I've had the same problem with three different traxxas nitro engines.. The pro15 2.5 and 2.5r where the bottom half of the piston skirt on the intake side is breaking off and I'm finding metal shavings on the top half of the engine after it starts blowing glow plugs.. Probably not gotten 3 - 4 gallons of fuel through any of these engines.. I'm not a racer or basher I run these engines on pavement.. Im using Byron's 20% nitro and the lubrication is 12%. Engine temps have averaged 200 - 230.. Is this the nature of the beast or am I doing something wrong with these traxxas engines? Im very frustrated and cant keep throwing money away like this..