I've had this noise a couple of times and both times I dumped in some fuel injector cleaner and the noise disappeared.

 

Cam gears are torqued properly, no metal flakes. I am really starting to wonder if the noise isn't piston slap.

 

Finally got a video of this. Let me know what you all think. I will be tearing into this again and hopefully have a answer soon!
http://www.streetfire.net/video/evo-tapping_2389802.htm

 

well going to pull the head and tear it down thinking I might have a bad valve guide or broke spring.

 

What was your piston to wall clearance?
Has the block been decked? If so how much?
Has the head been re-surfaced? If so how much?
Lastly if you answered yes to the two questions above what thickness headgasket did you use?

Sounds like the pistons are hitting the cylinder head.

 

Thats not a bad valve guide and I doubt a broke spring...Are you SURE its not an exhaust leak at one of the ports? (since the sound is the sound of one cylinder firing)...I've heard a few exhaust leaks that literally sound just like a tap or knock (one was driving me crazy on my mustang and was a header gasket)

If it's still together...Heres what you do...While idling disconnect one injector (can only do spark on 2 of the factory ign setup unless u have a cop setup) at a time and see which cylinder makes the sound change most differently. That will tell you which cylinder it is....

If it was piston to wall clearance it would do it on ALL the pistons not just one like it is doing, (if they were all the same anyway). I was hunting down a similiar noise for months and found out it was the wristpin bushing in my manley rod. I found out which cylinder by doing the method above. I found out it was the problem by taking out all the plugs...turning engine over until the piston is like halfway on the downstroke (by using a long screwdriver on top of the piston) of whichever cylinder your checking and then pushing down on the screwdriver and if it clunks or moves down or does somethign than the other cylinders than its the wristpin bushing or rod bearing...Try it!

And just because its a fresh motor doesnt mean it cant be a bearing or something...Who machined and built it?

 

I am not sure of the PTW clearance and the block was decked once. Using a stock head gasket. I just got the head off so we are going to tear it all the way down make sure everything is good and I will check the wristpin/bearings like you say...will be a lot easier with the head off now. We had to tear it down once already and had an ovaled wristpin. Hopefully that is not what it is again. The cylinder walls piston tops and bottom of head all look fine doesn't look as though anything was smacking or slapping around. As for an exhaust leak after checking out the gasket it doesn't look like it was leaking at all.

 

I just disassembled mine and mine was as of now piston slap,i removed the pistons and measured clearances and my PTW was 0.0095" way too much for coated pistons specially when Manley recommends 0.0035",i should have my block back this week and should have it running by the weekend,hopefully with no noise

 

let me know it that takes care of the problem I have my head off now working to get it all apart and inspect all the valves, guides, and springs.

 

Will do

 

I will make sure and keep everyone updated on my situation as well. I always try and make sure to post the solutions when I find them so when people search the forum and find a problem relating to theirs they actually find the answer in the thread instead of coming across a "cold lead" lol

 

UPDATE: well it seems as though I have exchanged one noise for another. This noise was due to a couple of bent valves and some bad guides. I have had the valve job redone with new valves. Fired it up now i have a tap every now and then no rhythm to it and it is not too bad so we are definitely improving haha