K Series pistons page

This page shows what happens to the standard K pistons when they are subjected to higher RPM and BHP, these are form Tor Atles Caterham Superlite 1.6, producing between 190-200BHP, rev limited at 8000RPM. The ring land between the top and second ring has become completely detached , the next stage of disintegration is shown below, the top land breaks away exposing the ring and pressurising the crankcase. The damage is always sustained on the inlet side of the piston where the thermal shock is highest, this side of the piston is cooled by the incoming charge, then heated by combustion. Further below are some pictures of the Omega forged replacement piston.



This damage then progresses up through the top of the piston as shown below.

And here is the forged replacement from Omega, the ring lands still do not look very substantial, but at least the material is much tougher, they sit around 1mm higher in the bore and raise the CR by around 1 ratio, they also have large recesses to clear the valves.