Stripping an engine to put a new piston in is a fairly significant amount of work for the amateur - not too difficult, but you have to know what you're doing !
So given the state of this piston, either someone didn't read the manual properly and then couldn't be bothered to investigate the rattle that must have been deafening on initial startup! Or alternatively, there's a rogue mechanic in a repair shop out there somewhere that doesn't know which way round to put pistons - surely that can't be true
