Exhaust doughnuts

[anwat]

Noticed I had an exhaust leak where the headers connect to the collector. Tried tightening the bolts down, didn't help much. So, I took it apart thinking the doughnut may be cracked. Come to find there is no doughnut, no gasket, nothing at all between the two pipes. Am I missing something, or is this the way it should be? There's no bits or pieces of anything in there, making me think maybe there never was anything.

If there not supposed to be anything in there, how am I supposed to stop the leak?

 

[Bent77]

That is a ball and socket style joint. Anything will leak if it wiggles enough

Surprisingly, black permatex works well s long as it’s not trying to bridge a hole

 

[Fastereddie]

That is a ball and socket style joint. Anything will leak if it wiggles enough

Surprisingly, black permatex works well s long as it’s not trying to bridge a hole

Also maybe scotchbrite the mating surfaces to smooth any of that surface rust. The smoother it is, the better the seal.

 

[anwat]

Thanks for the info...I'll clean it up and use the permatex and see what happens. I can see part of the leak is from a hole burned through when the bung was welded in (you can see the big buildup of metal between the flange and the bungholio, that's where it burned through) , that may be where the majority of the outside air is coming from. The other side barely leaks at all, just a couple of bubbles from the joint.

Will that permatex make it next to impossible to get the joint apart next time? And it's OK to use that close to the O2 sensor? And I'm guessing that to switch to a different joint, I'd have to get new headers, correct?

 

[Bent77]

1) It will make it stay together, say like an intake. You won’t have to cut it

2) permatex is ok next to the joint. Once it cures, it works no different than it applied in another application. You just don’t want it on the sensor

3) if you want a new adapter, you need a welder. The ball and socket is one of the better exhaust unions. I prefer V bands

 

[anwat]

I was just reading up on the V-bands. Next time...these headers haven't leaked at the block yet, so I don't want to touch them...Plus I'm not sure how easy it would be to weld to the header, it's got some ceramic coating that would have to be removed.

On the Permatex: There's ultra black gasket maker and then black adhesive silicone sealant. Those say to 500*F...then there's permatex muffler and tailpipe sealer that says it's good to 2000*. Which one?

 

[nvrenuf]

Ultra Black looks like the only one that specifies “sensor safe”.

 

[Bent77]

I’ve use all of the above, but the Ultra is the safest bet

 

[Wes Harden]

I used GMS (General Motors Silicone) on all my stock air cooled VW J pipes, where they slip together. The GMS was clear.

 

[dyeager535]

GM used springs on the bolts joining exhaust to the manifolds. I bought a set, I'm going to try those springs with the ball and socket header setups.

You really don't want to overtighten those ball and socket joints, they start to deform.

Making sure your exhaust is solidly mounted downstream of the collector is important. If you can easily move the pipe at the outlet, that's all leverage on your collector joint.

 

[beags86]

Another thing to think about is adding a flexible pipe section after the head pipe.
Granted it's a expensive solution if you can't do it yourself.
But it will ensure your engine and headers can flex separately from the exhaust system

I won't build a exhaust setup without these anymore.

 

[83ChevyK5Blazer]

^^ what beags said, my old truck used to eat collector gaskets before I added a couple flex pieces to the pipes.

 

[anwat]

Thanks for all the tips. I smoothed it out, used the black ultra, tightened it all down and guess what...no leaks whatsoever. Now, I could see that most of the air was coming from where the bung had been welded into the pipe. There were holes in the weld bead and air was coming out from all over the flange side. I tried to reweld it and while i got a lot of it sealed up, I couldn't get to the frame side without taking the whole pipe off again. So, I slathered some of the black sealant on there, and it's not leaking anymore. For $23, I got another Heddman ball joint with the bung already welded in it and when it comes, I'm going to replace the whole section and put a piece of the flex pipe in where it joins up to the rest of the pipe using the V joints. That should take care of it for a while, and I can get it apart if I need to for some reason.