HI, I have a chance to get one of my engines rebuilt for next to nothing by the local Technical Colledge (not too sure what you call it in the US) I have a pair of 115 Fichts with lots of hours on them, but still going like a dream, should I get it done and risk a dud rebuild, even though the students are being trained by qualified teachers, or should I just keep the engines as is till something "dies"