sounds to me like you got some dirt in the engine somehow and it polished the piston till it finally wore the sleeve happened to me awhile back. if the engine is just out of pinch you could buy a new piston/sleeve/rod combo kit from amainhobbies for 169.00 and mabey a new bearing if needed and just rebuild it. when my p-5 blew up i just replaced the piston/sleeve/rod with a 7 port conversion kit for it and it screamed. but some people dont think a mill is worth rebuilding for near 200.00 on high end engines when you can get a new one for around 300.00. but if you just whant a new mill check out radical engines at amainhobbies thease mills are super fast and run all day at 195-200 deg. and they are under 300.00 or axe motorrossi just came out with the cobra its alittle over 300.00 but i heard they are screamers to. hey did that long wheelbase chassis take away any steering? i have a used ttr on the way from ebay and i have a standard wheel base flat chassis for it plus about 400.00 in red goodies just sitting around