i installed a header that has no cat, just a straight pipe and now while im driving i hear a tapping sound. the sound is only heard under light to moderate acceleration. it is rhythmic like a sewing machine and does increase slightly in speed as rpms increase. i have looked around the gaskets and all the welds the best i can and it does not appear to have a leak. i tried listening around the engine at idle with a pipe and had no such luck finding it. Is it possible this is just valve train noise coming through the header since the tubing is thinner than factor and it has no Cat? that is what my mechanic buddy said he though it sounded like. i was just curious what other thought or if anyone else has experienced this.

I have btw read the issue regarding the harmonic balancers in the early models, but my tick is present across a much larger power range than just 3-4k..it can be heard from just after 2k if not earlier all the way up to atleast 5k.

 

My first guess would be exhaust leak, they usually sound exactly like you described and knowing you just added a header.

 

I had a ticking sound like that, it ended up being that one of the bushings in my belt tensioner had come out, so might want to check that too, just in case

 

jcwslayer- if it were an exhaust leak wouldnt it increase in volume as i revved the engine. it is a very constant volume.

 

Not necessarily, you'll notice a leak/noise at lower RPM than higher, if it's a small leak. Exhaust gases will travel past it easier at at higher rpm with little to no noise. If it is it'll eventually blow out and become loud across the board.

Leak at the head due to warped flange. Try using copper gasket with ring seal, 2 stacked oem gaskets or maybe gasket sealer with the current gasket.

If that all checks out, try check the heat shield rattle, if you still have one or if it sitting/contacting anything.

 

ok i just went for a drive here is a video driving with the windows up.. its a little hard to hear what im talking about but the tick sounds goes away at second 6 and comes back at second 11. it the part where its gone is when i take my foot of the gas



this second video is just of me revving the engine and i think you may actually be able to here what im talking about here as well but at a much faster rate which is why i didnt notice it before, there are 2 notes that can be heard, a deep note, and a much higher pitched rasp/ticking note that is the one im refering too. its most noticeable right when i hit the gas in the video.



i also took of the heat shield where the header meets the block and did not see any black soot or anything the exhaust looked dirty but no spots that looked like black exhaust soot.

 

Exhaust leak(check head flange, flex pipe, midpipe connection)
Loose/Rattling resonator internals
Check to see if the midpipe cross hanger is up against the tunnel shield.

 

from the header back is brand new as of yesterday so we can cross that off the list. i will check the connections but i tightened them down pretty good and again the sound was there before the exhaust was put in... the header was installed a few months ago. I think im going to have to get under it while my buddy revvs the engine.. im not 2 excited about being under the car while its running and on jackstands since i dont have much room but i guess i live...Hopefully!

the header bolts are all tight and the flange looks to be nice and flat around the head.

if its actually a leak im gunna have to guess its at the flex pipe because the header to exhaust holes wouldnt line up so i had to unbolt the mid pipe bracket from the car, connect exhaust to header and then bolt the bracket back up so im sure theres a little stress on the flexpipe.

 

i plan on running some seafoam through the pcv valve tomorrow and hopefully if there is actually a leak some smoke will come out for me to find it.

 

Well I'm concluding no exhaust leak after running seafoam through the car, blowing lots of smoke and none coming out anywhere but the tailpipes.

This must be a sound caused by the header or an old sound that I'm just noticing/renoticing after putting new parts in and listening for issues. There is a chance it has something to do with the alta cai because it comes on just as I can hear the air sucking into the intake and it only remains noticeable at partial throttle