So I tried running the B6 in my first ever nitro qual. Broke my buggy on the first round of qual, had no issues the 2nd round, and on the 3rd round couldn't get the engine to start. After all the frustrations I decided I was going to convert the buggy to electric. After removing the engine, I noticed a gouge on the piston through the exhaust port. I removed the piston and sleeve to see if I could figure out what happens. Turns out the clip that holds the piston on the wrist pin came out and the engine ate it. Has anyone else experienced this?

I never ran this motor on my own. Only at the track with experienced nitro guys. Other than having issues getting the engine started the first few times, it ran fine for break in and up to the point it failed. It had less than a gallon through it.