“PERFECT CIRCLE EXPANDER”

Hawera Star, Volume LIII, 10 March 1934, Page 12

“PERFECT CIRCLE EXPANDER”

NEW LIFE FOR PISTONS. WEARING EFFECT ELIMINATED. One of the foremost American firms specialising in the manufacture of piston rings has introduced a novel device whereby, it is claimed, old and worn pistons may be given a new lease of life—one of greater length, in fact, than is to be expected of a piston in its original form_ The device in question consists of an expander, of rather elaborate design, formed of stout spring steel. It is fitted inside the piston, located by the gudgeon pin passing through it. Necessariiv the piston must be of the splitskirt type, or must have two vertical saw-cuts made in it from a point- just below the rings to the bottom of the skirt, the slits being made at right angles to the axis of the gudgeon pin. Thus fitted, the “perfect circle piston expander,” as it is termed, exerts outward pressure upon the skirt at 10 points. As the slits allow expansion to occur, within limitations determined by the thickness of the piston and the characteristics of the piston material, it is contended that piston slap, oil pumping, and other effects of piston wear are eliminated, and that “new piston performance” is secured regardless of cylinder wear or piston condition.