I received one of the first kits that were advertised on this site.The first time I ran it I noticed bearing slop in the case as soon as it warmed up and after cooling down it would tighten back up. I removed .002 off the bottom cover and that resolved the problem. The aluminum case expanded more then the bearing after warming up causing the problem. It is probably just a very few engines that have the bearing saddle machined too loose. The engine was NOT overheating! I have over 30 flights on it now and it is a good engine! Hamman