nice set up i like the scratches on the chassie

shuttlex if the engine is brand new and hasnt been broken in yet im going to guess that it got stuck because the tolerences arnt meshed yet, the piston and sleeve have not ground themselvs down (so to speak) so they fit together nicly, at tdc there is the most amount of contact between them and this is why it got stuck there, again this is just me guessing, it doesnt sound like its too much to worry about unless it starts doing it after the engine is broken in.