I have recently striped down my TD5 engine to fix the cylinder head gasget. after rebuilding the engine it would not start. The engine turned over on the starter a few times and then the starter motor got jamed. The engine turns over freely on the crank shaft pulley the battery is fully charged and everything has been done properly by the book as far as I am concerned. when I un-jam the starter by the crank pulley and try the starter again it imediately jams again and just clicks away. Does anyone have any ideas ? please help