PRINCIPAL ENGINE PARTS
Crankshaft. Power from the piston is transmitted through the piston pin and the connecting rod to the crankshaft, which transforms the reciprocating motion of the piston into rotary motion. Rotary motion is what is needed at the drive wheels, belt pulley, and PTO.
The crankshaft is the largest and heaviest shaft in the engine; it is made of alloy steel carefully heat-treated to give the necessary strength, durability and hardness. It is carried in large steel-backed babbit-lined bearings.
The rear of the crankshaft is flanged so that the flywheel can be bolted to it. The front of the crankshaft carries the small crankshaft gear and also a pulley used for driving the fan of the cooling system.
Valves and valve-operating parts. Each cylinder has two valves. One called the intake valve admits fuel mixture; the other, the exhaust valve, permits burned gases to escape.
The camshaft. The camshaft of a four-cylinder engine is supported by three non-adjustable bearings carried in the engine block. It is located above and at one side of the crankshaft. It is made from one solid piece of hardened, heat-treated steel. The raised pieces on the shaft are called cams. The camshaft for a four-cylinder engine has eight cams, one for each valve.