10-16-2018, 10:21 AM
Have a question going back over 50 years- I had a Rupp kart with a Mac 6 engine. I bought the engine used at a kart shop. The owner said that sometimes these engines fail and the rod's small end needle bearings would try to come out the exhaust port. He showed me the improved piston that didn't have a wrist pin hole on the exhaust side. I didn't think much about this until mine did the same thing he described several months later. My question is- Why would it do this?