RE: worst engine ever
My worst engine was a ASP52. It would run like a demon on the ground but would cut out after about 4 minutes in the air. Tried everything, replaced the piston and sleeve. Only After I replaced the bearings it seemed to have been ok but I sold it the first chance I got. A year or so later the chap I sold it to came flying at our club with it in a Spitfire. It did the same thing, would run well for a while and then just cut out. Everyone helped and gave advice but nothing helped, I stayed well clear of it!