My timing chain broke and distroyed all the gears,and broke the cam shaft and 1 cam bearing. I sent the head out and had 4 valves replaced after I saw the pistons were o.k. Got it all together set #1 at TDC and aligned the cam shaft groove with the mark on the gear; pulled the pump out and set the timing at 25 degree BTDC. To my surprise as soon as I had the air out of the fuel lines at 10 degrees temperature it started right up. Problem it ran 1 minute and quit. Thinking there was some air in the lines I tried to start it twice more. It ran for a few seconds. Then on the 3rd try I heard noise. Valve cover was cracked. Took it off and the cam shaft was broke again and 2cam bearing. Valves were set intake .004 and exhaust .016. Setting the timing and valves I rolled that engine over at least 25 times with a socket on the flywheel and there was nothing holding it. Any ideas what I did wrong.