Before to start working with the engine you should make sure that you have a proper manual. Online manual from ALLDATA is very good information material. The engine can be viewed as a heart of a vehicle which pumps air and fuel instead of blood. All engines are design to convert fuel and air into rotary motion in order to drive car’s wheels. How is this achieved? Pistons. They move up and down in the cylinders. Most cars have four, six or eight pistons. The so called combustion chamber is placed in the upper side of the piston. Here the fuel and air are getting mixed before being ignited. Crankcase full of oil is situated on the other side of the piston. There are ring provided in pistons which prevent oil from getting into the combustion chamber and fuel and air from mixing with the oil. Pistons are made from lightweight aluminum and they are moving in the cylinders without touching their walls moving on a thin oil layer. In the event the rings are damage oil gets into the combustion chamber which results in grey smoke coming out of the exhaust. In this case the pistons can score the cylinder walls damaging the engine which leads to a serious repair. Crankshaft. Through the connecting rod the crankshaft is connected to the pistons. As the piston is floating up and down in the cylinder it rotates the crankshaft thus converting straight line motion into rotary one. Valvetrain. It consists of valves, arms, rocker, pushrods, lifters and cam shaft. The fuction f the valvetrain is similar to that of a traffic cop. It lets air and fuel in and out of the engine in a proper time. The camshaft being synchronized with the crankshaft by the chain or belt controls the timing. These are the main parts of the engine and now you have an idea of their work. Now we are going to give you an idea of what is going on in the engine during its normal operation. Today most modern cars have four-stroke (four-cycle) engines. The cycle of their action consists of four distinct events. A complete cycle of four-stroke engine has two crankshaft revolutions. The 4-stroke cycle consists of the following events: Intake stroke. The intake valve is opened by the camshaft and the piston is moving down the cylinder. Compression stroke. The piston is moving back up the cylinder and makes the intake valve close. Thus the combustion chamber is sealed off. The fuel and air are getting mixed. Power stroke. When the pistol is already near the cylinder top and the fuel is compressed this mixture is ignited with spark plug. The piston is pushed back down the cylinder by the explosion and the crankshaft is driven. Exhaust stroke. When the piston is approaching the cylinder’s bottom, the exhaust valve opens and the gasses go out through the exhaust system. So the four events mentioned above and taken together make a complete cycle. Are you sleeping now because you are tired of bare theory? We had to tell you all these boring things to give you a general idea of engine’s work. In the following part of the article we’ll talk about the real problems you can have with al the parts mentioned above.