Wednesday, March 20, 2013




a. Background

                Developments in science and technology (Science and Technology) is rapidly increasing nowadays have an impact on the world of education with the growing challenges faced by the world of education. Now the world of education is increasingly required to produce qualified human resources, which is able to answer and anticipate developments in science and technology. The world of education should be able to make it happen, it is necessary to increase and improvements in education. One effort peningakatan and improvements in education especially in the field of automotive engineering in particular, one engine stand Diesel Mitsubishi L 300. Mitsubishi L 300 is the type of vehicles manufactured by Mitsubishi Diesel type, while the Mitsubishi L 300 stations in the book there is an additional GS (gasoline) that Mitsubishi L 300 GS (Mitsubishi L 300 types of gasoline). Engines Mitsubishi L 300 in which there are several systems, among other energy-producing drive systems or the engine (engine), fuel system, lubrication system, cooling system, charging system and the system of the engine (engine). This paper will explain how the later analysis and how to cope with reduced engine power on Diesel Mitsubishi L 300, especially on the engine (engine). Other things the background for the selection of the matter is: The machine system is very important in the work process, propulsion and energy production in a vehicle or car. The machine consists of several components, if any one of the components undergo wear and tear or curvature caused by the heat work and then there will be an interruption in engine power is reduced as caused by several reasons such as worn piston rings, cylinder head and cylinder block surfaces are curved
causing the gas leak and the engine power produced less than optimal.
b. Formulation of the problem

Why is the engine system is very important in the process of work, drive and energy production in a vehicle or car?
c. Destination


Working Principle Motor Diesel

    Motor fuels are of two kinds, namely combustion engine (internal combustion angine) and external combustion engine (external combustion engines), examples of external combustion engine (external combustion engine) is a steam engine, turbine and other machines, eg combustion engine (internal combustion engine) is a Diesel motors, motor gasoline, and others. Type of car or vehicle is based on the combustion mechanism used divided into two diesel motors and motor gasoline (internal combustion engine). Diesel engine combustion mechanism known as compression ignition. The fuel is compressed until the pressure + 25 s / d 32 kg/cm2 (Daryanto: 1995) in order to reach the point of ignition and fuel burn by itself, while the gasoline engine using spark ignition mechanism. Fuel pressure until a certain pressure is: + 15 s / d 22 kg/cm2 (Daryanto: 1995) and then given a spark from the spark plug firing order terjadiproses. Diesel Motor use diesel fuel in addition to its use more efficient, diesel fuel is also more environmentally friendly because the solar mixture of lead (lead) that cause pollution and respiratory disturb less than gasoline motors, but because xxi pressure ratio compression ignition mechanism very high and require a more robust construction, in general, the price of cars by using Diesel engines are more expensive than the car using gasoline motor for the same class. The wheels of a vehicle requires a power which allows the vehicle to move, and can cope with the situation, the air, and so forth. Sources that generate power are called machine .. combustion engine piston is the name of the machine that can convert thermal energy, electricity, wind or other power source into mechanical power. Engine that converts heat energy into mechanical energy is called motor fuel. Engine (engine) used in automobiles, is one of a series of components (system) is very important that as a system that converts the heat generated from the combustion process is then converted into work through the mechanism of translational motion straight back and forth (reciprocal) of the piston ( piston) into a rotary motion (rotation) on the crankshaft
(Cankshaft). Machines energy used in the car to be compact, lightweight and easy to put on limited space. Machine shall provide a high speed and power are great, easy to operate and is less of a sound, and therefore gasoline and Diesel engines are generally more widely used in the vehicle or car.
Advantages Diesel engines than gasoline motors in general:
a. Diesel engines have a large thermal efficiency, this means that the use of more fuel economical than gasoline motors.
b. Diesel engines are more durable and do not require an electric ignition (Electrik Igniter) to support combustion so less difficulty than the gasoline motor.
c. Speed ​​is lower than gasoline motors.

Diesel motors disadvantage compared with the gasoline motors
a.Tekanan nearly twice the maximum burning gasoline motor 25 s / d 32 kg/cm2 (Daryanto 1995), it causes vibration and sound bigger Diesel motors.

b.Tekanan higher combustion, the diesel engine must be made of materials that resist high pressure and the structure of the material is more powerful, it causes vibration and structure stronger material, this led to the making to be more expensive than gasoline motors.

c.Motor Diesel fuel injection systems require precise causes are expensive and require careful care and maintenance than gasoline motors.


A. STEP Suction
In step suction, air is introduced into the cylinder. Plunger (piston) evakuman in cylindrical form as in motor gasoline. Plunger (piston) moves from top dead point towards the bottom dead point and at this stage only the suction valve opens and allows air into the cylinder and exhaust valves are closed during this suction action.

In the compression stroke, the piston (piston) moves from bottom dead point towards the top dead point, and at the compression stroke is the second valve is closed. The air is sucked during suction pressure to step up the pressure with a temperature of about 5000 C to 8000.


In step combustion, the air contained in the cylinder is driven by a piston (piston) into the combustion chamber at the top xxiv each cylinder, at the end of step nozzle spraying burning fuel and then a mixture of fuel and air later burned by the heat pressure generated by the heat generated by the combustion energy mengekspansikan pressure gas very quickly and plunger (piston) pushed down. The force pushing the plunger (piston) to be forwarded to the shaft bottom (connecting rod) and then forwarded to the crankshaft (crankshaft) and the change from a straight back and forth motion of translation into
rotary motion (rotation) untukmemberi power on the machine.


In step exhaust, piston head from the bottom dead point towards the top dead point. In this step only the exhaust valve opens and the exhaust combustion gases expelled through the exhaust valve. Gas will be spilled out when the piston (piston) reaches top dead point, once the process begins again step step waste suction, and so on. This process occurs over and over again. During the machine, completing the four steps (steps suction, compression, combustion, exhaust) crankshaft (crankshaft) spins twice and produced a one-time combustion (power), or also called Diesel four-stroke motors.


                Disturbances such as low compression, will lead to lower work ability of the engine causing the engine power is reduced, so it is necessary to find the cause angguan-tersebut.Analisis disorders cause reduced engine power interruption:
A. Valve leakage during the compression stroke as well as businesses move or low compression pressure with air or smoke coming through the gap between the cylinder head and cylinder block and
air (smoke) out through the gap between the cylinder head gasket, due to:
1). In the cylinder head:
-Leaks compression caused by the curved surface of the cylinder head, which caused:
A) Heat engine due to compression pressure is very high and continuous use of the machine can cause the surface of the cylinder head changes shape or curved, to overcome by redistributing surface cylinder head by means frais, if it can not be repaired due to high cylinder head has been reduced the cylinder head must be replaced with a flat and the height of the cylinder head is still in the specification or metal coated cylinder head to cylinder head thickness exceeded specifications of + 1 to 2 mm and then at frais.

B). Gasket between the cylinder head and cylinder block that is damaged or leaking gas burning out, which is caused by:
a.Pemakaian machine continuously and high compression pressure and the location of the gasket between the combustion chamber causing reta-cracked or broken so that the compressed air leaks out.

b. Demolition of the former engine gasket damaged and not replaced when the part of the gasket there is glue on the cylinder head and cylinder block so that the upper or lower surface of the gasket was reduced due to previously installed very fast and pengencangannya using a key moment, to deal with is the gasket replaced with a new one.

2) The valve mechanism:
Compression pressure and low noise with the valve mechanism. This condition is caused by several things, including the following:

2.1.Celah suction and exhaust valves are too big. Cracks due in large valves:
a) There is wear on the field up and down on the top of the ridge axis clearance or gap between the lifter cam shaft lxiii loose causing angle valve opening and closing the valve to be small.
b) The voltage of the valve spring is weak, which causes the valve can not be returned to the
perfect gap and cause the valve to be great.
c) The end of the valve stem is not flat, worn or damaged. This condition is due to the suction valve is too large then
 suction valve opening becomes shorter, resulting in a new volume of gas that enters the combustion chamber or cylinder becomes less so with the compression that uses a small volume will result in a smaller compression pressure resulting in reduced engine power, in addition to the combustion in the combustion chamber possible occurrence of abnormal combustion resulting from new gas flushing of gas combustion is not perfect. Compression pressure disertAai little noise in the cylinder head. Ganggguan other machines such interference is when the condition of the engine is in good condition and when the engine stationary noise sounded a regular on the cylinder head. This mechanical problem can be overcome by doing the checking and adjusting the valve gap. To check lxiv slit valve, open the cylinder head cover and insert a feeler gauge into the gap between the adjusting screw on the rocker arm and valve stems, then measure the gap when the slit valve is too loose, it can be
slit valve adjustment done.
 -On exhaust camshafts coated metal back that way: In welding, etc., then the shaft cam shaft cam turner or replaced with new ones.
-The length and spring tension should be checked with the valve spring tester, if voltage is less than the length and then spring weak specification should be replaced, because the weak valve springs can not lift the valve completely then opening the valve becomes less and gas
that enters the combustion chamber a bit.
-Edge digrinda valve stem, if the height is less than the specification of valve valve replaced.

2.2.Celah suction valves and exhaust valves are too tight, I fix the valve set appropriate specifications. This condition is caused by several things, including the following:
a) Cam ridge on the shaft is worn.
b) improper valve adjustment.
c) end of the valve stem is not flat, worn or damaged.

The gap between the end of the valve stem to rocker arm adjusting bolt should be there, when there is no loopholes valve the valve can not close tightly against the valve seat. So that the gas is in the cylinder chamber can not be compressed as compressed gas before (TMB-TMA) most gas comes out through the valve so that the vacuum in the combustion chamber or cylinder is reduced. Disorders slit valve on the machine can be done by adjusting the slit valve rocker arm bolts. How to overcome the valve is too tight:
a) Cam digrinda specifications or cam shaft replaced when wear exceeds the limit.
b) Valves are set to specification 0.25 mm suction valve and exhaust valve 0.25 mm.
c) The end of the valve stem digrinda and if the length of the valve stem is less than the specification changed.

2.3. The leak at the intersection of the surface of the valve head to the valve seat.
The leak was caused by the surface of the valve and the valve seat is not flat so persinggungannya LXVI persinggungannya not meeting density, caused by pemakaiandari engine constantly and the influence of heat, because the head is inside the fuel valve or compression chamber and beat the return valve after the valve opening from the valve spring causing some parts there are terkikis.Kepala eroded valve could be improved by improving the surface of the valve head with valve refacer or by disekur between the surface of the valve with the valve seat. Wear or damage to the valve and valve seat when exceeding the limit then one or both must be replaced.

2.4. Rubber seal on the valve is damaged or worn,
Rubber seal on the valve is damaged or worn so that the lubricating oil that lubricates the cylinder head down to the valve and down into the combustion chamber through the valve head. The gap between the valve stem and the valve seal is worn, this condition causes a charcoal on the valve stem and to overcome the inherent charcoal valve head is cleaned using a wire brush or wire wheel mounted on the grinding machine. Seal worn replaced because it is made of rubber.
2.5. Conductor valve is damaged or worn
Conductor valve is damaged or worn so that the lubricating oil that lubricates the cylinder head down to the valve through the valve conductor worn, this condition causes the valve stem timbulpada and to overcome the inherent charcoal valve head is cleaned using a wire brush or wire wheel mounted on grinding machines, then conductor of worn valve replaced.
- The engine components:
1. Slit or spring-loaded piston ring against the cylinder walls are too wide. This condition is caused by:
 spring piston or piston ring is already weak due to continuous usage and friction resulting in a gap between the end of the spring piston causes compression leak widened and also resulted in the lubricating oil of lubricating oil pan (charter) into the fuel, to overcome a spring piston or piston ring is weak replaced with a new one because if it is not replaced piston ring end gap widens between the causes compression and lubricating oil leak
into the combustion chamber or cylinder.
2. Cylinder has an oval-shaped hole or worn. This condition is caused by: the use of continuous and friction between the piston and the cylinder wall so that the heat and cause expansion, so there is a gap on one side of the cylinder wall and piston ring causing panic in from the lubricating oil lubricating oil (charter) into the combustion chamber and peyebabkan compressed air will leak, how to cope: a cylindrical hole in shock that the metal coated cylindrical hole is drilled or a turner then the size of the diameter of the cylinder and the cylinder bore enlarged if the piston ring used must be adapted to the diameter of the cylinder wall.
-Engine power is reduced due to wear and tear experienced some engine components such as piston ring wear, piston wear, worn cylinder walls, causing the lubricating oil of lubricating oil pan (charter) to the combustion chamber is:

1. On the exhaust (muffler) out a little white smoke colored machine with reduced lubrication of lubricating oil in the system and the smell of burning lubricating oils (lubricating oils wasteful consumption) that cause air pollution and interfere with breathing. The entry of lubricating oil into the combustion chamber exhaust mangakibatkan white. Inspection performed on your vehicle engine components such as cylinder walls, piston rings, piston due to wear and tear resulting from the use of vehicles and the result of ongoing friction that causes such wasteful use of oil that is there most of lubricating oil into the combustion chamber through the piston. Lubricant can also go into the combustion chamber through the streets experiencing valve wear. Lubricating oil into the combustion chamber it difficult fuel to burn, causing power or engine power is reduced. Burning of lubricating oil in excessive amounts result in sediment or crust on the piston and combustion chamber walls, to overcome this problem, the steps you need to do is replace the piston and piston rings. Cylinder wall already
experience wear or scratches the cylinder wall is replaced with a new one.
2. Knocking sound from the engine (knocking), heard at the time was accelerated. knocking sound from the engine (knocking). Knocking is caused by a lot of carbon in the crust of the combustion chamber or cylinder. Carbon crust formed by oil entering the combustion chamber or cylinder caught fire. The crust of carbon in the combustion chamber or cylinder co burned during combustion occurs. Carbon crust can increase the temperature and pressure at which resulted in knocking combustion. The entry of oil into the combustion chamber is due to the combustion chamber components, such as piston rings, cylinder walls are worn due to constant use and due to friction. Carbon or charcoal crust that is inside the combustion chamber (cylinder) can be solved by replacing the LXX components that cause the lubricating oil into fuel or worn parts such as piston rings, cylinder bouring and others. The components of the experience such as piston ring wear, cylinder bouring can



Disorders that often arise in Diesel Mitsubishi L300 engine, including reduced engine power can be obtained conclusions include the following:

1. How to analyze the disorder and how to cope with reduced engine power on the machine Mitsubishi L 300 Diesel is by doing the inspection and corrective action is then performed to specification or the replacement of parts or components when damage
exceed the specified limit.
2. Inspection procedures and component repair if engine power is reduced at Mitsubishi L 300 Diesel is a visual inspection as observed scratches on the cylinder walls and measuring devices by measuring the condition of each component based on the specifications service, followed by step repair or replacement of components when damage exceeds the service limit. From the results of visual inspection and measurement, there
components in the engine Mitsubishi L 300 Diesel have to be replaced or repaired.


Arismunandar,Wiranto,Tsuda,Koichi.1997.Motor Diesel Putaran Tinggi.Jakarta : PT Pradnya Pratama.
Boetarta,2000,Mengatasi Mesin Kerusaan Diesel.Jakarta: Puspa Swara
Daryanto ,1994,Teknik Servis Mobil.Jakarta:Pt Reneka Cipta.
Dermana,danu ,1999, Merawat dan Memperbaiki Motor Diesel.Jakarta: Puspa Swara



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