Exhaust leak at pipe to manifold connection

[Cuda416]

When we made the down pipes from the manifolds to the rest of the system, we used these to connect to the manifolds. We seem to be having a leak on the passenger side that may be coming from this connection. Need to check for the exact spot but I'm pretty sure this is the culprit. They are connecting to factory 273 manifolds on a 65 Valiant. I looked at the "doughnut" style gaskets but they seem to want straight walls on the manifold side instead of the curved ones on the 273's. At this point I'm thinking we should have used the flat style but this is what we have no and no time in the short term to redo it. What's a good way to seal it up until then?

 

[Treblig]

That looks like the correct down pipe. One thing I've found when installing this type of down pipe is that you have to install that section first (the one pictured). Make sure it's centered and aligned concentric so that you get a complete seal. If it's cocked to one side it might leak. I install the section in the pic then tighten it making sure it doesn't rotate or move. Once it's locked in place I install the rest of the exhaust piping making sure there's no side stress on the connection. Once it's locked down and properly installed it should stay good for a long time. I used to make these when I made the 340 down pipes, one thing I used to do is put a manifold in a vice, put the pipe against the cone of the manifold then using a hammer I would hammer the cone part of the pipe against the cone part of the manifold, rotating it as I go to shape the pipe cone to match the manifold cone. I'm sure you don't want to remove your manifold but but I'm just telling you what I did to ensure a good seal.

 

[Cuda416]

That looks like the correct down pipe. One thing I've found when installing this type of down pipe is that you have to install that section first (the one pictured). Make sure it's centered and aligned concentric so that you get a complete seal. If it's cocked to one side it might leak. I install the section in the pic then tighten it making sure it doesn't rotate or move. Once it's locked in place I install the rest of the exhaust piping making sure there's no side stress on the connection. Once it's locked down and properly installed it should stay good for a long time. I used to make these when I made the 340 down pipes, one thing I used to do is put a manifold in a vice, put the pipe against the cone of the manifold then using a hammer I would hammer the cone part of the pipe against the cone part of the manifold, rotating it as I go to shape the pipe cone to match the manifold cone. I'm sure you don't want to remove your manifold but but I'm just telling you what I did to ensure a good seal.

Thanks man, I'm not gonne be able to do any of that since we welded it to the downpipe section (2 feet-ish). Thanks for the tips though.

Any good way to seal it as is until I can do it better?

 

[Treblig]

Thanks man, I'm not gonne be able to do any of that since we welded it to the downpipe section (2 feet-ish). Thanks for the tips though.

Any good way to seal it as is until I can do it better?

Not without cutting it free and realigning it? Maybe someone else will chime in. But you can get under there and look to see if the bell flange of the down pipe is aligned with the bell on the manifold (not cocked)....if it is properly aligned you might try spray lube on threads, loosen connection, break loose then retighten. If you loosen it and it pops off and it's crocked you'll have to refer back to my original post!!

 

[Cuda416]

Not without cutting it free and realigning it? Maybe someone else will chime in. But you can get under there and look to see if the bell flange of the down pipe is aligned with the bell on the manifold (not cocked)....if it is properly aligned you might try spray lube on threads, loosen connection, break loose then retighten. If you loosen it and it pops off and it's crocked you'll have to refer back to my original post!!

Roger that. Thanks again.

-C