Wanted I need a part made...

[ragnarok]

I have no idea if this would be the proper forum for my request, but here goes. I have an odd problem with my sports car; the aftermarket and factory exhaust flanges don't line up quite correctly. They are not parallel to each other. The bolts and pipe line up fine, but the gap between the flanges is wedge shaped. So what I want is an exhaust gasket made with the wedge shape built in. (I figure this solves the issue without removing anything from the car.)

I have attached a quick schematic of the dimensions of the gasket. I don't care what material is used, as long as it can stand up to the heat of a non-turbo exhaust header and the environment of the underside of a car. IF more dimensions are needed, I assume someone will let me know.

The "wedge" part: The tricky part is building the wedge shape into the gasket. In the drawing, Edge A needs to be 1/16", and then thicken in a direction perpendicular to that edge, across the part to Edge B, which needs to be 1/8".

I am willing to pay whatever for your time and material, of course.

Edit: I need two of these. Dual exhaust, both flanges have this issue.

 

[TonyM]

Why not make a wedge shaped spacer, say from aluminium, and use ordinary gasket material. Also it would help if folks knew where you were located.

edit. I see you are from Ohio in another post.

 

[danallen]

Why not make a wedge shaped spacer, say from aluminium, and use ordinary gasket material.

It would likely need a gasket on both sides of the spacer but it's the way I would try.

 

[stevehuckss396]

I agree with the comments above. Seems like a wedge shaped gasket would eventually be pushed out. A wedge with 2 gaskets seems like it would have a longer life.

 

[ShopShoe]

Partially OT post follows:

Been there, done different. It was in the 1990s: I don't know what is possible nowadays. For a temporary fix, I got some exhaust patching material from my local auto-parts store, and extra gaskets. I built up a sandwich of gaskets and patch material in the wedge shape. I can't remember, but I may have had a heat-proof sealer in there somewhere as well. It only lasted a few months, but it kept my daily driver on the road.

Just a thought: Is the flange on the pipe thick enough that you could grind it to fit with an Angle Grinder and still have enough meat to clamp up all right?

Another thought: Did you keep the old part? Could you cut off the flange and mill it to fit the profile? No old part - perhaps someone else has something with a flange that could be cut off and modified. Well-stocked muffler shops also used to have flanges for welding up custom assemblies.

--ShopShoe

 

[SmithDoor]

I have no idea if this would be the proper forum for my request, but here goes. I have an odd problem with my sports car; the aftermarket and factory exhaust flanges don't line up quite correctly. They are not parallel to each other. The bolts and pipe line up fine, but the gap between the flanges is wedge shaped. So what I want is an exhaust gasket made with the wedge shape built in. (I figure this solves the issue without removing anything from the car.)

I have attached a quick schematic of the dimensions of the gasket. I don't care what material is used, as long as it can stand up to the heat of a non-turbo exhaust header and the environment of the underside of a car. IF more dimensions are needed, I assume someone will let me know.

The "wedge" part: The tricky part is building the wedge shape into the gasket. In the drawing, Edge A needs to be 1/16", and then thicken in a direction perpendicular to that edge, across the part to Edge B, which needs to be 1/8".

I am willing to pay whatever for your time and material, of course.


View attachment 136140

It is a simple part I think most have made that part.
It something that found on most engines.

What part of world are you in?

Dave

 

[ragnarok]

I appreciate the variety of responses. To answer a few questions:

I am in Toledo, Ohio.

I am a huge fan of this forum and the engines you guys build, been here since 2014, but I have no machining capability of my own.

The plan is to put a gasket on either side of this wedge, yes. Already have them. It's fine with me to make the wedge from aluminum. I just called it a "gasket" in my original post for convenience.

To address ShopShoe's thoughts: you are right, the "proper" way would be to cut off the flange, bolt it to the other flange, and then weld it back on to the pipe at the correct angle. Also, there is enough flange thickness on the header side to grind/mill it down to the correct angle. I wanted to try the wedge-with-gaskets approach first because:

1) It's the easiest option for me. No taking the car to a shop and finding a way home while they work on it; no removing the header (a real pain) and/or exhaust for grinding/chopping/welding, I just get this wedge made and jack the car up and bolt it in. voila!

2) This option leaves all the relevant parts on the car stock.

3) I thought it would be more interesting to enlist the help of you guys. This wouldn't be the first part on this car custom made by a guy at home in his shop, and I imagine it won't be the last.

4) I forgot to mention in my first post, this is a dual exhaust, both flanges have this issue, so I need two wedges, and it saves me twice the work.

 

[SmithDoor]

I appreciate the variety of responses. To answer a few questions:

I am in Toledo, Ohio.

I am a huge fan of this forum and the engines you guys build, been here since 2014, but I have no machining capability of my own.

The plan is to put a gasket on either side of this wedge, yes. Already have them. It's fine with me to make the wedge from aluminum. I just called it a "gasket" in my original post for convenience.

To address ShopShoe's thoughts: you are right, the "proper" way would be to cut off the flange, bolt it to the other flange, and then weld it back on to the pipe at the correct angle. Also, there is enough flange thickness on the header side to grind/mill it down to the correct angle. I wanted to try the wedge-with-gaskets approach first because:

1) It's the easiest option for me. No taking the car to a shop and finding a way home while they work on it; no removing the header (a real pain) and/or exhaust for grinding/chopping/welding, I just get this wedge made and jack the car up and bolt it in. voila!

2) This option leaves all the relevant parts on the car stock.

3) I thought it would be more interesting to enlist the help of you guys. This wouldn't be the first part on this car custom made by a guy at home in his shop, and I imagine it won't be the last.

4) I forgot to mention in my first post, this is a dual exhaust, both flanges have this issue, so I need two wedges, and it saves me twice the work.

This maybe the right gasket.
I use to by gasket material from Pep Boys off rack.

Dave

https://www.mcmaster.com/3572T13

 

[HMEL]

I would not use aluminum for an exhaust gasket. The temperatures would be way to high for that service. Although these are simple systems they need to be fitted properly because of the carbon monoxide issue not to mention what the hot gases will do in that location. There are forces generated due to the expansion of heat including the bolts. The probability is high it will not stay together. The question I would want to know is why the alignment is not correct or rather what caused it. Carbon steel wedges can be fabricated but you will have doubled the possible leak area. I would be tempted to cut the flanges free bolt them in place and weld the pipe back using a sleeve to correct the misalignment. The are other ways of correcting it and none of them easy. It depends on how much value you are placing on this car.

 

[Circlip]

How can the 'Wedges' be pushed out? Don't the two mounting bolts interfere with this?

Regards Ian.

 

[stanstocker]

I have no idea if this would be the proper forum for my request, but here goes. I have an odd problem with my sports car; the aftermarket and factory exhaust flanges don't line up quite correctly. They are not parallel to each other. The bolts and pipe line up fine, but the gap between the flanges is wedge shaped. So what I want is an exhaust gasket made with the wedge shape built in. (I figure this solves the issue without removing anything from the car.)

<snip>

For a different approach, is there a real auto repair place near you? Some still bend exhaust pipes to fit. It sounds like you have a bend in your pipe that needs a wee tweak. Down the road, having things line up nicely will avoid going through the entire process all over again. Might even be easier to have them fabricate an intermediate pipe or modify what you have to use floating rather than welded in place flanges.

Cheers,
Stan

 

[ragnarok]

Doesn't matter to me what material is used. Whatever the maker has lying around his shop is fine. If he wants to use steel, to avoid any question of whether an aluminum wedge would melt, that's fine.

 

[Joe]

Rotary engine ?

 

[SmithDoor]

Doesn't matter to me what material is used. Whatever the maker has lying around his shop is fine. If he wants to use steel, to avoid any question of whether an aluminum wedge would melt, that's fine.

I used punches like this and in just few minutes have gasket made. When doing a lot of rebuild I purchased unto 2 1/2" and few rolls of different gasket materials.

Dave

https://www.mcmaster.com/3427A36/

 

[Steamchick]

On the subject of aluminium as a spacer here: It should be OK - on the premise that heat would quite readily flow into the cylinder head - which may well be aluminium? While the exhaust gases at this point are around 800~900deg.C. the gas flow allows for the surface of the aluminium to be at below 500dec.C - sort of region... thus - like the pistons - the aluminium doesn't erode or melt.
I guess the 2 studs/bolts would prevent the tapered spacer from popping-out?
BUT: I would be concerned that differential expansion (and thickness) of the joint (spacer) between Nuts and face of the cylinder head would cause excess stressing and possible bolt breakage, distortion (creep) of the aluminium, or failure of the gaskets. Therefore for this reason I think a steel spacer is favourite?
Also: The original design of the short studs in the cylinder head - with the (steel?) manifold flanges clamped under the washers and nuts - should be replicated to maintain the joint design integrity.
Incidentally, is this a cast manifold or steel tube design? Cast manifolds do creep with time, as the metallurgy of the cast material changes with the high temperature, varying temperature, and cold-hot-cold cycling. A typical 2 litre car engine (2, 3 or 4 ports) with cast iron manifold can "grow" - or shrink - by 1/4" or more after 100,000miles... (witnessed on cast iron and SG iron manifolds after full-life durability testing of engines). SO Gasket materials for this application, and stud/bolting arrangements, washers, holes, etc., are specifically designed to permit the surfaces to slide and allow growth or shrinkage with temperature and ageing. Parallel faces permit this, but the tapered "Wedge" spacers may not? SOME gaskets for this application are effectively steel shims, with a carbon interface (making a steel-carbon-steel sandwich) so that when clamped-up. the joint is gas tight, but the shear forces on the joint permit the manifold face to slide relative to the cylinder head.
Sorry if all this sounds "too technical", but there are some risks associated with the tapered spacers, and it should help your decision making if you have some idea of why parallel faces are a "better job".
K2

 

[ragnarok]

Rotary engine ?

20 year old 2.8l NA straight 6 in a state of tune maybe 10% higher than stock.

On the subject of aluminium as a spacer here: It should be OK - on the premise that heat would quite readily flow into the cylinder head - which may well be aluminium? While the exhaust gases at this point are around 800~900deg.C. the gas flow allows for the surface of the aluminium to be at below 500dec.C - sort of region... thus - like the pistons - the aluminium doesn't erode or melt.
I guess the 2 studs/bolts would prevent the tapered spacer from popping-out?
BUT: I would be concerned that differential expansion (and thickness) of the joint (spacer) between Nuts and face of the cylinder head would cause excess stressing and possible bolt breakage, distortion (creep) of the aluminium, or failure of the gaskets. Therefore for this reason I think a steel spacer is favourite?
Also: The original design of the short studs in the cylinder head - with the (steel?) manifold flanges clamped under the washers and nuts - should be replicated to maintain the joint design integrity.
Incidentally, is this a cast manifold or steel tube design? Cast manifolds do creep with time, as the metallurgy of the cast material changes with the high temperature, varying temperature, and cold-hot-cold cycling. A typical 2 litre car engine (2, 3 or 4 ports) with cast iron manifold can "grow" - or shrink - by 1/4" or more after 100,000miles... (witnessed on cast iron and SG iron manifolds after full-life durability testing of engines). SO Gasket materials for this application, and stud/bolting arrangements, washers, holes, etc., are specifically designed to permit the surfaces to slide and allow growth or shrinkage with temperature and ageing. Parallel faces permit this, but the tapered "Wedge" spacers may not? SOME gaskets for this application are effectively steel shims, with a carbon interface (making a steel-carbon-steel sandwich) so that when clamped-up. the joint is gas tight, but the shear forces on the joint permit the manifold face to slide relative to the cylinder head.
Sorry if all this sounds "too technical", but there are some risks associated with the tapered spacers, and it should help your decision making if you have some idea of why parallel faces are a "better job".
K2

I appreciate the detailed information. It's a stainless steel tube header. This wedge isn't going against the head, it's going between the header and the factory exhaust. Here is another quick sketch to clarify what I am asking for:

 

[dnalot]

Have you considered bolting the flanges together and then heating the factory exhaust tube up to red hot a few inches from the joint.

Mark T

 

[ragnarok]

Have you considered bolting the flanges together and then heating the factory exhaust tube up to red hot a few inches from the joint.

Mark T

That's an interesting thought. I would be afraid the tube would fold/tear in ways I don't want it to. Have you done something like this before? Would a MAPP gas torch be sufficient for that?

 

[dnalot]

That's an interesting thought. I would be afraid the tube would fold/tear in ways I don't want it to. Have you done something like this before? Would a MAPP gas torch be sufficient for that?

If you are only closing a .063" gap there should be very little if any deformation of the tube. I have done this on marine engine manifolds many times without any trouble. I do not know if MAPP gas would get the tube as hot as you need. But two Mapp torches might. If you can get a red spot all the way around the tube one side will stretch a little and the other side would compress a little.

Mark T

 

[ragnarok]

Hmm. I may pick up a 2nd torch and try that out.