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Bob Dillon wrote:

bill buttermore wrote: I had one on a Chevy 350 that sounded exactly like a lifter. Would not have believed it if I hadn't heard it myself.

Bill: Do we agree that the noise sounds like it's in the valve train?

My OS (WIN98) will not run flash videos so....???

Andrew, was it ticking before you replaced the plugs?

Yes

Today so far I have replaced the valve covers and put the engine back together 100%.

I took a 4 minute video with my tripod to see if the noise is louder at startup or if it calms down after a while. I haven't looked at that video yet.

I then started searching for the leak. I decided to try to remove the crossover, but in the process sheared the bolts off on the rear manifold, GREAT! Just turned into bigger project. I got the crossover, EGR and rear manifold off.

I noticed hairline cracks in the EGR tubes, both of them, the the mounting ends, under the metal plate fitting. Think this could do it?





Here are the sheared off bolts.


There is a lot of white residue on the insides of the exhaust pipes.



The only spare rear manifold I have laying around is from a w-body so the offset of the exit flange is a little off, but it should work.


I REALLY want to use new exhaust manifold gaskets, they are only $6, but nobody carries them! I'd have to wait until tomorrow to get them. I'm gonna clean up the old one the best as I can and reinstall it, thoughts?

Well I called the dealer and they just so happened to have 1 exhaust manifold gasket in stock, for $10. I got it, since I really only need to replace the rear one.

I also found a different rear manifold off an h-body, so I don't need to use that w-body one.

Now looking at all my spare EGR's (3), they all have the same hairline cracks at the base of the tubes. Obviously I'll use the best one, but is there a way I can fix the crack? JB weld would be too hard once the flange is compressed, and RTV wouldn't hold up to the heat, would it?

i used something called "muffler weld" from autozone that i had laying around, iirc it was like $2.50 or so. its holding up well so far. but, at least on my egr leak, it was more of a whistling than any sort of ticking.

harofreak00 wrote:and RTV wouldn't hold up to the heat, would it?

I don't know exactly what that part of the exhaust gets up to in temp, but as far as RTV goes, there's "copper rtv" that I believe has the best possible heat rating for RTV, cross-reference the two and there would be your answer.

J Wikoff wrote:Does that EGR tube look cracked to anyone else?

Who's got x-ray vision? This guy.

Don't know if that's enough to cause the ticking, because the frequency seemed to slow, but it was cracked none the less.

Well I got it back together. I'm happy to say the exhaust leak is fixed. This was no valvetrain noise at all.

What did I do? New rear exhaust manifold gasket, different EGR tubes (from my parts stash), different crossover donut gasket (from my parts stash). I guess I'll never really know where the leak was coming from, but I do know its fixed!

Here is a before and after video:

Glad to see it fixed!

Did you take it for a drive yet, and does it have any more power now?

Listened to the video three times (thanks for the file, Andrew!) but honestly cannot say whether it is valve train noise or exhaust noise. This comes as no great surprise, as I could never figure out what the tick was in my own L36 . If I had to guess, I would guess exhaust. I hope it is exhaust. If not, it's gonna be a lot harder to fix.

Temperature rating for copper RTV is 700F. Don't know how much cooling occurs between the manifold and the output side of the EGR valve. If you had an infrared thermometer you could shoot it and find out.

Edit for new posts: HOOHAH! good for you.

crash93ssei wrote:Did you take it for a drive yet, and does it have any more power now?

I posted in my project: 40th thread, it drives nice and quite in the lower RPM's, but it just doesn't have any power if you want to move.

I noticed that when I drove it too. It had little WOT power, compared to my car. That was a while ago, already, too.

Yeah, I just read that....

Too bad, it would have been nice if that was the cause of the lost power

Sounds like there's a slight miss now.

J Wikoff wrote:Sounds like there's a slight miss now.

Really? When do you hear it? at idle or revs?

Well I am glad it was exhaust. Nice to hear it quietly purr at idle.

At the beginning of the revs. A slight hesitation/stutter when you crack the throttle.

I get that same hesitation while driving. What could it be? Its got new plugs/wires. Coils tested good. Fuel maybe?

When I've had that problem it was vacuum leaks or wires.

Other possibilities are fuel supply, ICM, dirty MAF... I'm sure you've got spare coils you can try?