My buddy blew a 5 port werks the F up last weekend. I think he had a little predetonation going on, but the conrod snapped right across the oil hole for the conrod bushing and it took the piston with it. not a violent blowup so I think the rod had stress cracks from a bad setup. He's a newbie so I have no idea what that motor has been through before, but the piston had a lot of carbon on it like it was in pre detonation. it was quick until it broke though