2 stroke engins

HOW DOSE A TWO STROKE ENGIN WORK?

a two cycle works alot diffrently to a 4 stroke system as the combustion happens through the whole block and the fuel and oil are mixed. a 2 stroke cycle works by drawing the fuel in through the inlet valve  and in to the crank casinging, on its down force the fuel is forced around the blosk and into the top of the block, the piston pushes back up compressing the fuel, the spark plug ignites the fuel sending the  piston on its down stroke and forcing the exhaust fumes out through the exhaust port. unlike a four stroke the oil stays in the sump and crank case to keep the  piston and cylinders lubricated, the fuel and air mix is let into the top of the boar by valves wich is then compressed and ignited by the spark plug. below the piston fuel and air is used to lubricate the crank and bearings, above the piston is were the combression and power comes from as it is were the fuel is ignited by the spark plug.  scavenging is  the revolution of the two stroke using the beginning of the compression stroke and the end of the combustion stroke.

BEARINGS

 special types of bearings need to be used in a two stroke  as using the same ones as a four stroke will seas becasue the oil is mixed with the fuel in a two stroke and needs a more inderpenit bearing. roller bearings and  closed case ball bearings are used as they are self lubricated and can circulate easy with out the need of oil to lubricate them.

weilding health and safety

SAFTEY EQUIPMENT
 overalls,steel caps,gloves (needed for certain types of weilding eg mig), goggles or weilding mask ( diffrent for diffrent types of weilding).

overalls or a weilding aprin must be worn as they prevent hot slag from burning your skin or clothing. the overalls must be made of cotten and not a papper based substance as they can catch fire easy. fluro or reflective overalls are best as they can be seen better than blue or black overalls.

steel caps are worn to prevent hot metal or falling objects from crushing your feet. wereing steel caps while weilding is important as hot heavy metal is more dangerous than just heavy metal.

FACE AND EYE PROTECTION

there are difrent types of face and eye protection for diffrent types of weilding.

gass weilding a tinted vision google is needed as the light from the weild is not as strong as on from a mig. the googles cover your eyes and have a spicific tinited vision to suit the gas weilding. for mig weilding you require a full weilding mask wich covers the front of your face and eyes. older masks have a tinted flap wich can be opened and closed so  you can see the weild or chipp away slag still being protected by a clear slip wich is mounted to the mask. new masks or auto dark masks have one open sheild mounted to the face mask that dosnt open or close. it is slightly tinted so u can see what your doing befor you weild but as so as the weild sparks the cover gose dark and is at a perfect darkness for weilding. when the weilding stops it gose light so you do noot need to remove the mask. auto dark masks are good if you weild alot.

WHEN WEILDING AND ENVIROMENT

before weilding there are sevral things that need to be checkeed before weilding. first check the are for famable materals eg petrol, diesel . remove matterals like this as sparks from the weilding can spark and explosing and cause fatil or seriouse harm. before weilding check the weilder and lines for cracks, splits or faults as  any imperfections or faults can cause a weak weild or can cause you ( the user harm). checking lines ,bottels and wiire feed. before weilding ennsure no one can see or will accidently look into the weild as this can damage there eyes. a weilding curtain should be set up to prevent the ar or light of the weild being veiwed by a passer by or member in the work shop.

health and safety

HEALTH AND SAFETY IN THE WORK SHOP

Steal cap boots, overalls, safety goggles are compulsory when using machines in the workshop. 

Boots need to be laced up tight so u cannot trip on the laces, roll your ankles  etc. wearing  the boots incorrectly can be more  dangerous then not wearing boots at all. Steel cap Boots are worn to protect your feet from falling objects that could break or crush your toes or feet. Used in a lot of workshops and workplaces.

Overalls are worn  to protect  your clothes and skin from swarf  hot objects, chemicals, grease and other substances which could be harmful to  your skin. Overalls should be worn correctly and not tied around the waste, zipped up for complete protection. Certain overalls are better than other others. Best overs for any workshop are reflective cotton overalls as they are easy to see, and not likely to catch fire unlike paper overalls. U can also get half overalls that don’t cover your arm which are still protective but not as much as full overalls.

Safety goggles are  a very compulsory in a work shop with machinery such as lathes grinders and drills which can throw out  hot swarf and wreak your eyes. There are several types  of safty goggles all that do the same thing.

Health and safety  in the work shop :

Lathe : tie up long hair, remove or tie up baggy clothing  eg  sleeves . removing or isolating these things can prevent  u getting caught in the chuck as its spinning. Being caught inside can cause serious damage if not death. Saftey glasses are to be worn at all times to protect your eyes from hot swarf from the lathe. Overalls and safety boots are also compulsory to wear as they protect your body and clothes from oil, swarf heavy or falling objects. Also  having knowledge on the machine before using it is health and safety  as knowing what it can and cannot do come be very dangerous if you don’t use the machine correctly.

Drills: tie up long hair, keep baggy clothing away from chuck and drill piece  as it can catch and pull u in to the drill  and cause u harm. Safety glasses must be worn as you only have  two eyes and swarf or hot pieces of metal  are  likely to be shooting out everywere. Overalls and safety boots must be worn to protect  your skin and clothing from swarf, oils or lube. Steel caps are needed as pieces of metal, drill bits or any heavy  or sharp objects could drop onto your feet .

Grinder:  ensure long hair and baggy clothing is tied back. Safety glasses must be worn as the grinder creates a lot of hot swarf and is highly dangerous without  safety glasses. Overalls and steel caps are needed also to protect your skin from the hot swarf. Either heat proof gloves or   vice grips  can be used to  hold on to the metal being grinded as it will heat up and sometimes can burn your hand making u let go of the material  causing further harm to the body. Dunking the material in some water or oil every so often helps with cooling the metal and makes it safer to work with.

 Hand tools:  files,  hack saws, taps and dies,  rulers, scribes, punches.

Steel caps should be worn if using any of these because if any of these feel off the bench on to ur foot it could cut or injure your foot. Safety glasses should be worn but  there is no need to. Overalls could be worn to protect your clothes from swarf or execs lubes or oils. Having basic knowledge of these hand tools will help with correct and safe usage of them preventing damage to your body.

First aid boxes are usually found bolted to the wall or in a special cupboard. People in the work shop should know where it is in case of emergencies.  Any injures should be reported in a first aid book to keep track of injures in the work shop so they can be prevented next time.

Fire extinguishers are usually found on the wall. Best to have one in the work shop in case of  fire. There are several types of extinguishers for different types of fires  e.g  chemical, electrical etc

 CLASS A: wood paper and plastics
CLASS B: flamable liguids eg petrol dieseil
CLASS C: flamable gases
CLASS D: combustable metals( magnisuim etc)
CLASS E: eletrical fires
CLASS F: fires involving cooking oils or fats

cooling!

INDERECT AND DIRECT COOLING

 inderect cooling on a boat is when the raw water or water from  sea or lake. the inderect part has a fillter wich fillters unwanted things like shells and seaweed from going into the engin. inderect cooling has coolant in the engin wich helps prevent corrosion or over heating  in the engin. direct cooling is were the sea water is pumped out of the sea into the engin and straight out. this direct cooling is not the best kind of cooling for a engin as the engin constantly has sea water in the water jackets and corrodes. in the cooling system of a boat there is a heat exchnger wich draws the hot water from the engin into the exchanger, raw sea water is circulating cooling the hot engin water, the end resault is the a cooler water us pumped out of the heat exchanger and back through the engin (inderect cooling) . direct is water pumped staright through the engin and staraight out for cooling.

PURPOSE OF A THERMOSTAT

the purpose of a thermostat is to alow coolant and water into the engin at a correct engin temp. without a thermostat the colant will just pump through constantly not alowing the engin to heat up to a correct running tempruture. thermostats can be tested by dunking them into heated water. boiling water to the temp of the manufacture specs, the spring should shut signing the flow off water.the thermosta is located on the side of the block linked to the radiator.

PRESSURE CAP

the pressure cap is ontop of the radiator and is used to alow coolant out of the reserve tank or pump coolant in . it is used under heat like the thermostat and opens and closese with the heat of the coolant.the pressure cap has its specs on the cap. u can test these just like a thermostat.

CORE PLUG

a core plugis from the manafacture of the block. because the block is cast iorn they need a place to poor the metal in. the core plug  also helps if the water or coolant frezzuse in the engin as u can remove the plug to c into the water jackets. core plugs have many names eg welsh plugs but all do the same job.



HEAT EXCHANGER

the heat exchanger is used in the cooling system of a boat. it used by drawing sea water into the barrel of the heat exchanger. this cold sea water or lake water cools down the engin water and coolant as it travells around the engin. the heat exchanger pumps out the hot sea/lake water out the water exhaust. the heat exchanger works as  cooling barrel and is needed on a inderect cooling engin. .

RAW WATER PUMP

 a raw water pump works by pumping sea water or lake water from under the boat up into the engin and or the cooling system. a raw water pump is needed in direct cooling as it needs to constanly pump raw water around the engin to keep it cool. in a inderect cooling system it is needed to draw raw water into the heat exchanger to cool down the coolant or water in the engin. not having a raw water pump would make it hard to cool the engin  ,would make it hard to draw raw  into the engin. the raw water pump may need replacing every once and while due to  sea water corrosion.

IMPELLER

 the impeller is a rubber rotar that sits in side the water pump that creates a vacum due to its shape and form.

this impeller helps with pumping the water and coolant around the engin to keep it cool. these umpellers need to be replaced as they can crack and harden removing there purpose of the vacum as there not as flimzye. it is important to lubricate a new impeller when instaling so that it turns and runs smothly  untill water and coolant is abble to lubricate it. not lubricating it can cause wear and tear on the new part and not fixxing the problem.when refiting the new impeller also check for chips or sharp edges that the impeller could rub on cause wear and tear.

OIL COOLER

the cooler is a small looking intercooler that is usd to cool the oil. having the oil being coold helps with the perfomance of the engin, helps with keeping the engin warm, and makes the oil in the engin last a bit longer.

INTERCOOLER/AFTER COOLER

a intercooler or after cooler is used on a turbo engin as it is needed to cool  the coolant and water  in the engin, the purpose of the intercooler is because of the bigger mass and size of it, the surface area that can be cooled by air . the intercooler has all these fetures that are alot better than a standerd radiator. running a standerd radiator on a turbo engin can cause the engin to over heat and runn sloppy.the intercooler/aftercooler works like a radiator but in a larger form. it pumps cold water into the engin, receves hot water from the engin, the water travels through the fins while being cooled by the air and back into the engin as it is coold down. after market stuff like nos rails can be installed to improve performance as it cools the liquid in the intercooller quicker.

INHIBITERS AND COOLANTS

 coolant is a must in a engin as it used to protect the water jackets, raise the boiling temp of the water in the engin and lower the frezzing temp in the water of the engin. coolant comes any difrent coulors manly in green. never mix to diffrent types of coolant as it can cause chemical  reactions in the engin causing damage.  depending on the enviroment  the engin is in depends on the amount of coolant mixed with water that gose into the engin. coolder enviroments need more coolant % to prevent the water frezzing in the water jackets. to test coolant you can use  hydometers or coolant testers. these messure the % of coolant in the mixed with the water.

diesel

dr rudolf desil was the creater of  the diesel engin, creating his first engin in 1893. although one like it was invented in 1890 by hornsbey and sons it wasnt fully functional as it had to have something to supply heat for a cold start and then that supplyer of heat had to be removed.

DIESEL PUMP

pressure from a diesel pump can range from 4-10 psi. the purpose of this pressure is so  that the diesel can be pushed through the injectors.a diesel pump works by running off one of the engin belts. the gear that runs off the belt is attached a a cam. the cam rotates and pumps the valves up up and down forcing fuel through the fuel lines creating a large amount of pressure.on a cold start there can be a primeror hand pump wich  manualy pumps desil into the lines creating that pressure for the combustion.the pump needs to be in time  as being slightly off or completely off can cause miss fireing, lack off fuel,  to much fuel basicly causing the engin not to run or run like crap.

GLOW PLUGS

glow plugs are used to heat up the fuel to a point were it dosnt ignite but easy to ignite with compresion. the heat up when the ignition is turned on, there is usualy a dash lite showing a coil, when that light gose out the glow plugs have heated up the fuel and it is ready to be turned over.they work by drawing the power from the battery. there is one for every cylinder and the srew into the side of the head near the injectors.to test if a glow plug works you can use jumper cables linked to the battery and attach them to the glow plugs.if they dnt heat up and glow at the end then then there faulty and need to be replaced. useing a volt meter can also test if they are working by messuring the voltage going to them.

LIFT PUMP

the lift pump on a diesel engin is used to pump the fuel from the gas tank to the fuel rail. it helps keep the fuel rail fill and supply the injectors with more diesel. having a lift pump wich was  made for a lower powerd diesel on a higher powerd diesel will cause a lack of diesel to the fuel rail reducing power and starving the engin of diesel.

FUEL SHUT OFF VALVE

 the purpose of the fuel shut off valve is to turn off and on with the ignition. when the ignition is turned on the fuel shut off valve opens and alows fuel to being drawn up the lines into the fuel rail and into the injectors. not having a shut off valve can cause the fuel to be constantly be pumped into the fuel rails causing a leak or miss use of fuel.

KNOCK SENSOR

the knock sensor is a knob like part that is linked to the engin, it sensors the knocking in the engin and sends that messege to the ecu.it also helps monitor the engins performance.the knock sensor helps look after the engin parts from damaging effects of engin knock.a bad or faulty knock sensor carnt regulate the engin properly causeing major damages.

DIESEL INJECTORS

unlike petrol injectors the diesel injectors have no electronic help. the diesel injector works of pressure built up in the injector. the fuel that  is drawn in from the fuel rail builds up around the outlet needle in the injector, when ther is a certian amount of pressure the fuel will spray out into  a pre chamber or a bowl for compression. the needle valve closes as the pressure re builds up for the next injection.

BLEEDING A DIESEL ENGIN

if replacing the fuel filter or removing the fuel rails or injectors the diesel engin must be 'bleeded' . to do this you lossen the injectors and crank the engin over, diesel will spray out so safty equitment will be needed. slowly tighten the injectors evenly ensure the engin is turned off and is only being turned over to check for leaks or if timing is complete. ensure the injectors are done up evenly and there are no diesel or air leaks when finished.

TURBO

a turbo works by sucking the exhaust fumes out of the boar an d doen the down pipe or exhaust.it pushes or blows the intake in quicker. having a turbo increases the horespower of a engin while not increasing to much weight. the turbo also needs a front mount or intercooler to keep the air cold in order to keep the engin at a decent running tempruture.having a turbo on a diesel engin helps with the performance of the engin.it helps more with compression cycle drawing exhust fumes out and helping with pumping more air into the boar. adding a turbo to a non turbo engin can cause issues and cut down its running life as the engin can have a lower or higher compression rate .having a low or high compressioncan make adding a turbo useless and expensive as pistons, cams,valves and all other engin core parts can breck quickly as they were not deigned to withold that kind of power from a turbo.

SUPERCHARGER

a supercharger is a air compressor used on forced induction of an internal combustion engin. the supercharer is attached to the crank shaft by a belt,chain or shaft. there are two types of supercharger, the former deliver that a fairly constant level of pressure increase of the engins rpm's, while the latter deliver  increses engin pressure with increasing engin speed.

the difrence between a turbo and a supercharger is that the  supercharger is run by a belt,chain or shaft as the turbo runns of the exhuats fumes. a supercharger is constantly orking as it is being run by the crank shaft were a turbo has its full power or kick when revs are high or rapidly increase.

AFTER-COOLER INTERCOOLER

having a after-cooler or a intercooler on a desil helps with the cooling down of the air and water. if the diesel is turbo the engin must have a intercooler to keep the engin in a decent or recomended running tempruture. because a diesel engin is a high compression engin itr is important to keep the water and air as cold as possible. keeping the engin cold also helps with performance and fuel usage.

COMMON RAIL AND STANDERD DIESEL

the difrence between the two is pressure and the injection system. the common rail has higher fuel presure than a standerd diesel, also the common rail is like a a petrol injection as the injection system is all done elctronicly running off the ecu. the standerd diesel injection runs off pressure and there is no eletricals involved.

THROTTLE BODY

the throttle body is located between the  intake manafold and air fillter tube. the pupose if having a throttle body is to controll how much air is being sucked into the intake manafold. it works when the throttle is opened either by foot pedal or leaver. the throttle body has a cable which is attached to the shaft holding the butterfly valve, on the attachment there is a re coil spring that recoils back when the throttle is wound off pulling the cable back and shutting the valve. on the side of  the throttle body is the tps switch whitch tells the computer (ecu)  how much open the throttle valve is so it can spray the right amount of fuel out of the injector .

 

FUEL RAIL

the fuel rail is located just above or beside the injecters.  the fuel rail is an import pipe that is used to supply the fuel injecters with fuel.  it is designed to have a pocket or seat in the rail wich holds the injecters as well as a inlet valve for the fuel line to supply the fuel.

FUEL PRESSURE REGULATER

the purpose of a fuel pressure regulater is to maintain a con stant fuel pressure above the intake manifold pressure.the presssure should be kept at the right mix with the manifold pressure to ensure a perfect spray of fuel to suit the air pressure being pumped through the maniflod.

INJECTORS

the purpose of a injector is to spray fuel into the air in the manifold just before the inlet valve into the boar. the injector runs off an eletric current from the ecu wich pulses leeting the  valve in the injecter open. the injector sprays the fuel, if the fuel is dribled or sprayed wrong it can contribute to a engin fault. the injectors are attached to the fuel rail and are scrud into the bottem end of the manafold near the block. the injector on a injection system is like a jet on a crab system as they are both supplying fuel at a controlled rate into the air mixtire for the combustion processe.

IDLE AIR CONTROLL

the purpose of an idle air controll is to keep the engin idling smooth. the engin ecu gives it the feed back it needs to keep the engin running at an aproprite idle speed. a faulty idle air controll can make it idle up and down and  and put strain on the engin.

o2 SENSOR

the o2 sensor is attached on the exhaust manafold as is used to tell the ecu or computer if there is to much oxogen in the exhaustr fuems. having a o2 sensor can let the computer know if the mixturs for combustion is to rich with oxogen. having this sensor go off means that there is either a faulty o2 sensor or there is an issue with the air intake.

,MAP SENSOR

map (manifold absoulte pressure ) sensor is used mostly on an injection system and  supplys instintanious manifold prssure. the purpose of a map sensor is to calculate the air density and  determins the engins mass air flow rate, wich then helps with the right amount of fuel to be sprayed out of the injetors and mix with the air for the perfect air fuel mixture for combustion.

PLENUM CHAMBER

the plenum chamber is used to distribute the intake  charge evenly and enhance engin breathing. the chamber is located between the throttle body and th runners of the intake manifold.

CAM AND CRANK SHAFT SENSOR

a crank and cam sensor is used to tell the ecu what position the carnk and cam is in for the igntion system. having a crank sensor helps to start the engin. the cam sensor wasnt on most of the old cars as it wasnt needed as the crank  was good enogh. having the cam sensor just helps the ecu with a little more information about what position the engin is in befor starting. the crank shaft is alos most comonly usedto read engin speed.

SINGLE AND MULTI INJECTION.

a sungle point injection system is used by spraying fuel into the air at the throttle body. the mulit point injection is sprayed in by the bottem of the intake manifold near the block. the single point is one injector spraying at the throttle body. multi poin has one injector for each cylinder, the injectors are mounted at the bottem of the intake manifold conected to the fuel rail wich supplys the injectors with fuel.so the diffrence between the two is were the fuel is  injected and how many injectors used.

EFI (electronic fuel injection)

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