Did a bit of reading earlier, bad ring gaping (too small a gap) can cause the above damage, so can too large a piston to bore tolerance as the piston slop creates a side load on the ring/ring lands cracking and thus breaking them..... and looking at where its broken that could be it....

Cylinder pressure was also mentioned as a possible cause as most force (from combustion pressure) is exerted on the ringland under the first ring, however, knowing how chocolate rst rods are i suspect they would be damaged to???? det was also mentioned but this should be obvious on the piston face too.

High rpm was also mentioned as a possible cause... so essentially every thing lol....

I guess you won't really know for sure... had the engine ever been rebuild?


Any way bugger all this Karl, i reckon your missus dropped it on the floor when you were making the tea

Rob,