Figure 3-21.Wick seals.
Pistons (fig. 3-22) are usually made of an aluminum
alloy. They are a sliding fit in the cylinders. This serves
several purposes as follows:
Transmits the force of combustion to the
crankshaft through the connecting rod.
Acts as a guide for the upper end of the
Serves as a carrier for the piston rings that are
used to seal the compression in the cylinder.
The piston must withstand incredible punishment
under temperature extremes. The following are