I know that most everyone flies turbines (I will soon also) but I still have a D/F plane and I was taking apart an engine yesterday that had the JMP tuned pipe on it with the big fat orange silicone seal. When I took the head off it looked sand blasted, like little while spots (thousands of them) on the head and the top of the piston. I have heard that this can be a problem if the critical length of the tuned pipe is too short, but this tuned pipe was made for this motor and there is no way to lengthen it. Just curious to know if anyone has had this problem or knows how to fix it. I'll attach a few pics, but the didn't come out all that great. Thanks, Mike L