Scuffing, Sticking, Breaking of Piston Rings

Scuffing, Sticking, Breaking of Piston Rings Points : Scuffing, Sticking, Breaking of Piston Rings, problems in internal combustion engines, ic, engine The principal requirement of a piston ring is that when compressed the fuel into the cylinder, it shall bear evenly all round, and shall not have too large a gap.

In order to prevent the escape of gases past the rings it is necessary to arrange for the latte to exert a certain radial pressure outwards against the cylinder walls. This pressure must only be sufficient for the purpose during the normal working conditions for excessive pressures reduce engine power and also give rise to greater cylinder wear. Modern piston rings are of the narrow axial thickness type, of good quality alloy cast iron having elasticity properties, or flexibility so that they can readily be sprung over the piston without breakage or permanent set.

The rings are now always supplied by specialist piston ring firms and are of a high standard. The type preferred is the diagonal-cut, one with uniform or graduated radial pressure produced by preening followed by peripheral grinding with the ends clamped together. It has been shown that if the correct ring gap measurement is given there is no more tendencies for gas leakage past this kind of joint than the step-cut or any other one.