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| Aluminum Head?! (Robert Maw) https://slantsix.org/forum/viewtopic.php?t=64918 |
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| Author: | GregCon [ Thu May 28, 2020 3:55 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Casting an aluminum head is quite difficult if you are required to end up with a head that is 'quality'. Bear in mind many of the big makers have trouble with casting heads...and they know what they are doing and have lots of experience. Mopar W5 'race' small block heads, for example, look gorgeous...but they are well know for having porosity problems. It's no fun assembling a set of heads, installing them, and thinking you are gonna go for a cruise when you find yourself with an oil pan full of water instead. I'd guess a straight six head is all the more difficult as it's even longer. I gotta say, if I were making a head from scratch for the Slant I'd be really tempted to put the exhaust ports on the other side... |
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| Author: | Tim Keith [ Thu May 28, 2020 6:00 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Quote: Casting an aluminum head is quite difficult if you are required to end up with a head that is 'quality'. I wouldn't want to cast a head, but attempt to cast a rectangular block that someone like Robert Maw could work with. A hunk a chunk of burn'n! If it can't work, then that's just the way it is. A "bathtub" concept is a pretty thick head in which the water passages are milled and drilled, then sheet metal is welded over them. I call my stuck-inside-my-brain design a "fat head" because the side with the ports is raised and there is more water inside. It is pretty conservative, but it requires a different intake manifold as the intake ports are raised and straightened. The exhaust ports are in the same location as now. The valve cover gasket flange might be raised a little. I have no idea what Mr. Maw has cooked up, and I don't intend to do anything with the idea in my brain. But, if someone could make a few raw castings that Maw could work with, just maybe the cost could drop under $3,500.
Bear in mind many of the big makers have trouble with casting heads...and they know what they are doing and have lots of experience. Mopar W5 'race' small block heads, for example, look gorgeous...but they are well know for having porosity problems. It's no fun assembling a set of heads, installing them, and thinking you are gonna go for a cruise when you find yourself with an oil pan full of water instead. I'd guess a straight six head is all the more difficult as it's even longer. I gotta say, if I were making a head from scratch for the Slant I'd be really tempted to put the exhaust ports on the other side... |
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| Author: | GregCon [ Thu May 28, 2020 7:17 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
A piece of 7075 aluminum 'billet' big enough to make a cylinder head would cost around $325. About 70% of it would end up in the scrap bin. |
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| Author: | jcc [ Fri May 29, 2020 7:36 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
FWIW, alum machine shavings are worth at the scrap yard in the $.03(?)/lb range. We just throw them away, as its often not worth the gas/time to transport, and heaven forbid, the shavings get "contaminated" with ANY steel/metal shavings before presenting to the scrap yard. |
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| Author: | Tim Keith [ Fri May 29, 2020 2:26 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Quote: A piece of 7075 aluminum 'billet' big enough to make a cylinder head would cost around $325. $325 isn't as costly as I would have guessed.
About 70% of it would end up in the scrap bin. |
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| Author: | emsvitil [ Fri May 29, 2020 2:47 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Do they have a 3D printer that works with aluminum? |
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| Author: | justa170 [ Sat May 30, 2020 8:07 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Quote: Do they have a 3D printer that works with aluminum? No idea, but he hasn't mentioned printing anything, as far as I know. He's starting with big aluminum bricks to machine prototypes out of, which I suppose is the opposite of "additive" fabrication. I don't know if the production shop(s) he has in mind will use other manufacturing methods.
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| Author: | Tim Keith [ Mon Jun 01, 2020 8:57 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
I visited the foundry. There was not much to see. His furnace is below ground level so two men can more easily lift the crucible. It was fueled with propane and was melting brass in an investment casting using a large amount of wax. He gets his supplies from this company : http://www.porterwarner.com/ |
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| Author: | GregCon [ Mon Jun 01, 2020 9:49 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
You'd be starting with a solid block of aluminum at around 100lbs. New aluminum, around here, sells for $3/lb, give or take. I'm estimating you'd machine away 70% of it, give or take. Since aluminum weighs 1/3 as much as iron (approx.) you'd end up with a head that weighed (about) 25lbs. instead of the 76lbs. of the iron head. There is some slop in all those numbers but they'd be close. There are a few places where you need to use thicker aluminum than you would cast iron so that's why I'm thinking the final bare head would be around 30lbs. |
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| Author: | jcc [ Mon Jun 01, 2020 11:28 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Maybe I'm confused, there is consideration of doing a private DIY alum casting for a Slant head? I was always under the impression doing alum castings was always fraught with downsides. Eldebrock after decades of casting now is doing high pressure cast alum castings, far beyond what any small production shop could ever affordably attempt. I think prior to high pressure, centrifugal casting was attempted. Billet has to be the only reasonable solution, and two part would solve some problems, while adding slightly to the fabrication. Taking off 45? pounds, high up ( above COG), in the front of the car, on a light car to begin with, is a very significant improvement, beyond the drag strip especially, IMO. |
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| Author: | Tim Keith [ Mon Jun 01, 2020 11:52 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
I'm sure a casting would result in a lot of scrap castings! I think many production cylinder heads have been cast with a semi permanent molds, then lost foam became popular, but I'm definitely not the one to know. On a casting forum someone once asked about casting a cylinder head and some of the professionals said it might be possible but don't be disappointed if the effort didn't take 3 or 4 years before you got decent quality with homemade patterns and methods. Which is to say, I've never heard of anyone being successful. But some have produced intake manifolds. |
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| Author: | slantzilla [ Mon Jun 01, 2020 5:14 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
I had a discussion with Doug when he was trying to get a head project going. IIRC, he said you had to be prepared for at least the first 10 castings to be junk, plus you had to cut some good ones apart just to see what was happening. |
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| Author: | Tim Keith [ Mon Jun 01, 2020 7:36 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
Quote: I had a discussion with Doug when he was trying to get a head project going. IIRC, he said you had to be prepared for at least the first 10 castings to be junk, plus you had to cut some good ones apart just to see what was happening. I think you could achieve OEM quality for the '70s, or maybe you could successfully develop patterns that a commercial foundry could use.These old heads worked and I'm sure the production methods weren't very sophisticated. https://bangshift.com/bangshift1320/eba ... our-jimmy/ |
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| Author: | slantzilla [ Sun Jun 28, 2020 11:45 am ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
He posted yesterday he's going to do a billet block now. |
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| Author: | Reed [ Sun Jun 28, 2020 1:10 pm ] |
| Post subject: | Re: Aluminum Head?! (Robert Maw) |
For what it is worth, my interest in a new head has nothing to do with weight savings and everthing to do with updating the combustion chamber design, port design, valve sizes, and possibly changing to an OHC setup and/or having fuel injector ports in the head. My opinion, based on my limited grasp of foundry and manufacturing processes, is that CNC machining a billet to make a two piece head would be the most economical way to do this. But I freely admit I have very little knowledge of even the basics of machining and metal forging. |
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