My Dart is having trouble burning out the gasket at the exhaust manifold flange. In my case, I have an up-pipe after this, running to a turbo, so there's even more heat and pressure than usual. I am using a flex coupling in that pipe to deal with thermal expansion. What's the best gasket and installation procedure to use to keep this leak free? Some sort of better quality, thicker gasket? Ultra Copper RTV? Cut a groove for an Inconel O-ring?

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Matt Cramer
1966 Dodge Dart turbo / EFI project

Forgot the stock flange dimensions so can’t give exact part but you want remflex…

http://catalog.remflex.com/category_s/103.htm

Thanks! It looks like the 2 1/4" pipe gasket is the one I want for a stock type manifold, for those following. I just wanted to check if anything better had come along, or if there were any tips to make it work even better.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

If either of the two mating flanges is warped, that junction will eat up whatever gaskets you put in—even Remflexes.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I'll check when I have it apart, thanks.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

I have found, in many parts stores, that there are composition gaskets with a stainless fire ring (like a head gasket) that fits the stock exh man outlet. I have had similar problems with my Dutra Dual to Y-pipe setup on my 68 turbo Slant Dart. I tried SCE copper gaskets and they last maybe 2-4k miles at best. Forget about a straight composition gasket. The SS fire ring gaskets last longer than anything else, up to 6-8k miles. I do not have the room/flexibility to try Remflex, but I am not confident they will work as they are very soft. I am sure you can get these SS-ring gaskets online, but I usually just go look at the gaskets hanging on the wall and pick a good one. Once I ordered more online after picking one out.

My pipes/flanges have a slight misalignment too, so even the SS fire ring gaskets don't last forever. Now that engine is out and apart, so I plan to correct the misalignment.

Another thing I will do next time I get into this is to extend the pipe attaching to the exh manifold into the manifold entry slightly. I will carefully bend/grind/fit the pipe so that it fits the exh man opening well and does not restrict flow much.

Happy Slanted boosting!

Lou

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Home of Slant6-powered fun machines

Ordered the Remflex gasket today. If that doesn't work, I may try some sort of inside pipe or other seal.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

I also assume you have everything supported so there is little or no weight on the gasket interface. Asking just in case...

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Home of Slant6-powered fun machines

Clean the surfaces and bolt them together without a gasket… maybe finger tight or a tiny amount more. Take a feeler gauge and go around. It doesn’t take much misalignment to do it

Remflex will take some misalignment as there is some squish… maybe 1/32, but it’s not going to work miracles. It’s the only exhaust gasket I’ll use anymore. They make a manifold-head gasket too. Pricy but worth it.

Correct - the turbo sits on its own bracket so the pipe does not carry very much weight. The idea was to give a lot of room for thermal expansion.

Pierre's idea about the feeler gauge sounds great.

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Matt Cramer
1966 Dodge Dart turbo / EFI project

Feeler gauge idea is a good one. But also look at the flanges and at the failed gaskets. If there's soot across the surface from pipe ID to flange perimeter and/or to bolt hole…y'warped.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Remflex is on. I think a contributing factor to the failure is that I have a flange with slotted holes and there isn't a lot of clearance for a bolt. I had used a bolt without a washer the first time and the slot was wide enough that the bolt seemed torqued down when it wasn't. The extra thickness of the new gasket may have helped when I managed to fixt a washer on the bolt this time. I'll see if that helps.

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Matt Cramer
1966 Dodge Dart turbo / EFI project