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..
The pistons have a cut out on that side at the bottom of the piston skirt. Maybe the metal in the combustion chamber is from the blown glow plugs.
Mark, I am familiar with how the cut out side of a piston looks with no damage.. This finding has come after the engines have stop idling and loss of power..
Piston has dark brown coloring to it. That happens when engine temps get over 300 degree's, the oil blend in the fuel carbonizes and turns dark brownish black...
The piston skirt is the area with the LEAST amount of metal around it, heat it up enough it becomes brittle, then add 20,000- 30,000 + rpms and chunks fly....
Now if you rebuild and you did not service the engine bearings, then your engine may still have debris contaminants in it, so rebuilding just prolongs the inevitable if you do not verify your bearings are in tact..
It's hard to tell by the pics but it sure looks like it was ran hot/lean to me. For a little while anyways...
All Lives Matter
United We Stand, Divided We Fall