I've tightened my header bolts, and checked them for a leak (none). I've had my exhaust checked backwards & forwards, and it looks great.

When I'm idle or revving it in park, everything sounds great. But, when I put it in drive & start going, I hear this tap/tap/tapping. If it were a valve, I'd think it would be present at idle & under load going down the road. Same with an exhaust leak. What do you guys think...flywheel? Does that make sense??

 

Could possibly be the flexplate hitting the starter drive.

 

Sounds like a header gasket leak. Once they start to leak, it erodes the gasket, and you can tighten the blots until you're blue in the face, and it will still leak. The only cure is replacing the gaskets.

Replace the header gaskets. I'll bet you'll find leakage, probably either at one of the places where the bolts are "hard to reach" or between the 2 center ports.

Buy every variety of wrench, socket, or whatever other tool you can find, that fits your hardware; and don't allow yourself to use "hard to reach" as an excuse for not getting them tight at installation. Then re-tighten them ALL after 2 or 3 heat-cool cycles. I have about 4 or 5 different kinds of 7/16" wrenches, every kind of 7/16" socket imaginable from a shallow swivel one to a deep well, in 1/4" and 3/8"; and still have trouble getting to some of them sometimes. Whatever you do, don't accept anything less than fully tightening every single one of them, and re-tightening them as described.

 

I have the exact same thing, I was told it was the flexplate, although i really don't know what about the flexplate, someone here said that it could be it hitting the starter drive, but what does that mean? that the flexplate is loose?

 

I'll consider replacing the gaskets. I was just thinking that I would hear the tapping just by revving it up if it was the headers, though. My noise only comes in with the load.

I just hope I can get enough clearance for the gasket with the Y-Pipe attached...putting headers on was a pain in the butt for me.

 

Well a friend of mine had this tapping problem with his car. Turned out to be one of the carrier bearings worn. Before he found this out, he assumed it was the carrier itself. So he ordered a new one. So guess who gets his old 4th gen posi carrier

 

You said it does it only under load, so in that case it's probably something with the engine, but if it's not the engine, I had a caliper that wasn't working properly and the pad was hitting the rotor (made a tap.tap.tap. sound). Just something to think about.

 

Yea i would think if its engine related, it would be present at all RPM's in all gears. If its only while the vehicle is in motion, that makes me think its either transmission related or it really is speed-dependant and is something in the driveline.

 

Update...yesterday I was poking around, and I heard the mysterious tapping noise with the car in part (just reviing it up). I'm satisfied that it is the header gaskets now.

I shouldn't have to unbolt the collectors to change them out, should I? I was just going to unbolt the header from the head, and pull on it/see. Hopefully I'll have enough clearance & won't mess anything up collector-wise. I'm thinking if I can get it far enough away from the head to spray some gasket dissolver & clean it up with a putty knife, I should be fine. I guess I'll have to let it sit until I'm sure the solvent has evaperated from the pipes before firing up the mill, though .

What do you think? I've seen lots of posts about INSTALLING HEADERS, but I haven't seen the first post about changing the gaskets on headers.

 

Okay...I'm going to answer my own question. I finally found one post that talks of this...here was the reply:

Just loosen the bolts on both ends of the headers and take all the bolts in the middle out. Pull the old Gasket out and make sure you scrape to get out all the scraps. These will come back to hunt you if you don't get them. Anyway, slide the new Mr. Gasket seal in (Mr. Gasket has cut-away holes for the end bolts so they don't require removal), put the bolts back in, tighten everything and your done. If you still get a leak you might have warped flanges, just double the gaskets up. Not sure how hard it is to get around in your engine bay, so it might be aggravating if you have air cond. or anything else in the way. Just try and move everything so that you can get around.

Thanks!

 

For future reference, header leaks and valve taps sounds very similar. However, header leak "taps" get louder the more load you put on the engine. Valve taps are constant regardless of engine load (you can hear them just revving the engine up in the driveway).

 

Another point, for information. Three people have told me this, and it makes sense. When I did the original Header install a few months back, I used standard Mr. Gasket Header Gaskets for a 305. These gaskets have rectangular ports (they form to the head). My HEADERS have circular ports. I should have used header gaskets that fit THE HEADER...circular gasket holes--as the rectangular ones will leak if matched with a set of headers with circular ports (that's where I am now).

Just thought I'd throw this out.