An engine is composed of several major components; the block, the crank, the rods, the pistons, the head (or heads), the valves, the cams, the intake and exhaust systems and the ignition system. These parts work together in an exacting manner to harness the chemical energy in gasoline.
The engine block consists of a cylinder block and a crankcase. An engine block can be produced as a one-piece or two-piece unit. The cylinder block is the engine component that consists of the cylinder bore, cooling fins on air-cooled engines, and valve train components, depending on the engine design.
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