smacota1

I keep having the gasket burn out on the heat riser spacer. After I replace the gasket it will last about 2 months. This week I changed another burned out gasket but this time I have used a fel pro gasket instead gaskets I bought from one of the corvette specialty houses. Never had a problem like this with other older cars I have owned.

Not a big deal but would like to know what are some thoughts would be about the issue.
1. Flange is clean and not warped
2. Heat Riser is an adapter , no valve mechanism

phil2302

You can skip the gasket like I have done and just use a hi temp RTV sealant like Permatex makes.
I use it for exhaust maniolds also no gaskets.

SJW

Sure looks as though something's not flat. I think I'd try stacking two or three gaskets in there.

Live well,

SJW

smacota1

That sounds like a good suggestion. If the fel pro gasket does not hold up I will give that a try.

Thanks

smacota1

Might try that as well.

Double checked the adapter and it was flat. Could be the manifold instead.

Thanks for responding.

67:72

The blown gasket is the upper one between the riser and exhaust manifold, right? The lower gasket between the riser and the pipe is a doughnut gasket. If it's the upper connection you are having issues with, it seems the mating surfaces are not fully seating against each other. Run a file across the bottom of the manifold to see where surface imperfections may be. Keep two points of contact across the opening as you do this.

Upon assembly, perhaps loosen the mid-chassis connection to allow the down pipe and riser to move a bit to seat against the bottom of the manifold as you snug the nuts. Also try wiggling the pipe as you tighten the nuts to also help the surfaces find each other.

smacota1

Yes sir, the upper gasket. Great suggestion. I will try this the next time I have to change the gasket. Hopefullythe fel pro will be better.

Thank you.

skids

I agree. The down pipe needs to be able move/be loose so the nuts will draw up the flange evenly and completely.

smacota1

Thanks all. I will circle back in a few months and let you know how the fel pro gasket worked out.

DansYellow66

My sidepipe car has seemed to be getting louder and even harsher and I started wondering if I might be developing a manifold to pipe leak. It’s a pretty rowdy motor. I doubt it’s the donuts as I have the steel pipe inserts and the Allen’s sidepipes, while getting close to 30 years old, don’t have enough use to start rusting out. But now you’ve got me to thinking about the heat riser spacer gasket failing like yours, so I’m going to check mine out.

smacota1

OK, I said I would circle back with an update if the Felpro gasket solved my burn through issue. I installed the new fel pro gasket #9097 in June and so far the nuts have not loosed nor has there been a burn through like the other gasket #322126 I had been using.

Hope this helps anyone else with the same problem.

md m

I use a bead of high heat red RTV on the gasket. Many years, no leaks