Just add one more thing, wasn't the first physical evidence that there were brass type filings in your oil ? These cannot possibly come from pistons.
Most professional people won't say any more than they have to when commenting on other's work. This is because it is not always clear to them who did what and who put what together. They usually will send work to each other if they don't have the right machine, etc. so making enemies in the industry is usally not something they strive to do.
