http://youtu.be/BaV6rtoeWhk

We've been hearing this for a little while, and since it's inconsistent, it's a bit worrying. Anyone know what this could be?

 

I really could not hear anything, but for starters I would check header gaskets, idler pulleys, collectors, then if you bottom out on the headers it my be a cracked header pipe, then start looking deeper. Like lifters, pushrods, rocker arms.

But just rember Keepit simply.......
You would hate to do a total rebuild chasing a noise to find out it was a broken header."...

 

 

The engine was mostly rebuilt not too long ago, but it does get raced, and hard for long hours. The lifters were not replaced though. The headers have been checked, and the exhaust is new so it's very unlikely that's what it is. The noise is kinda faint, esp with the loud exhaust its hard to hear, but its like :It could maybe be a leaky exhaust gasket, but its weird and inconsistent:
Tap,___Tap,Tap,Tap___Tap___Tap___Tap,Tap,Tap,Tap___Tap___Tap,Tap that kinda thing.

 

I think I may have a similar problem. It is a high pitched tapping, almost like an exhaust leak and really inconsistent. It will be louder if the car is started cold, and the sound becomes more pronounced at idle while in drive or reverse. The sound will kind of drift away when I put it in neutral and give it a little gas, and isn't noticeable while driving down the road. It has all the symptoms of an exhaust leak but the sound is too high pitch, almost like some sort of metal contact. The only time I will hear it while driving is if I give it enough gas to downshift, and then it will sound worse and develop a more haggard sound. Have you had any luck figuring out your issue?

 

To be honest, it was a spark plug wire not connected. So the sound was unburnt fuel doing some weird things. It also explains why we could get flame out the exhaust.....
Sometimes its something so simple.

 

That's good to hear. I figured out what my noise was coming from. Turns out I had a badly cracked flexplate. I was almost positive it was some sort of valvetrain noise, or an exhaust leak. I am actually glad it wasn't my engine, but now I have to pull a flexplate which sucks.

 

i got a mass tapping sound coming from the rear driver side valve cover upon cold startup mellows out as engine warms....lifter,rocker,or push rod. any one know?