It happened again. My first flight lasted 3 minutes when the engine quit. After landing i noticed that the damper in YS mount had broken and further inspection found that the conrod had sheared. I replaced the conrod and restarted the engine, she ran well for a minute and then again the conrod failed. This time it didn't break apart but seems to have elongated around the crankpin. My fuel is 10% Klotz oil and 20% nitro. Can't quite figure it out. This time when I opened the back plate the engine parts seemed to be well lubricated. Due to the elongation of the con rod, it had scored the crank case in some areas. I now feel a certain roughness from the bearings as well. Quite a mess. I have cleaned all the parts and plan to get new bearings and also con rod to give it another go. Could there be something else that I need to look into? The crank pin looks smooth and doesn't seem bent.
Your thoughts please?
Thanks