Truck has spark and is getting fuel so why won't it start? on 1997 Nissan Pathfinder

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I had to replace a blown head gasket and since I had it all apart replaced the timing belt and water pump, when I took the timing belt off I didn't have the cam locked in place and it turned on me, I thought I had it all lined up as the marks all lined up with the #1 piston at TDC, once I had it all back together it would crank but not the slightest hint of it wanting to start so I set the #1 piston at TDC then removed the distributor cap and noticed that it was way off so I removed the distributor and put it back in with it lined up to the #1 cyl. at this point I tried to start it and it tried to start but as soon as I let go of the key it would die. What could the problem be?
(2) Answers
Remove distributor , replace any bent valves , re-set cam/crank timing , then install distributor , see answer #1 for explanation.....Good luck.