The piston ring compressor is a special tool that is specifically designed for compressing the piston rings when a piston is re-installed. This is accomplished by opening the piston ring compressor enough so that the piston will slide into the opening. Then the rings compress by tightening the tool so that it is snug around the piston. The piston ring compressor can be tightened by turning the adjustment arm clockwise, and loosened by turning the adjustment arm counter-clockwise while holding the release spring down as shown below. It is important to lubricate the piston ring compressor as well as the cylinder bore with oil before attempting to push the piston down into the cylinder.
