gasket in exhaust

[Guest Ken G]

In my 1925 Rover, there is a gasket between the exhaust manifold and the flange at the end of the exhaust pipe. The surfaces between which it fits are nominally flat, but over the years they have developed imperfections, and I don't want to remove the manifold to have it machined because that would merely set me problems sealing at the cylinder head! In only a few miles I have gone through two modern Ford gaskets (which look like asbestos but are presumably not). I am told I need a copper gasket that will shape itself to the slight irregularities of the surfaces.

Does anyone know where I can obtain or have made a suitable copper gasket? Alternatively, assuming I can obtain some sheet copper, would it be adequate merely to cut out a gasket with tin-snips or a hack-saw? I suppose I could try and see, but I would appreciate the benefit of anyone's experience before I have a go. There are only two bolts, so it's not obvious that tightening them will produce a more or less uniform pressure all round the gasket.

Ken G, 1925 Rover 16/50 (San Francisco)

[RoadsterRich]

Have you checked with Olson's Gaskets?

http://www.olsonsgaskets.com/

They have had most all of the gaskets I've needed for the Chrysler 77.

Rich

[Guest Ken G]

Rich, Funny you should ask that, in that just before I posted my query I had sent Olson's an email. Their web-site gives no indication that they might have copper gaskets but I don't think it admits to crush washers either, and they have those. We shall see.

Ken G, 1925 Rover 16/50 (San Francisco)

[Peter J.Heizmann]

Hi, Ken...

Just my thoughts should Olson's generates a negative response.

As you mentioned the concern that there are only 2 bolts, thus, a uniform pressure would not seal. If you cut copper gaskets out of stock sheets, measure as best you can the existing gap. Use a heavier gauge copper to take up the gap, and, the 2 bolts & heavier gauge should be more uniform.

i.e...you have a current gap of .030" tightened. Go with sheet at .040/.050".

I am certain someone with more experience will chime-in shortly.

Regards, Peter J.

[Guest imported_oldmitchell]

Ken

The British cars typically use a sandwich type of gasket. A thin layer of copper on each side with asbestos(?) between. I do not believe a single sheet of thick copper will compress enough to seal very well.

[RoadsterRich]

Olson's had the exhuast flange gasket for my 30 Chrysler 77. It was made almost exactly the same way my head gasket, intake and exhaust manifold gaskets were made. All of them appear to be a flexible very soft (but not extremely thin) sheet of copper adhered to both sides of a softer material, presumably at one time asbestos, though with modern restrictions I'm not sure what they use now as a replacement. It seems to seal the exhaust quite well, and I have the similar pitting issues on the manifold flange.

Rich

[Guest Albert]

You might be able to use a piece of 1 1/2" of 2" copper pipe sliced and flattened, then trim to shape, once it is shaped heat it cherry red and drop into water to make it soft. have made motorcycle head gaskets up this way and have worked out better than the original. have you tried the red high heat silicone sealer?

[Guest Ken G]

Many thanks to you all.

Sandy Olson did indeed respond offering "an asbestos material in several thicknesses". I didn't take this to mean a copper-clad material, but perhaps it is. I will inquire further.

The idea of taking a piece of thinnish walled copper pipe and flattening and annealing it is ingenious and certainly worth considering. (Incidentally, surely annealing copper does not need quenching; once it has been heated above a critical temperature, it doesn't matter how it cools, because the hardening is caused by working, not by the manner of cooling, unlike steel).

This gasket problem at least can certainly be solved at reasonable expense. I wish I could be sure my oil pressure problems were as easy!

I will report further progress.

Ken G, 1925 Rover 16/50 (San Francisco)