All the major components like cylinder blocks and engine blocks of a diesel engine are made of cast iron. Diesel engine whether 4 strokes or 2 strokes works on the principal of internal combustion and are exposed to higher operating temperature, therefore all parts are made of heavy material. Following are some major component useful for internal combustion of diesel engine:
1. Carburetor: Use to supply fuel to engine.
2. Fuel injection: Use to initiate and control the combustion.
3. Fuel pump: Delivers time injection directly into combustion chamber.
Where core parts of a diesel engines are:
1. Valve: Use for admittance of fuel into combustion chamber.
2. Piston: Transfer the expanding gas from cylinder to crankshaft.
3. Crankshaft: Converts the inline motion of piston
You can also visit any diesel engine dealer site like http://www.buyusedengine.com/#tabs-1 or any tutorial site, so as to know more.