Misc. Exhaust to Manifold Seal

[huntnCJfool]

Is there any special trick to getting the exhaust mounted to the flange? I have a 79 with the spacer gasket. I have tightened down several times using the gasket from my engine swap and can't get rid of a tiny leak I can feel. There previously had not been a leak before the swap. I've got a new gasket to pick up tomorrow but just figured I'd ask if there before I tried again.

 

[CJ]

N

Is there any special trick to getting the exhaust mounted to the flange? I have a 79 with the spacer gasket. I have tightened down several times using the gasket from my engine swap and can't get rid of a tiny leak I can feel. There previously had not been a leak before the swap. I've got a new gasket to pick up tomorrow but just figured I'd ask if there before I tried again.

Not sure what you mean by a "spacer gasket." Is this an xtra thick gasket? Do you have a straight edge? Need to check flatness of the mounting surfaces, both primary mating and secondary receiving.

 

[huntnCJfool]

I checked the surfaces with a straight edge before re assembly they are good. The gasket I have seen called a composition donut elsewhere, it is kind of a fiber wrap impregnated with a metallic something.
My old one looks kind of rough but as I said it did not leak. I did notice the exhaust hanger near the transmission kind of pulls the exhaust towards the drivers fender when no attached to manifold so maybe I'll try unhooked that. Just desperately trying not to break a stud, I know I should only need around 20 lbs of trq. He'll if I can't get it I may just take it to an muffler shop. All the work I have done I'd rather pay 50 bucks than snap a stud....

 

[Manic Mechanic]

slap it together with no gasket. ive had quite a few that leaked with the donut and not leak with no gasket

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[huntnCJfool]

I did think about that, it definitely won't hurt to try. It does seem like a bizarre thing, essentially making one potential leak source into two with such a wide gasket.

 

[huntnCJfool]

Quick update, I cannot hook up with no gasket. The gap and angle are both too big to fill. I picked up my new gasket this morning and it seems to be much better, with alignment tabs for the manifold and a material that will likely seal up nicely with some heat cool cycles and tightening.

Here is a side by side comparison. The old one is just a metal piece that extends into the exhaust with some brittle fiber. Not sure if it's original or if the muffler shop put it on a few years ago when the exhaust was replaced. Either way, I will post an update once I am driving as the new ones seems like another good product from FelPro

 

[Manic Mechanic]

seams to me ur muffler shop screwed up. the flanges should fit flush with little to no gaps

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[huntnCJfool]

seams to me ur muffler shop screwed up. the flanges should fit flush with little to no gaps

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Considering the exhaust has run in this exact configuration for 3 years with no leaks, and all I did was swap 258's, I would not go talking down on a ship. The shop actually was old school and gave me a fantastic deal. Smh

You do realize there are 2 different configurations. When they separated manifolds they got rid of the donut.

 

[RiverandSand]

The new gasket slides over the adapter piece in your picture, discard the old gasket

 

[Manic Mechanic]

here's two different 258s one with a brand new exhaust other factory original. even if the shop gave a great deal. doesn't mean they weren't slightly off on their bends.

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[huntnCJfool]

here's two different 258s one with a brand new exhaust other factory original. even if the shop gave a great deal. doesn't mean they weren't slightly off on their bends.

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Those both look like the post-80 manifold that have the flange on the manifold.
Here is an 83 manifold, with the flange attached:
View attachment 74325

Here is the manifold from my 1979, it is flat on the base with just a hole. Sorry I don't have a picture of it without the exhuast mounted:

View attachment 74324

Luckily the point is now moot, the new gasket has sealed the leak. I appreciate the tips! The new gasket really is seems like a much better piece than what was in there and was three bucks well spent.

 

[Manic Mechanic]

anytime something fixes a problem its money well spent.

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