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Exhaust Manifold to Pipe Flange Gaskets


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So I'm in the process of revamping my exhaust. I've taken the ASV brackets off of the exhaust manifold, and I'm going to extend my Y-pipes up to the engine itself without the brackets. I took the old crusty gaskets out, and I'm buying new ones. But all of the gaskets that it seems I can order are just simple rings, whereas the ones that I took off were the shape of the pipe flanges on my Y-pipes. My engine is an EA81 on my '83 BRAT. What kind of gaskets do you guys have at this spot? Will the simple, circular ones work? My whole point of working on the exhaust in the first place was to keep it from leaking right at this spot, so I want something that will hold well.

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Oh, but wait, that's the gasket for the rear exhaust, I already have some of those. I'm talking about the gaskets for the front exhaust where the Y pipe connects to the outtake manifold on the engine. The bolt hole centers have to be 3" apart, not 3.5" and the opening about 2" only.

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Wait a second... You want to take the exhaust 'manifolds' off and bolt your exhaust straight to the head? Not a good idea if that's what you're doing. Those are not only there for the emissions piping, but to direct and dissipate heat away from the head. Removing them would most likely cause the flange on your Y pipes to warp and possibly cause some head or valve issues in the long run. I could be wrong and someone here may have done it with no issues, but as I understand it, with my basic knowledge of engine design, they need to be there.

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I am almost ready to go with a dual exhaust system with small glass-pack mufflers.

I'm going to use flex exhaust tubing from the heads to the firewall, then hard pipe to the glasspacks in the rear.

The reason for the flex is so that if/when I off-road, the engine can jostle all it wants without compromising the exhaust, and it probably will not weigh more than that old battleaxe "Y" that I have never liked anyway.

I am disappointed in that I have the opportunity to effectively install headers in this, but the damned ports coming out of the exhaust are still only 1 7/8" maximum I think.

The standard muffler/glasspack is 2" so I had to get 2" flex. and will have to get 2" hard tubing, and could have done larger except that I have heard that these 2nd Gen Subarus need a certain amount of back pressure for reasons I did not bother to remember....

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Wait a second... You want to take the exhaust 'manifolds' off and bolt your exhaust straight to the head? Not a good idea if that's what you're doing. Those are not only there for the emissions piping, but to direct and dissipate heat away from the head. Removing them would most likely cause the flange on your Y pipes to warp and possibly cause some head or valve issues in the long run. I could be wrong and someone here may have done it with no issues, but as I understand it, with my basic knowledge of engine design, they need to be there.

 

Hmmm... This makes no sense. Most Subarus have their exhaust manifold bolt directly to the head. There is certainly no warping or head/valve issues. If fact I do not believe the ASV (or is it AIS - air injection system?) was used outside of the US. 

 

I doubt there would be any issues removing the spacers, except perhaps for pollution/emissions.

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One difference between 1st and 2nd Gen Subarus is that in most 1st gen models the exhaust really was bolted directly to the bottom of the heads, whereas with most 2nd gen models, there was at least a square steel block between them, which I think may have/had some port in them. These made fixing an exhaust at the heads a lot easier.

Maybe that is what is here being referred to as some type of manifold, or is this confusion about the "Y" ???

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No, that little piece is the 'manifold'. Odd they never did that down under. I seem to recall a couple early EA81 Brats I had with no ASV and they had the manifolds. I honestly don't remember if either of my Gen1 Brats had them or not, but I've never seen an EA81 without them.

 

Subaruist..... As for dual exhaust. Don't bother. You will yield no more useable horse power and actually decrease what useable low end torque the motor had to begin with. Flex tubing..... Another waste, especially on an off road rig taking abuse. I experimented with that stuff back in the day. There's a reason it's never gone mainstream. It's all made of crappy low grade steel with some other metals mixed in to cut costs. It doesn't hold a weld very well. Also, the actual spiral winds of the tubing are formed from very thin, flat steel. This again makes welding fun and if you're off roading and your exhaust meets the proverbial immoveable object, guess what.... RIP! I have this on first hand experience. Clamping will only hold so long in an off road situation as well, Again, because it's thin and moves a lot it will eventually loosen. If the exhaust is hung correctly and has the correct joint at the y pipe to rear section, you won't have any issues.

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I have chosen Dual exhaust out of mostly preference. I like the idea, it was simpler than dealing with replacing the "Y", I like glasspacks, etc. - It has very little to do with performance, but with such small exhaust ports, I guess it really doesn't matter anyway.

 

I did check out one of those exhaust modules for an alternative flex, which essentially used tightly woven and layered grounding-strap looking wire mesh, and was way too stiff, and not something I want to use.

Flex - I really don't care what the inferiorities are, its about off-roading and the engine. If it it compromised, I will replace it, its cheap.

I do not plan on welding it, but will do more than just a clamp. I have special clamps in mind. I will also be using some compound normally used for patching a muffler to help seal up where I "clamp" it. If I can manage it, nothing else will be welded either. There are applications where welding is best, but when it somes to Exhaust, I don't like it.

You can't fix damage without the assumption that you will have to have it welded again; it is definitely not good for out-in-the-middle of nowhere improvised repairs.

I am also going to be looking for what we used to call "Asbestos Substitute Gasket Material" to help protect the inside of the flex, just as an experiment. These exhausts will also likely be better protected than normal; that is something I am working on as well.

 

Flex is every bit as bad as you say, but I want something that will give absolutley no resistance or torque whatsoever to the engine/Exhaust ports, and nothing else is better for that that I know of so far.

I wanted to use the old "Form-to-Fit" bendable exhaust tubing that you could bend yourself over your knee, but after exhaustive research, word from the experts is that it has not been available for around 30 years. Damn, that makes me feel dated. I know what I need, but it has not existed for 30 years, lol...

- But I need it, dammit! lol...

Edited by Subaruist
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ea81 turbos don't have the spacers and neither do the non-catalyst ea81's.

I did not know that. lol The turbo that is. The one turbo EA81T I had got little to no attention between the time I picked it up til the time it rolled out of here. I still recall one of my first second gen Brats not having any of the wonderfully inventive government emissions crap and still having the manifolds. Only because I fought exhaust leak episodes like the zombie apocalypse. lol Then again, that was 20 years ago so..... It does make sense they added them for the ASV rather than rework the head to accommodate the Feds. And Subies aren't your normal engine. lol

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I do not believe the ASV (or is it AIS - air injection system?) was used outside of the US. 

 

I doubt there would be any issues removing the spacers, except perhaps for pollution/emissions.

 

Just have to state I am wrong with that statement! Seems the spacers were certainly used outside of the US from photos I have seen online but I stand by the idea they are not necessary and you can run without them.

Edited by Leeroy
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  • 2 months later...

Thanks turbosubarubrat for setting my mind at ease regarding the spacers. Sadly, since I'm so new at all of this, I ended up doing a poor job with the exhaust so my pipe flange on one side doesn't fit snug and I have a worse exhaust leak than before I ever started any of this, ha ha. 

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Wait a second... You want to take the exhaust 'manifolds' off and bolt your exhaust straight to the head? Not a good idea if that's what you're doing. Those are not only there for the emissions piping, but to direct and dissipate heat away from the head. Removing them would most likely cause the flange on your Y pipes to warp and possibly cause some head or valve issues in the long run. I could be wrong and someone here may have done it with no issues, but as I understand it, with my basic knowledge of engine design, they need to be there.

 

Anh.....they are just there to divert Exhuast for the ASV pipes.

 

EA82's and all EJ engines the pipes mount straight to the head.....no problems with this.

 

They don't need to be there.

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  • 3 weeks later...

I've got one for you...

 

How about Handicapped bathroom wall bar exhaust adapter?!?

I was at a thrift store,looking at some stainless rails/bars used in bathrooms for the handicapped. These were the kind with the wall mounting flange fitted/soldered/welded on the end for direct bolting to the wall, and seeing if I could use them for something else, when I noticed how close they seem to come to something one could mount to the bottom of the engine block with a couple of holes drilled and maybe some kind of improvised gasket ! If I could afford to somehow do the whole dual exhaust system I want for my own Brat, I would love to do it all in stainless steel tubing! lol. - and yet I wonder.... Hmmmm....

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To actually address your original post, in the old days I had to deal with the exhaust coming out of the bottomof the engine on my 1st Gen. Brats. Gaskets were also a problem for me. I had no money to speak of so I had to improvisse.

One temporary stop-gap (lol) measure was that I rolled aluminum foil around an empty toilet paper roll, then wound some wire, thinner than bailing wire around it, only a very few turns down the length of it, then more aluminum foil.

I then scrunched it all down so that instead of making a tube, it was a little closer to a donut shape.

This would seat well into the recess in the engine side and over the little nub of and end of the exhaust pipe, and when I assembled and tightened it, it would crush into place and into shape. This was only temporary.

I assume by now you have solved your problem, and the previous idea would probably not work for you, but thought I would throw it out there in case it gave you some idea.

 

Closer to what you are actually dealing with - I am not sure what they are calling the stuff these days, but way back when, when they had recently banned asbestos for anything, they came out with what they called "Asbestos free gasket material", I think it was meant for head gaskets. It was similar to really hard, dense cardboard as far as working with it was concerned. You should be able to make your own gaskets out of it. Ifi t is not thick enough, I might suggest using more than one layer, glued together with High-Temp silicone gasket sealer. This way, you could have one layer the shape of your flange, one or more layers to fit into any recesses, and again a layer the shape of the other fitting/flange, thus having something extremely custom and tailored exactly to your interfaces/flanges/etc.

 

 

Just something to improvise,in case you are still having the difficulty.

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  • 7 months later...

what is this spacer thing?  All I've noticed is the Y pipe bolt directly to the head.. Never seen anything between the two...I thought the Y pipe was the exhaust manifold. 

The "Spacer" referred to is a steel casting designed to allow what we in Australia call an Exhaust Gas Recirculation Pipe to be fitted into the system, They were bolted to the head and then the exhaust bolted to them, That is why the later Cylinder Head castings had four bolt holes at the exhaust flange instead of just two,But be aware if removing them the exhaust studs when fitted after removing the EGR takeoff spacers are only about 10~12mm into the head casting most Exhaust studs are about 1.5 times the depth when fitted into an alloy casting so they can and do strip the thread in the head if not careful.

 

I upgraded mine with Wurth Timeserts for that reason, I did not have a head to cut up to see if I could drill them deeper for more thread engagement hence the Timesert upgrade.

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  • 1 month later...

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