Exhaust flange and gasket problems.

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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

BadDog wrote: Mon Feb 18, 2019 1:21 pm Not familiar with that stuff. Good to know, thanks. Do you think that a full surface gasket of that stuff would be better than the narrow width remaining of the steel/fiber resulting from the 9/32 over size diameter hole in the gasket I modified to fit? Call it roughly 1/8" wide where about 1/4" wide sealing width would be possible with a (just over) 2" ID hole in the gasket material in question? Not sure how much the steel inner will offset the loss of sealing width...
Most exhaust flange gaskets, including header collector gaskets etc, are full surface flange. I would think that would be better than just a ring, as it would be more difficult for the exhaust to find a path out somewhere through the gasket.
Most I've made, I cut the exhaust hole with an Exacto knife, and did the bolt holes with a hole punch. For the outside, I just use the ol' ballpeen hammer trick.
I snug fit on that pipe would make it more user friendly to assemble. The gasket won't fall off and go into the black hole somewhere. ;)
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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

The stuff with the steel cuts pretty well with a good pair of snips. It's not that bad to work with, and, it can be cleaned up with a die grinder.

Those hollow punches work on it too, for the bolt holes. have also used one to cutout the center hole, taking 47 shots at it to get there...
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BadDog
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Re: Exhaust flange and gasket problems.

Post by BadDog »

Agreed. And full flange supports the ears equally, thus reducing warp otherwise induced due to clamping over air.

The gasket hole punch was my plan on modifying the steel cored 31305, but that didn't work so well for offsetting the holes. The (stainless I assume?) steel core just deformed, and I was worried that continuing to beat on it would require repairing the hole punch edge. So I finished it with a fine die grinder burr.
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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

I think full flange is the way to go....and I didn't even think of the warping from the bolts. Another good reason.
I've made my own punches, and half punches. Work great on just paper, but the steel, which all I have seen has been stainless of some type, is tough on 'em.
Still can get it done, but takes several regrinds on the tool.
The burr, with patience, and good work holding, works great!
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BadDog
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Re: Exhaust flange and gasket problems.

Post by BadDog »

For the die grinder burr work, I took 2 pieces of random "may need it someday"s with the right size hole, and clamped the gasket in between them in the vise. Used the holes somewhat like file buttons, pretty quick and painless, and much less work than fixing the punches that were still nicely sharp.
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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

Good plan!
I've done the same, sometimes with plywood or pieces of paneling.
Also one of the reasons I've carved my own punches out of pipe, or steel tube. Easier on the ol' wallet to buy a 1/4" or 3/8" pipe nipp than a new punch!

If you haven't dealt with Summit, and go that route, I've used them for years, and they have been excellent.
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BadDog
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Re: Exhaust flange and gasket problems.

Post by BadDog »

Yeah, used Summit for years. Great when you can hit the free shipping, otherwise usually better sourced locally if possible.

In fact, I got most of the bits I needed to cobble together this turbo from them, including the mandrel bends, braided turbo oil feed line and AN fittings, etc. Free shipping! And thicker gage mandrel bends than I could find locally (3 x 2" 16 ga "U"s - Summit brand) without paying silly money.
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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

Been quite a while since I paid for freight from Summit. Maybe I'm just lucky. They seem to be a lot like Enco, and run a lot of specials. Their pricing is usually better than most too....and they have a lot of good stuff!
Nice thing here, if I order early enough, I get it the next day. The store & warehouse is in Sparks, so only 160 miles from here.
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BadDog
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Re: Exhaust flange and gasket problems.

Post by BadDog »

I think I know more of what's going on, and why there seems to be no gasket.

When I was looking at the flanges I found while trying to figure out what industry might provide a gasket, on one of the clearer images, it appeared to be beveled in the ID. That made me wonder if maybe it wasn't actually a gasket flange, but rather a flare end donut flange. While talking to a friend last night about that evolving thought, it occurred to me that the donut flange on the other end is about the same size. Not sure why I didn't make that connection before...

So I looked at the other end and, sure enough, it's exactly the same flange as the stock flare and donut use! Not close, EXACTLY.

The bevel wasn't apparent on my "flange" because they just flipped it over and used the bevel as a weld groove. When I cut it off and turned/ground it flat, obviously the bevel no longer existed. Not having been produced originally for a flat gasket seal might explain why the surface wasn't even, and might explain why it seems those "not meant for that flange" gaskets don't hold up.

That also explains why I had such a horribly loose fit to the new pipes when I rewelded it onto my new cross over. It was a bit of a pain to weld, but just what you need for a slip fit donut flange. But in any case, the core-hole in the manifold casting I have does not lend itself to switching to a donut on that end. I really wish it did.

That makes me wonder if maybe they originally tried to put a donut at both ends, but found it unstable or something? Or if they were just punching up their margins by using a cheap donut flange that they are now buying in twice the bulk. My opinion of Banks just keeps dropping and dropping...
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warmstrong1955
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Re: Exhaust flange and gasket problems.

Post by warmstrong1955 »

Is that all something that Banks did?
If so, I agree....they have some quality problems.

Regardless, nothing wrong with a flat gasket anyway. The ring gaskets (donuts) are more forgiving when you have a slight misalignment, but that's about it. They often tend to compress over time, and leak, depending on the style and construction.
The old 714 Deutz engines used big woven donuts, a short tube with tapered flanges on both ends, which two bolt clamps. It was for a slip joint connection from the manifolds to the rest of the exhaust system. Even with solid motor mounts, frames twist, engines move, so you need something to give a little. It was routine to tighten them up every time a machine came in for service, until the clamps were bottomed out. Then you had to replace the gaskets, and start over.
I started modifying the exhaust systems by cutting off the tapered flanges, and replacing the fancy connector with stainless flex pipe and band clamps. Worked quite well, as long as you designed it so there was enough flex-pipe to flex. Besides lasting longer, it was cheaper. It became standard on most OEM designs later on. :)

Bill
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BadDog
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Re: Exhaust flange and gasket problems.

Post by BadDog »

All I can say with 100% certainty is that is the way it came to me installed on my new base rig. But it looked pretty Banks original with very little mileage on the vehicle, so I'm pretty certain it's Banks original.

And I agree with flat gasket not being a problem. My beef is that they used something that was never intended to be a flat gasket flange, and did a half-sssed hack job of making it work, with the subsequent complete lack of gaskets other than their very poorly fitted gaskets that blow easily due to all the missing gasket material from having a 2-9/32 hole instead of a 2"+ hole combined with lack of a flat flange surface.

And I had assumed the original significant bow was from welding and weak QA. But if I'm right, it was probably never flat enough to properly support a flat gasket to start with because it was made to simple lock a flare on a donut.

Anyway, I kept hoping to find a good gasket somewhere. Struck out in automotive, but maybe agg, industrial, whatever. But of course still struck out because it now seems that it effectively became a poor quality proprietary flat gasket flange. So I'll just have to make sure it didn't warp too badly, and make my own. In hindsight, I wish I had just gone that way to start with as you and others suggested. Oh well, I got there eventually.

Thanks for all the discussion on the matter, it really helped...
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Re: Exhaust flange and gasket problems.

Post by liveaboard »

I have exactly the same problem with an old boat I have; I bought a flange fitting muffler for it 20 years ago and made all the pipes fit, now I can't get that kind anymore.
So I cut off the flanges and welded the new muffler to them, but now I need to find square flange 4 hole exhaust gaskets and am not having success.
I'll try to source that material in the EU; I'm not so optimistic I admit.
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