Recently I pulled the jugs off my twin BME to see the condition of the internal parts, this engine is about 8 years old, it was flown a lot in Spitfire before the GeeBee Y according to the previous owner ( my friend ) the piston and everything in there were clean like the piston on the video, he was mixing the gas 50:1, I'm running it now @ 30:1 and getting higher rpms because of the added oil.