loud tapping after timing belt replacement

I Just got the engine back together after a head gasket\timing belt change. When i started the engine it has a loud tapping noise from the center of the engine (sounds like it is in the vicinity of the fan, but it's hard to tell) I have been DIY for about 2 weekes with a few problems (as shown by my other posts) but nowe i am worried i did something wrong. I had a valve job done, and i have pictures to prove that nmy timing is set at the right marks. New tensioner and pully on the timing belt too. What did i do? I thought i was being very careful and meticulous about the details but now ????

Michael

Did you remember to remove the piston retainer pin on the new tensioner?

I did, but the covers may not be lined up perfectly, tommorow i tear it down again and go through with much patience. On the bright side the engine runs like a dream

Turns out the timing was off by a notch on the passanger side, reset it today and it runs like a dream, now to get the Alt belt tight enough to stop it from waking the dead when i start the car