XXO/BVGC '38 Chevy Coupe Build

[roygoodwin]

Wikipedia says that the melting point of copper is "1984.32 °F" while aluminum's melting point is "1220.58 °F".  (different alloys of either would be different ).  Sooo, the question in my mind is would the 700ish deg difference be a problem ?  I dunno, but something to think about.

roy

[charlie101]

There's also thermal conductivity that can play some roll in it, from what I understand copper has some 1/3rd better conductivity in hot state than aluminium. And Copper expands much less than Alu that with an alu gasket may impose some creep problem. A fiber gasket can allow a lot more shear movement than solid materials. Multi layer StainlessSteel gaskets can allow shear between the layers without breaking.

[38flattie]

Wikipedia says that the melting point of copper is "1984.32 °F" while aluminum's melting point is "1220.58 °F".  (different alloys of either would be different ).  Sooo, the question in my mind is would the 700ish deg difference be a problem ?  I dunno, but something to think about.

roy

Roy, I would think that if the melting point would be a problem, we'd experience the same problem with the heads, correct?

There's also thermal conductivity that can play some roll in it, from what I understand copper has some 1/3rd better conductivity in hot state than aluminium. And Copper expands much less than Alu that with an alu gasket may impose some creep problem. A fiber gasket can allow a lot more shear movement than solid materials. Multi layer StainlessSteel gaskets can allow shear between the layers without breaking.

I'm not too worried about the heat conductivity, as both the block and heads are water cooled. The added expansion could be a problem, but could possibly work in our favor- if we could get the torque right, the expansion could possibly help with sealing. I think!

I would love to use a fiber, or multi layer stainless gasket, but cannot get anyone to make one for us.

Aluminum is a lot softer than copper-maybe too soft is the issue? It may be that aluminum 'loses it's shape' after being torqued with the o-rings digging into it?

From Wikpedia- lead has a hardness of 5HB, aluminum 15HB, copper 35HB, and mild steel 120HB

So, some motorcycles run aluminum head gaskets, and a lot of cars have aluminum header gaskets. Does anyone know why aluminum isn't, or can't be used for head gaskets?

...Sorry, I don't necessarily always buy into the "if it worked, everyone would be doing it" thing!

[RichFox]

Well if aluminum is that soft, why do you need a head gasket? You have aluminum heads. I dropped my head gasket right after annealing it and that copper gets pretty soft. 

[38flattie]

Well if aluminum is that soft, why do you need a head gasket? You have aluminum heads. I dropped my head gasket right after annealing it and that copper gets pretty soft. 

Rich,

The heads are much harder than the soft material I am proposing. Plus, without a head gasket, not only would we lose our quench area, the pistons would hit on the heads!

Aluminum is cheaper than copper, plus Don can laser cut aluminum, but not copper.

From Don:

Anything that is reflective when it melts (copper, brass, lead, etc.) cannot be laser cut without special equipment that closes the laser shutter when strong reflections are seen. and each lens cost 600.00 plus 3 to 5 hr  to clean the mirrors after you blow one up --  and boy did we blow them up when we first got the machine ,, lol   

[Milwaukee Midget]

Heck, if you're going to laser cut your own gaskets, why not make yourself a set of mls gaskets?

Let's face it, with the capabilities you've already demonstrated, cutting six stackable embossed sheets of stainless shouldn't be that tricky.

[38flattie]

Chris, one of the issues is getting the material.

One of the advantages of using the aluminum, if we can get it to work, is being able to acid etch it, and get the bosses around the stud and water jackets.

Where's Fordboy? I'd sure like to hear his take on the use of aluminum for head gaskets!

[manta22]

Copper can be etched with ferric chloride.

[38flattie]

Copper can be etched with ferric chloride.

Thanks Neil!

The real issue with copper is the expensive upgrade that would need to be made to Don's machine, where he can cut up to .250 aluminum with no upgrade!

[Rex Schimmer]

Buddy,
You seem to be chained to Don's laser cutting machine, you could get the same accuracy and make the gasket from anything from aluminum to granite if you had them water jet cut. Accuracy is +or- .005 inch, not quite as close as a laser but certainly good enough for a head gasket. I really don't think that aluminum would make a good head gasket, I would assume that you would use 1100 or 3003 alloy, both of which can be annealed but again "if it is such a good idea why doesn't everyone use them?"

Rex

[38flattie]

Rex, I respect the fact that you, and others, don't think the aluminum is a good idea, and I'll admit to being hard-headed.

....But WHY isn't it a good idea?  I have no issue abandoning the idea, if I can find empirical data proving it worthless, or real experience of others that have tried it and failed.

As for "if it is such a good idea why doesn't everyone use them?", I see a lot of things tried successfully on the salt that everyone knows won't work! Talk to Kenny Kloth sometime-he did a lot of stuff to his old flathead that doesn't work, except it did!

We're not chained to Don's machine, but it sure would be cheaper and easier!

[tauruck]

Dang, I'd love to be chained to any machine right now!
Buddy, you'll get it figured. 

[desotoman]

Buddy,

Many years ago Kong Jackson made some aluminum head gaskets for the Ford Flathead. He sold them to some of the guys back then. I think McCain & Houtz bought some and tried them, so you might contact them and ask their opinion, or ask if they knew of someone that has run them.

I was lucky enough to buy some of Kong's first run which were copper head gaskets, so I never bought the aluminum ones, which were the second run of gaskets he made.

Tom G.

[38flattie]

Thanks Tom!

Any idea on how to contact them?

EDIT: I just remebered Jimmy Stevens used to be hooked up with them, so I have a call in to him. I'll let you know his thoughts on the head gaskets!

[desotoman]

Buddy,

I think they are in the Super Fours Car club, so I would start there. I don't have a current contact for them.

Tom G.