Red on Red WS6

Ok here is the story. About 3 months ago I did a hotcam and SLP shortie header install. Everything has been great until 3 or 4 weeks ago I noticed a small exhaust leak. Well a week went by before I got under the hood, but when I did the header bolts on the drivers side were sticking out 1/4 inch. So I tightened therm up and double checked the Y pipe bolts, and the leak was still there. Now the leak has got much worse this last week and I have a Knock that is mostly present when the motor is cold. I hear alot of people on this site talking about exhaust leaks causing knock. I am not sure I understand how exhaust could make a knocking sound. I do plan on changing the gaskets this weekend if I can get them shipped here in time.
So I guess my Question is do you guys think the leak is my problem and how can headers leaking cause knock? I am afraid it could be a bearing.
Thanks in advance

neversummer

I also would like to know why an exhaust leak knocks. I could have sworn I had spun a bearing, and perhaps I have. But I just found my exhaust leak on the underside of the manifold. I'm putting on headers soon and am hoping the knock goes away.

Injuneer

Exhaust leaks don't cause knock. They can make a noise that can be confused with ignition knock. That sound, in extreme cases, might fool the knock sensor into indicating "false" knock, and cause the PCM to retard timing unnecessarily.

Z06Z28

I think the word "knock" to describe the sound you are hearing may confuse a few people. I think the word "ticking" is what you might wanna say. ...so your hear an exhaust leak tick sound? A faint tick tick tick...looks like its time to re-do those gaskets and get those puppies tighetened. I did have a ticking sound with my LT1 and I was afraid I messed something up. After guessing around, I found out that my flange gasket had a leak at the flange. I dunno about you but for me the flanges are kinda difficult to line up and bolt up snug if you didnt tighten each side a lil bit at a time. The exhaust leak will make that ticking sound, we hate it..most of the time..once it leaks..no matter what you do..it will still leak so your ganna have to pop that header off and doctor it up. Next time keep a watch out for the bolts on your header that back out. What I do as a weekly check up...cuz I have a black cloud over me ..every friday I take a visual of all my hoses, wires, header bolts and also check to see if my E-cutout is still attached..dont wanna loose that..

calfirebird

No, What he is saying is it sounds like a Knock!! Not a tick by any means. It more sounds like a worn bearing tapping aginst the cam at first startup, and then fades away after about a min. Then the exhaust starts to sound like a normal exhaust leak. I didnt think to much about it untill i heard it start up and it was like WTF I helped with the cam and i damn sure hope it isnt the motor for i dont want to pull an LT1.
Thanks guys

neversummer

Ticking is a good word to desribe it. I've known for a while that I had a small exhaust leak - (real quiet ticking). But then one day, overnight really, the ticking became much louder - so I thought it was rod knock. But I just found the exhaust leak - pretty good size hole. Then again, it still could be rod knock AND I have an exhaust leak!