangra and also our project
coordinator, for giving us the opportunity to carry out this project.
Most importantly we would like to thank almighty for showing use
the right path, to help us stay calm in the oddest of the time and keep moving
even the times when there was no hope.
Lastly we thank our friends and persons who were involved directly
or indirectly and spared time to cite valuable suggestions without which this
work would not have casted in to present form.

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TABLE OF CONTENTS
S.NO. DESCRIPTION PAGE NO.
1. Certificate 2
2. Acknowledge 3
3. Introduction (Diesel Engine) 5
4. Objective And Aim 7
5. Specification of Diesel Engine 8
6. Various Parts of Diesel Engine 9
7. Dismantling Procedure (Diesel Engine) 14
8. Common fault and solution of Diesel Engine 15
9. How to Diagnose Fuel Injector Problem 18
10. Maintenance of Petrol Engine 23
11. Technical Specification (Petrol Engine) 24
12. Tool and Equipment Used 25
13. Dismantling Procedure (Petrol Engine) 26
14. Main Parts (Petrol Engine) 27
15. Common Faults (Petrol Engine) 29
16. How to Diagnose Carburetor Problem 30
17. Symptoms of bad or failing spark plug 33
18. Symptoms of bad or failing distributor rotar and cap 36
19. Proper Firing order of a 4 Cylinder Petrol Engine 38
20. Cost Estimation 39
21. Conclusion 41
22. Reference 42

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INTRODUCTION (DIESEL ENGINE)
The diesel engine (also known as a compression-ignition or CI engine) is
an internal combustion engine in which ignition of the fuel that has been
injected into the combustion chamber is caused by the high temperature which
a gas achieves (i.e. the air) when greatly compressed (adiabatic compression).
Diesel engines work by compressing only the air. This increases the air
temperature inside the cylinder to such a high degree that it ignites atomized
diesel fuel that is injected into the combustion chamber. This contrasts with
spark-ignition engines such as a petrol engine (gasoline engine) or gas
engine (using a gaseous fuel as opposed to petrol), which use a spark plug to
ignite an air-fuel mixture. In diesel engines, glow plugs (combustion chamber
pre-warmers) may be used to aid starting in cold weather, or when the engine
uses a lower compression-ratio, or both. The original diesel engine operates on
the "constant pressure" cycle of gradual combustion and produces no audible
knock.
The diesel engine has the highest thermal efficiency (engine efficiency) of
any practical internal or external combustion engine due to its very
high expansion ratio and inherent lean burn which enables heat dissipation by
the excess air. A small efficiency loss is also avoided compared to two-stroke
non-direct-injection gasoline engines since unburned fuel is not present at valve
overlap and therefore no fuel goes directly from the intake/injection to the
exhaust. Low-speed diesel engines (as used in ships and other applications
where overall engine weight is relatively unimportant) can have a thermal
efficiency that exceeds 50%.

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Diesel engines may be designed as either two-stroke or four-stroke cycles.
They were originally used as a more efficient replacement for stationary steam
engines. Since the 1910s they have been used in submarines and ships. Use in
locomotives, trucks, heavy equipment and electricity generation plants followed
later. In the 1930s, they slowly began to be used in a few automobiles. Since the
1970s, the use of diesel engines in larger on-road and off-road vehicles in the US
increased. According to the British Society of Motor Manufacturing and Traders,
the EU average for diesel cars accounts for 50% of the total sold, including 70%
in France and 38% in the UK.
The world's largest Diesel engine put in service in 2006 is currently
a Wärtsilä-Sulzer RTA96-C Common Rail marine diesel, which produces a peak
power output of 84.42 MW (113,210 hp) at 102 rpm.

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OBJECTIVE AND AIM
OBJECTIVE:
To learn the proper technique of dismantling a single cylinder diesel engine to
study the function, material and serviceability of each part. Reassembly of
serviceable parts for proper function of the engine.
GENERAL AIM:
 develop logical processes of faultfinding
 learn the correct use and care of the tools and equipment associated with
this module
 be familiar with the function of the various components associated with
diesel engines
 develop safe working practices and be aware of the hazards of their
workplace or location
 perform a range of maintenance procedures associated with diesel
engines

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SPECIFICATIONS OF DIESEL ENGINE
Technical Specifications for high speed air cooled Single cylinder diesel Engine
(OMA -2)
Rating 4 – 8 KW/6.5 HP)
Governing Class – BI
Fuel H.S. DIESEL
Type OMA – 2
R.P.M 1500
SFC. 252g./kwh.
LUB. Oil SAE 30/40
Manufacture OPEX Engineering Corporation – Pahgwara

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VARIOUS PARTS OF DIESEL ENGINE (OMA -2)
 CYLINDER BLOCK: Cylinder block or Cylinder are main part of an engine. It
is a part in which combustion of fuel takes place. All other parts like piston,
connecting rod, crankshaft, water jacket etc. are bolted on it.
 PISTON: Piston is placed in the cylinder and transmits thrust to the
connecting rod. It is free to move. It compresses the air fuel mixture and
convert the fuel energy into mechanical energy. It transmits the power to
the crankshaft.
 CYLINDER HEAD: Cylinder head is fitted on the top of cylinder block and
the function of the cylinder head is to seal the working end of cylinder and
not to permit entry and exit of gases on cover head valves of the engine.
The valves, spark plug, camshaft etc. are fitted on it.

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 CONNECTING RODS: It connect piston to the crank shaft and transmit the
motion and thrust of piston to crank shaft. The lower end of connecting
rod is connected to the piston and the bigger is connected to the crank
shaft.
 CRANKSHAFT: It is located in the bottom end of cylinder block. It
transmits the reciprocating motion of piston into rotary motion. This
rotary motion used to rotate wheels of the vehicle.

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 CAM SHAFT: It is fitted either in the cylinder head or at the bottom of the
cylinder block. It is use to open or close valves at proper timing in multi-
cylinder engine.
 VALVES: It is fitted on the cylinder head. It regulates the flow of air fuel
mixture inside the cylinder and exhaust gas outside the cylinder block.

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When both inlet and exhaust valves are closed no pressure can go inside
or outside of cylinder block.
 INJECTOR: It is used in Diesel engine (Compression Ignition Engine). It is
fitted on the cylinder head. It is used to inject fuel in spray form inside the
cylinder at the end of compression stroke.
 PUSH ROD: It is used when the camshaft is situated in the bottom of the
cylinder head.
It regulates the timing of valves open and close through rocker arm and
camshaft.
 MANIFOLD: It is bolted on the cylinder head one each for intake and
exhaust. Its function is to evenly distribute air-fuel mixture for intake &
collects the exhaust gases from all cylinders.

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 PISTON RINGS: It provides the good sealing fit and less friction resistance
between piston and cylinder. It is split at one point so it can be easily
installed into the grooves cut in the piston.
 ENGINE BEARING: Bearings are used to support the moving parts. The
purpose of bearings is to reduce friction. The crankshaft is supported by
bearing. In engine two types of bearing are used sliding bearing and rolling
bearing.

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DISMANTLING PROCEDURE:
 Drain oil from the sump.
 Remove the rocker box and rocker assembly.
 Remove the push rods.
 Remove the air cleaner and silencer along with elbow pipes from the
cylinder head. Disconnect the high pressure line to the injector and take
out injector.
 Remove the inlet valve, exhaust valve, valve springs and valve cotters.
 Remove the side cover and loosen the big end of the connecting rod and
take out the piston along with connecting rod.
 Use ring expander to remove the oil and compression rings.
 Remove the circlips from the piston using circlip plier. Push out the
gudgeon pin and separate the connecting rod from the piston.
 Remove the cylinder block.
 Remove the timing cover and take out camshaft and crankshaft gears.
 Remove the fuel injection pump.
 Remove the side cover of the fuel injection pump.
 While removing the cam shaft, make sure that tappet rollers for inlet
valve, exhaust valve and fuel injection pump do not fall in the sump.
 Remove the fly wheel with puller.
 Remove the front and rear covers housing ball bearing for the journals.
 Remove the oil filter and plunger type oil pump and take out the crank
shaft from the crank case. Thus the engine parts are almost dismantled.
Clean all the parts for review to replace or service for assembly.

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Common Faults and Solutions of Diesel Engine
DIESEL ENGINE CANNOT START SEVERAL REASONS
Prerequisite for normal diesel engine operation is atomized diesel accurate and
timely sprayed into the combustion chamber and the combustion chamber of
compressed air to reach a sufficient temperature in order to fire outbreak. To
meet these two conditions, it must have a high enough speed and a certain
temperature within the cylinder diesel engine starting. Diesel engine cannot
start from the start of work, look for the causes of diesel engine fuel supply
system and compression.
 The ambient temperature is too low. In the case of low temperatures, the
engine warm-up should be prepared, otherwise difficult to start.
 Starting speed. Hand start diesel engine, you should gradually increase
the speed, and then pull the decompression lever to the non-
decompression position, so that normal compression cylinder. If the
decompression agency improperly adjusted or valve withstood piston,
tend to feel the shaking car is very laborious. Which is characterized by
the crankshaft to go to a site on the turn no more, but it can be returned
to. At this point, in addition to check the decompression institutions
should also check the timing gear meshing relationship wrong.
EXHAUST BLACK SMOKE FOR THE FOLLOWING REASONS:
 Uneven pressure fuel supply to the excessive or cylinder fuel supply
 Valve sealing leakage, resulting in leakage, low cylinder compression
pressure
 Air filter inlet obstruction, resistance of the inlet into the gas
 Cylinder, piston, piston rings severe wear
 Injector bad work
 Engine overload
 The fuel injection pump fuel delivery advance angle is too small, the
combustion process to the exhaust process
 Gasoline fuel injection system control failure
The black smoke of the engine through the high pressure oil pump
adjustment, fuel injector spray test to check the cylinder compression

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pressure measurement, inlet cleaning, fuel supply advance angle
adjustment, gasoline fuel injection system failure diagnostic work to be
inspected and excluded.
KNOCKING SOUND
Knock, refers to a piston working stroke of the moment, or piston row,
issued by the piston in the cylinder of the swing, the head and skirt and
cylinder wall collision "Dangdang" or "blah" abnormal sound. "Blah"
sound, the exhaust pipe to take the blue smoke, generally due to the
piston and cylinder wall clearance is too big reason. The main reason
for these are the following:
 If only after the cold start of this phenomenon. Running up to the
normal water temperature when away on its own, because the
piston and cylinder wall with the gap is too large, cold car piston
another contraction, both with the gap is further increased,
thereby percussion. Machine temperature rise after the piston
expansion, the gap tends to normal, it is abnormal sound
disappeared. This case no major problems in the short term.
 Oil grade and requirements does not match the engine flameout
a long time, started again, the oil viscosity, poor liquidity, the
short period of time the cylinder wall cannot form a good film,
piston and cylinder wall, directly resulting from collisions
knock. In operation for some time, the lubricating oil viscosity is
normal, the formation of a layer of film on the cylinder wall,
abnormal sound is diminished or disappeared. Reasonable
selection of lubricants, to warm up before starting the engine
crankcase, mixed with oil lubrication, before the start of multi-
step a few times to start the rod, so that mechanical adhesion
more lubricants, such a situation that is, can be avoided.
 Gas mixture in the cylinder cannot be normal combustion,
resulting in the moment of early burning or deflagration, or
engine no load fierce fuel door, will produce the sound of
crashing by the piston and cylinder wall. Should keep the engine
at normal temperature, to meet the octane requirements for
gasoline, and appropriate adjustments to ignition timing.

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 the piston skirt wear, cylindricity error is too large, the piston
line, the top will hit the cylinder walls, pistons and cylinder
serious wear and tear, the gap between the two?? Wall. The
biodegradable check, under the circumstances to take the
appropriate repair measures.
 due to rod bending and torsion, piston pin and the pin hole
deflection, crank pins and piston pin two axis lines not parallel,
will cause the piston in the cylinder skew run and hit the cylinder
wall. This situation can only decompose to check and replace the
corresponding parts in the diagnosis.

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HOW TO DIAGNOSE FUEL INJECTOR PROBLEMS
Fuel injection is the introduction of fuel in an internal combustion engine, most
commonly automotive engines, by the means of an injector.
All diesel engines use fuel injection by design. Petrol engines can use
gasoline direct injection, where the fuel is directly delivered into the combustion
chamber, or indirect injection where the fuel is mixed with air before the intake
stroke.
UNDERSTAND FUEL INJECTORS
Before setting to work diagnosing fuel injector problems, it helps to understand
what fuel injectors are. This section describes the basic process of how a fuel
injection system works and the role that fuel injectors play in this process.
FUEL INJECTION SYSTEM BASICS
A car's engine uses an internal combustion process to generate power, with the
two key ingredients to this process being oxygen and fuel. The engine takes
oxygen from the air surrounding it and fuel from the reservoir that holds the
car's gasoline. An air intake system delivers the air to the engine and a fuel
injection system delivers the gasoline. The engine's gas supply is limited, so in
order to use it efficiently the engine must apply the right amount of gasoline to
mix with the oxygen that it is receiving. Since the oxygen supply fluctuates, the
fuel injection system must constantly change the amount of gasoline that it

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delivers, and it must deliver the gasoline in a precise manner so as not to waste
any of it.
THE ROLE OF FUEL INJECTORS
Fuel injectors play a very important role in the engine's fuel delivery system in
that they deliver the exact amount of gasoline that the engine needs, even as
the requirements shift quickly and constantly. An injector is a valve with
electronic controls that receives signals from the engine control unit. A gas
pump delivers pressurized gasoline into the fuel injectors and the engine control
unit tells the fuel injectors to open a valve to let the pressurized gas pass through
an atomizing nozzle. The fuel injectors thereby spray a fine gasoline mist into
the engine's intake manifold, which then delivers it to the engine for combustion
with the oxygen that the engine is receiving. This mist makes for more efficient
burning of the gas in combustion than if it were in droplet form. The more
gasoline that the engine requests, the longer the valves in the fuel injectors stay
open. Pulse width describes the amount of time that the valves stay open.
BECOMING FAMILIAR WITH COMMON FUEL INJECTOR PROBLEMS AND THEIR
SYMPTOMS
This section describes the problems and symptoms that are related to fuel
injector problems. It is important for readers to be familiar with these problems
and symptoms if they plan to diagnose the fuel injectors on their own, as this
will help them to accurately diagnose problems.
COMMON PROBLEMS
This section lists the most common problems that are associated with fuel
injectors. Some problems are easy to correct, while others require
replacement of the fuel injectors.
Dirty Fuel Injectors
Fuel additives that do not spray into the intake manifold can leave a
residue on the fuel injectors. These can burn and form a crust because
fuel injectors run very hot due to the friction that is produced from rapid

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and repetitive movement. The crust on the fuel injectors can result in a
weak spray and an uneven pattern.
Clogged Fuel Injectors
Fuel injectors can also clog from the buildup of microscopic foreign
objects, which are usually in the form of rust. This is typically introduced
from a source upstream in the gasoline supply, such as the fuel supply line
or the fuel rail, and it can result from a car sitting idle without
maintenance for a long time. A clogged fuel injector will not be able to
supply gasoline to the intake manifold.
Fuel Injector Does Not Open
The valve in the fuel injector might not open as the result of faulty
windings or as the result of a rusted fuel injector. The windings might
overheat, short out, or break, and rust can cause the valve to stick. In any
of these instances, the valve will not open and the fuel injector will be
unable to deliver gasoline through its nozzle.
Fuel Injector Does Not Close
The valve in the fuel injector might also be unable to close due to a faulty
spring or due to a buildup of rust or fuel additives. If the valve is unable
to close properly, the fuel injector will leak gasoline.
Fuel Injector Leaks
The fuel injector may also leak gasoline if other parts of the system fail,
such as the mechanism that cools the injector. The fuel injector can then
overheat and fail, resulting in a leak. It is also possible that the injector
has a faulty part that does not enable it to function properly.
Symptoms That Can Signify a Problem
The table below describes the various symptoms that can signify a possible
problem with fuel injectors. It also associates the problems detailed above with
these symptoms.

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Symptom Description
Associated
Problems
Inconsistent Engine
Power
An inconsistent fuel supply can
cause the engine to rev high and
low, with the RPM gauge
fluctuating.
Dirty fuel injector
Misfiring Engine
When the fuel supply is
inadequate upon ignition, the
engine might misfire. An 8 to 10
percent reduction in one fuel
injector can cause this to occur.
Dirty fuel injector
Clogged fuel injector
Fuel injector does
not open
Uneven Engine
Idling
An engine should idle smoothly,
but an uneven fuel supply will
cause idling disturbances.
Dirty fuel injector
Fuel Scent
Leaking fuel from a faulty fuel
injector will create a strong
gasoline smell.
Fuel injector does
not close
Fuel injector leaks
Diminished Gas
Mileage
A fuel injector that delivers drops
of gasoline instead of a mist will
make for inefficient use of the gas,
reducing the car's gas mileage.
Fuel injector does
not close
Fuel injector leaks
Being able to observe these symptoms is an important aspect of realizing that
there is a problem with a car, and being able to associate these symptoms with
specific fuel injector problems will help car owners to resolve the issues with
their injectors quickly.
RUN DIAGNOSTIC TESTS
This section describes a few tests that owners can run to help them to diagnose
fuel injector problems. These tests are relatively simple, though they do
require accessories to complete them.

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 Measure Exhaust Manifold Temperatures
If a fuel injector will not close, it will dump gasoline on the catalyst that
opens and closes the valve, causing it to overheat and burn out. This will
produce high temperatures at the exhaust manifold while the engine is
warm. If the valve will not open, an excessive amount of oxygen will
disable the catalyst, producing excessively low temperatures at the
exhaust manifold. To determine whether this is an issue, point a laser
thermometer at the pipes of the exhaust manifold while the engine is
warm. A normal reading on each cylinder will be within 30 degrees of
450 degrees Fahrenheit. An injector that will not open will yield a
temperature of 200 to 250 degrees and an injector that will not close will
show temperatures of 600 degrees or more.
 Listen to the Fuel Injectors
Another helpful diagnostic tool is an engine stethoscope. This tool
enables a car owner to listen for any problems with the fuel injectors by
placing the tip of the stethoscope on each injector. Fuel injectors make
a sharp clicking sound when they are functioning properly, so the
absence of this sound can indicate a problem with an injector.
 Inspect the Fuel Injectors
A third way that car owners can diagnose their cars' fuel injectors at
home is by removing the fuel injectors and inspecting them. Start by
detaching the fuel rails to which the injectors are likely attached. After
removing the rails, detach each fuel injector from each rail. Fuel will flow
from the rails as each injector is removed, so be sure to wear gloves
during this process. After removing all of the fuel injectors, inspect each
one for signs of cracks or damage to any of the parts within the injectors.

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MAINTENANCE OF PETROL ENGINE
A petrol engine (known as a gasoline engine in American English) is an internal
combustion engine with spark-ignition, designed to run on petrol (gasoline) and
similar volatile fuels.
In most petrol engines, the fuel and air are usually pre-mixed before
compression (although some modern petrol engines now use cylinder-direct
petrol injection). The pre-mixing was formerly done in a carburetor, but now it
is done by electronically controlled fuel injection, except in small engines where
the cost/complication of electronics does not justify the added engine efficiency.
The process differs from a diesel engine in the method of mixing the fuel and
air, and in using spark plugs to initiate the combustion process. In a diesel
engine, only air is compressed (and therefore heated), and the fuel is injected
into very hot air at the end of the compression stroke, and self-ignites.

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TECHNICAL SPECIFICATIONS
TYPE 4 CYLINDER, VERTICAL, INLINE
BORE X STROKE IN MM 78 X 17.5
TOTAL DISPLACEMENT 1366 CC
MAX POWER (GROSS) 43.4@ 4600 RPM
(AS PER SAE-J-1391)
MAX TORQUE (GROSS) 7 KG.MK. @ 2800 RPM
(AS PER SAE – J – 1391)

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TOOLS AND EQUIPMENT:
 A kit of tools consisting socket
 Spanner Set
 Ring Spanners
 Double ended spanners
 Spark Plug Spanners
 Feller Gauge
 Combination Plier
 Nose Plier
 Circlip plier
 Piston ring clamp
 Bearing puller
 Screw Driver
 Mallet
 Steel Tray
 Brush
 Diesel Oil
 Cotton waster
 Clean rags
 Lubricating oil
 Grease etc.

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DISMANTLING PROCEDURE:
 Drain oil from the gear box.
 Remove the carburetor and put it in a clean tray.
 Loosen the spark plug with the spark plug spanner and keep it aside.
 Remove the cylinder head and cylinder block.
 Remove the magnet assembly with a special puller.
 Remove the clutch assembly.
 Remove the gear shifter.
 Remove the crankcase bolts, to have access to the crankshaft,
connecting rod and piston.
 Remove the circlips of the gudgeon pin and separate the piston from the
connecting rod small end.
 Remove the compression rings using ring expander.
 Remove the crank shaft bearing with the puller and remove the
connecting rod.

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MAIN PARTS
S.No. Name of Part Function Material
1. Cylinder Head It is a cover for closing one end of
cylinder and accommodates the
spark plug.
Aluminum
Alloy
2. Cylinder It acts as an enclosure for the air
fuel mixture for compression and
ignition, to liberate heat form
mechanical energy.
Aluminum
Alloy
3. Piston It is the reciprocating part in the
cylinder to suck, compress and
exhaust the charge and converts
pressure energy of the ignited
charge into mechanical energy of
the crankcase.
Aluminum
Alloy
4. Piston Rings These prevent the leakage past the
piston and cylinder wall.
Cast Iron
5. Gudgeon pin It acts an inter link between piston
and small end of connecting rod.
Case
Hardened
steel or
Alloy Steel
6. Connecting Rod It acts an inter link between piston
and crankshaft to transmit the
mechanical energy of the piston to
the crankshaft.
Alloy Steel
7. Crankshaft It converts the reciprocating
motion of the piston received by
the connecting rod into rotary
motion.
Alloy Steel
8. Flywheel cum
Fan
It provides energy to the piston to
perform power consuming
operations i.e. suction,
compression and exhaust.
Aluminum
Alloy
9. Main Bearings These act as a support for the
crankshaft between the crankshaft
and the crank case by providing
needle bearing or ball bearing.
Steel

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10. Spark Plug It ignites the compressed charge of
air fuel mixture with the help of
spark produced between the
electrodes.
Central
electrode
enclose
with
porcelain
insulation
and steel
body.
11. Ignition System It consists of magnet assembly
having primary coil, secondary coil,
CB Points, ignition coil and
permanent magnet to produce the
high tension current to ignite the
mixture of air fuel.
Steel
magnet
copper
winding of
coils with
aluminum
condenser
12. Carburetor It is a device to mix air and fuel in
proper ratio and supply to the
cylinder at proper time.
Aluminum
body gun
metal
13 Air Cleaner It removes dust and dirt from the
incoming air.
Jets
Perorated
paper
14. Gear Box It consists of clutch assembly shaft,
main shaft and cluster assembly for
power transmission to the wheel.
Steel

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COMMON FAULTS IN PETROL ENGINE
ENGINE DOES NOT START: It may be due to:
 Discharged battery
 Cracked distributor cap
 Pitted and dirty contact breaker points
 Insufficient gap of contact breaker
Rapidly burning of the breaker points: It may be due to:
 Condenser not earthed properly
 Condenser defective
 Oily breaker points
 Points gap too small
 Weak breaker arm spring
 Excessive generator voltage
SPARK PLUG FAILURE: It may be due to:
 Incorrect plug – gap
 Poor ignition and too much carbon deposited in the plug.
 Burned plug electrodes
 Plug produces poor spark
ENGINE MISFIRES AT HIGH SPEEDS: It may be due to:
 Coil or condenser defective
 Point gap too little
 Worn – out breaker plate assembly
 Breaker points bounce

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HOW TO DIAGNOSE CARBURETOR PROBLEMS
Before attempting to fix a carburetor problem, it is very important to come up
with the correct diagnosis.
Carburetors are relatively simple devices. Their primary function is to
deliver the correct amount of fuel/air mixture at a given throttle opening (as
selected by the rider). However, as with all mechanical devices, carburetors will
wear over time and will also require periodic tuning and service.
Carburetor problems generally fall into three areas: rich mixture, lean
mixture, and incorrect adjustment. Diagnosing carburetor problems is relatively
easy and follows some telltale symptoms.
THREE CARBURETOR PROBLEMS
 RICH MIXTURE means the carburetor is delivering too much gasoline.
Typical symptoms of a rich mixture are:
 Poor fuel economy
 Sluggish acceleration
 Choke not needed from cold starts
 Sooty or black spark plugs
 Sooty or black muffler end pipes
 Strong smell of gasoline when machine is at idle

31
 Uneven running (will often slow from regular idle rpm's and stop)
 LEAN MIXTURES means the carburetor is delivering too much air. Typical
symptoms of a lean mixture are:
 Backfires as the throttle is closed (primarily during coast-downs)
 Lurching acceleration
 White or light grey spark plugs
 Requires excessive amounts of choke to run/start
 White or light grey muffler end pipes
 Bluing (on chrome systems) of the exhaust header down-pipes
 INCORRECT ADJUSTMENT applies to carburetors that have incorrect
adjustment of the air/fuel screw and the balance between two or more
carburetors - where fitted. Incorrect adjustment can produce any of the
previously noted symptoms. On multi-cylinder machines, with separate
carburetors for each cylinder, the following symptoms are typical of an
adjustment problem:
 Poor overall performance
 Rattling sounds from the clutch
 Engine tends to stall easily
 Erratic acceleration
 Poor fuel economy
 Misfires and/or backfires
CORRECTING CARBURETOR PROBLEMS
LEAN MIXTURES: This condition is generally caused by the owner fitting after-
market accessories such as exhaust systems, air filter systems or replacement
carburetors of a different type or size. In addition, if the fuel level in the float
chamber is set too low, insufficient fuel will be drawn through the main jet.
Some carburetors have a slow speed fuel adjusting screw that regulates the
fuel/air mixture in the lower rpm range.
RICH MIXTURES: This condition is primarily caused by dirty air filters, but it could
also result from the owner fitting replacement exhausts and/or carburetor
systems. If the fuel level is set too high in the float chamber, a rich mixture will
result.

32
Incorrect Carburetor Adjustment: This situation is mostly caused by poor
maintenance. With the inherent vibration of all engines, carburetor parts
(primarily adjusting screws) tend to rotate, and therefore change their positions.
Low-speed running jets and multi-cylinder balancing screws are the items most
prone to self-adjust during normal operation and often require periodic
corrections.

33
SYMPTOMS OF BAD OR FAILING SPARK PLUGS
Common signs of faulty spark plugs include slow acceleration, loss of power,
poor fuel economy, engine misfires, and difficulty starting the car.
Without a spark, there would be no way for fuel to ignite in the combustion
chamber. Spark plugs have been a critical component of the internal combustion
engine for years. Spark plugs are designed to transmit an electrical signal sent
from the ignition coil at a predetermined time to create a spark that ignites the
air-fuel mixture inside the combustion chamber. Each vehicle requires a
particular type of spark plug made from specific materials and with a designated
spark plug gap that is set by a mechanic during installation. Good spark plugs
will burn fuel efficiently, while bad or failing spark plugs can cause the motor not
to start at all.
 SLOW ACCELERATION
The most common cause of poor acceleration on most vehicles is a
problem in the ignition system. Today's modern engines have multiple
sensors that tell the onboard computer and ignition system when to send
electric pulses to fire the spark plug, so the issue may be with a faulty
sensor. However, sometimes the issue is just as simple as a worn out spark
plug. A spark plug is composed of materials that work together in order to
produce a spark hot enough to ignite the air-fuel mixture. When those

34
materials wear out, the effectiveness of the spark plug is reduced, which
can significantly reduce the acceleration of the vehicle. If you notice that
your car is running sluggishly or does not accelerate as quickly as it used
to, it may be attributed to a spark plug that needs to be replaced.
 POOR FUEL ECONOMY
When a spark plug works correctly, it helps burn fuel efficiently in the
combustion cycle. When this occurs, your car can achieve better than
average fuel economy. When the plug is not functioning optimally, it is
frequently due to the fact that the gap between the spark plug electrodes
is either too close or too far apart. In fact, many mechanics will take out
spark plugs, examine them, and adjust the gap to factory settings as
opposed to replacing the spark plug entirely. If your vehicle has a
reduction in fuel economy, it very well could be attributed to a worn out
spark plug.
 ENGINE IS MISFIRING
If the engine misfires, it's typically due to an issue in the ignition system.
Most of the time in modern cars it's due to a sensor malfunction.
However, it may also be caused by a spark plug wire or the tip of the spark
plug that connects to the wire being damaged. An engine misfire can be
noticed by intermittent stumbling or sputtering sounds from the engine.
If the engine is allowed to keep misfiring, exhaust emissions will increase,
engine power will decrease, and fuel economy will drop. Because of all
the potential problems associated with engine misfiring issues, you
should contact a mechanic as soon as you notice an engine misfire.
 DIFFICULTY STARTING THE VEHICLE
If you have trouble starting your vehicle, it could be a sign your spark plugs
are worn. However as noted above, the engine's ignition system is
comprised of multiple individual components that must work cohesively
in order to function properly. At the first sign of problems starting your
car, truck or SUV, it's a good idea to contact a certified mechanic to take
a look at the cause.

35
Regardless of what the issue might be, the reality is that spark plugs will
eventually wear out. Being proactive about spark plug maintenance can extend
the life of your engine by hundreds of thousands of miles.

36
SYMPTOMS OF A BAD OR FAILING DISTRIBUTOR ROTOR
AND CAP
Common signs include engine misfires, car not starting, the Check Engine Light
coming on, and excessive or unusual engine noises.
A running engine sends a large amount of electricity through the ignition coils
to the rotor, which turns inside the distributor. The rotor routes the energy in a
specific through the spark plug wires ultimately to the engine’s cylinders in the
correct firing order.
The distributor rotor and cap keep the distributor’s contents separate
from the engine and keep the distributor’s working parts clean and tidy – while
supporting the incredibly high volts of energy and delivering them to the
appropriate spark plugs. The spark plugs utilize the spark from the distributor to
ignite the fuel mixture, which is what keeps the engine running.
High voltage runs through this entire distributor system during the
operation of your vehicle, but if there's an issue this voltage won’t get
distributed to the correct spark plugs to ensure that your engine will run. Usually
a faulty distributor rotor and cap will produce a few symptoms that alert the
driver that service may be required.
 ENGINE MISFIRES

37
Engine misfires can occur for a number of reasons. Checking your
distributor rotor and cap to see if they need to be replaced is one way to
ensure that everything is in solid working order.
 CAR DOESN’T START
When the distributor cap isn’t on tightly or is malfunctioning, the engine
is unable to send the spark through the entire circuit required to move
the cylinders – which ultimately make the car run.
 EXCESSIVE OR UNUSUAL ENGINE NOISES
Your vehicle may make some very strange noises if the distributor rotor
and cap are malfunctioning – specifically because the cylinders will try to
fire but fail. You might hear a tapping, clicking, or sputtering sound when
the distributor rotor and cap are failing.
Any time you have routine service performed on your vehicle, ask that the
ignition system be checked for defects or problems.

38
PROPER FIRING ORDER OF A 4 CYLINDER ENGINE
The typical firing order of Inline four cylinder engine is 1-3-4-2. Firing order in a
multi-cylinder engine is arranged so that the torsional moment is even and the
load is uniformly distributed on longitudinal direction of the crankshaft. An even
firing order will increase the balance of engine.
A 4-stroke engine completes four strokes while crankshaft rotates 2 times.
For a four cylinder engine hence an even firing should happen every 180 degree
rotation of crank.
The following principle should be considered, in spacing out the firing
 The combustion should not occur simultaneously in two or more
cylinders;
 Successive combustion in the cylinders that standing side by side should
be avoided so that the force transmitted to the crankshaft does not
become one-sided.

39
COST ESTIMATION
Diesel Engine
Sr. No. Component Name Cost (INR)
1. Diesel 150
2. Injector 50
3. Oil Pump 100
4. Fuel Pipe 50
5. Rocker Box 380
6. Diesel Filter 225
7. Gaskets 20
8. Injector Washer 5
10. Exhaust Elbow 70
11. Oil Paint Varnish 40
12. Thread 10
13. Flexible Exhaust Pipe 150
14. M-seal 20
Total ₹1270
PETROL ENGINE
Sr. No. Component Name Cost (INR)
1. Petrol 250
2. Spark Plug 200
3. Plug Cap 80
4. Battery Water 30
5. Air Filter 10
6. Engine Oil (3.5L) 700
7. Battery Terminals 60
8. Petrol Oil Filter Service 50
9. Self-Start 400
10. PVC Tape 10
11. Clamps for cooling 75
12. Professional Help 900
13. Gear Oil (3L) 670
Total ₹3435

40
Transportation Cost ₹300
General Utilizing Material
Sr. No. Item Cost (INR)
1. Soap 20
2. Fevi Quick 20
3. Electrodes 30
Total ₹70
Total Cost
1. Diesel Engine 1270
2. Petrol Engine 3435
3. Transportation Cost 300
4. General Utilizing Material 70
Total ₹5075

41
CONCLUSION
Our project “Maintenance of Diesel and Petrol Engine” has been successfully
completed. The deep maintenance project brought together resources from
every corner to participate in some way however large or small. This in itself
could be seen as the greatest success factor in the project. Every person who
participated in the project gained valuable knowledge on the issue of diesel and
Petrol engine maintenance that so many continue to believe to be a non-issue.
At the end of the project it is clear to all of us who participated that improved
maintenance practices on diesel engines is the first line of control to reductions
in emissions. To simply re-state the objectives of the project and how the work
has achieved success on each point would be further repetition of what would
by now be obvious. The final judgement should be left to those who actually did
the work with this project and continue to carry on with the monitoring of
emissions and practicing improved engine maintenance long after the project
has been completed. During the case studies in the project the mechanics were
asked to provide feedback as to their thoughts on the new maintenance
practices and the future.

42
REFERENCES
The Project Idea
Project Queries Er. Parul Dhiman
Others:
 www.google.com
 www.mechprix.com
 www.wikipedia.com
 Encyclopedia
 V. Ganeshan (2007). Internal Combustion Engines. New Delhi: The Mc
Graw Hill
 Willard W. Pulkrabeck. Engineering Fundamental Of The Internal
Combustion Engines. New Jersey: Prentice Hall.
 John B. Heywood (1998). Internal Combustion Engine Fundamentals. The
Mc Graw Hill Series.

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