Can't get good seal at flange between manifold and exhaust pipe

[Rustbuster78]

From the looks of it, no gasket is required. It looks like the piece at the flange is supposed to fit the bevel in the manifold outlet, but no matter what I do I can't get it to seal. Do I slop it up with muffler cement, or is there a better option? Edit- Forgot to say this is on my 1978 HL510 goon.

 

Edited August 1 by Rustbuster78

[thisismatt]

Why wouldn't there be a gasket?

[thisismatt]

https://www.rockauto.com/en/catalog/nissan,1978,510,2.0l+l4,1210004,exhaust+&+emission,pipe+flange+gasket+/+seal,5836

[Rustbuster78]

5 minutes ago, thisismatt said:

https://www.rockauto.com/en/catalog/nissan,1978,510,2.0l+l4,1210004,exhaust+&+emission,pipe+flange+gasket+/+seal,5836

None of those are right. It has three bolts.

 

[Rustbuster78]

I really can't find any photos online of a manifold like mine. Another issue is that the gasket would have to be really thick to fill the gap as the tapered flange piece sticks out quite a ways. I can try to take a picture tomorrow because I feel like I'm not explaining things very well.

 

Edited August 2 by Rustbuster78

[datzenmike]

Yes. Somewhat like a valve and valve seat but a rounded surface so it doesn't need perfect alignment. It's more like a ball and socket fitting. 

 

Make sure the two surfaces are undamaged and clean. I don't think there was a gasket for this.

[thisismatt]

Ah, okay, yeah I've seen that type as well

[Rustbuster78]

1 minute ago, datzenmike said:

Yes. Somewhat like a valve and valve seat but a rounded surface so it doesn't need perfect alignment. It's more like a ball and socket fitting. 

 

Make sure the two surfaces are undamaged and clean. I don't think there was a gasket for this.

Yes! That's right. And I finally found a photo of one online. http://datsun1200.com/uploads/photos/22644.jpg I

[datzenmike]

Here's another

 

[Rustbuster78]

8 minutes ago, datzenmike said:

Yes. Somewhat like a valve and valve seat but a rounded surface so it doesn't need perfect alignment. It's more like a ball and socket fitting. 

 

Make sure the two surfaces are undamaged and clean. I don't think there was a gasket for this.

I did try cleaning both surfaces with a wire brush, if there is any damage then it must have been caused by me as it was good before I took the manifold off the replace the intake/exhaust manifold gasket after trying to repair a crack in the intake manifold which didn't go so well either. I tried using one of the aluminum brazing rods and it cracked again after trying to reinstall the pcv valve so I gobbed rtv over it for the time being.

 

[datzenmike]

The seal was further helped along by rust and exhaust deposits. Once you broke that bond it's harder to seal again. Try some of that muffler cement.

[Stoffregen Motorsports]

High temp Orange RTV works well, but looks like crap.

 

You could also glob on some Anti-seize. It will sort of cake into place. Don't breathe the fumes though...

[Fat510]

A muffler shop could probably make you new flange but replace the manifold first. Or you could swap for the gasket type manifold with the matching flange and have it welded on to your exhast