I know this might sound daft, but are all your plugs in ? Have the tappets been adjusted perhaps a little on the tight side ? For the engine to whizz over it sounds like a loss of compression somewhere, if there is no physical damage visible then you got to be thinking valves or valve train or a holed piston but that all sounds very dramatic for just having your engine in and out, didn`t fall off the trolley jack or something silly like that ?
Ozziedog,,,,,,,,,,,,,,, Let`s hope for something simple maybe :mrgreen: