Casting aluminum

Does anyone know what grade of aluminum is used in cast valve covers? How about intake manifolds or flatheads?

 

I'm guessing you could find the info in an Edelbrock catalog.
They talk about their foundry and I believe I saw a comment there about what alloy they use.

I'm guessing as well that a fairly pure form of aluminum wouldn't work well.
I have some of that and it's useless because it doesn't machine well.

Run some tests with the commonly available 6061 T6 and see how it does.
Probably melts at a slightly higher temp than pure aluminum.
Not sure how the T6 (stands for temper & hardness) works out after being cast, but it has to be better than the 5054 T4 a supply outfit palmed off on me with the reccomendation that it "machines great."
BS - machined like frozen peanut ****er.
Which is to say it ripped and tore instead of cutting smoothly.

Made a helluva billet doorstop though....

 

Check out Lindsay books. They have alot of really good books and manuals on home casting. I bought a reprint of an old Navy training manual for shipboard casting of parts. It was written for the sailors so there's not alot of theory, just practical knowledge. I'll probably never get into casting metal parts, but it's nice to now how it's done.

 

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Does anyone know what grade of aluminum is used in cast valve covers? How about intake manifolds or flatheads?

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I believe that it's usually A356. That's what most castings are poured from.

However, it could be almost any type: 6061 , 7075, 5252, 3003, 711, 713, 771, 356 T-6, 319, 535, 850.1, 852, B443, C355, 242, A707, 2024, 7075 T-6, 7075 T-7 or 8011.

Were you just curious, or were you trying to match something?

--Matt

 

Well I happen to have it on authority from the owner that all of the Hemi valve covers done by O'Brien Truckers are virgin 319 alloy!

Dennis (CMFIC)

 

Here's a manufacturer mentioning 356 and 319 for intakes

Hayes Lemmerz

And if ya really want all the details on aluminums look here

MatWeb

 

Wow, thanks, folks. I've been out of town all weekend so this ended up on page 4.


The place I just started working has a (I'm almost scared to mention it on the board) foundry. All kinds of stuff ran through my head....primarily a S8 Buick valve cover and side plate.

 

FAB - Most aluminum castings are 356-T6. The 356 material is cheap, common, and works well. The T6 stands for a heat treat, which is done after the parts are cast. Porosity has been a large problem with all of the cast aluminum parts that I have designed. Most of these problems have been solved by altering the gating used during the pouring process. However, I think the problem is ultimately due to design -- large, thick features next to thin walls tend to be affected most. That being said, I've had porosity appear in the wierdest spots; recently it turned up on a web that joined two larger parts... usually I find the flaws on the larger feature.

Someone else on here (like Dennis) probably has a lot more experience with casting than I have. So far I've only designed maybe a half dozen cast aluminum parts.

Anyway, I'm rambling. Hope you found something usefull.


Ed

 

I want to add one more thing -- the heat treat is absolutely necesary. Without it, the aluminum is "gummy" when machined. We've tried to machine partially heat treated parts with poor results.

OK, one more thing -- Add AT LEAST 3/16 of extra material to every machined surface. On bores or ODs, add 3/16 to the radius (not the diameter). Much of that 3/16 will have to be machined away just to get a flat surface before you're even worrying about the final dimension.



Ed

 

I know billet can be a bad word around here . . . which strikes me funny that someone would be bothered by that in view of all the other bad words floating around here....

Anyhoo - why not knock out a cover from aluminum plate that looks similar to the race-o covers welded up by a lot of race oriented shops and suppliers?

A 3/8" flange would be easy to do and would allow for machining to flat after welding.
Bolting it to a spare or removed head for the welding process would help, but better yet would be a flat steel surface.
Drill and bolt it to your flat steel welding table?

Some 1/8" side and end pieces - make these from four pieces or two pieces with appropriate bends.
A 1/8" top either flat or better yet, a couple of bends in it similar to some of the BBC welded alloy covers.

If you don't weld aluminum, but you can tack it, do that and take it to an experienced aluminum welder.

I wouldn't be afraid to tackle this one with a gas welder....

 

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I know billet can be a bad word around here .

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Actually you could call those sheet metal or fabbed and then it would be totally acceptable.
The ultimate cool way to do it is mount your flange to the inside, then weld some tubing between the gflange and the tops where the bolts p*** through. It makes the covers look huge which in turn makes your engine look bigger.

Fat***buick sorry I have no answer for your question the only casting I have ever done was in a shot cast foundry and I now absolutley nuthin' about the subject.