Making cylinder heads from aluminum....how to?

[Donnie1126]

Just wondering what type of aluminum is the best to cast cylinder heads with.Also what is the procedure used to make the heads from a mold?Thanks

[Unkl Ian]

Air cooled,water cooled,or solid ?

[SchmidtMotorWorks]

Yes, head are cast in a mold made of bonded sand. The bonded sand is shaped in a mold called a pattern. Your primary goal in making a head is designing and making the patterns.

The first step is coming up with a design layout, then the design should be made in a way that can be efficiently cast. Unfortunatly all the books I can find on designing castings and making patterns were written for too basic of parts to be helpful in designing a head casting. You will need to become familiar with the concept of mold draft (taper) and how it relates to the shapes you can mold, then look at some existing castings with that in mind and you will see why many things are designed the way they are.

I will be using CAD CAM but keep in mind all the cool castings made before the 80s were made by wood working methods, saws, chisels files etc. If you find yourself getting discouraged at some point look at a Miller or Offenhauser engine. They were made in shops that I would make an anvil in today. I saw a phot of the famous Leo Goosen drafting room at the Drake plant on Gage; it was an old door on some saw horses. The point is anyone can do this that trys hard enough.

I am about to make a set of patterns for a head and block in December. I will try to post the process step by step as I go along so you all can see the key points.

The forst step in the design is collecting all the dimensions for the parts it will fit, first that means the head bolt positions, and on and on.

Don't worry about the casting of the metal, that part will be done at a foundry.

At this moment I am trying to decide what valve port configuration to do. In my few moments of sanity I think I should just scale-up a Gen 1 SBC and minimize the complexity this way anyone that wants a set of castings could put it together with parts from Jegs except the cam and crank. The current design in progress is a canted valve design sort of like a 429 Ford.

Let me know if you have other questions

[Ape]

hi there,

there are two very good books on the subject, but very unfortunately in german by ludwig apfelbeck who was basically the prime force behind the radial 4 valve (radial-diametral) F1- bmw engine of the 60´s. He did very much research and PROTOTXPE work for rotax and KTM and thats what both books are mostly about. He goes from a practical standpoint into pretty much detail of how to built a prototype engine (casting angles, alloys etc.)
If having to translate isnt anything that makes you feel discomfortable with, both of his books can be very recommend.

Also a trades book for die and tollmaker might be helpfull, since for casting alloy contents are very important.

regards

[phoenix]

Is it easier to design and cast a cylinder head with roughed in ports and chambers, like Pro Stock and Nascar, or a "take out of the box and run" piece? Also, designing efficient water passeges seems like an art in it self! How hard is the process? Are all heat treats created equal? CFE's website claims "Few manufacturers know how to do it right." And becuase they do, their heads "have 3 times the life!" Porosity is another area of concern. Anybody with high dollar heads wants a good return investment, both in part durability and on the track! Thats why manufacturers like Dart and Blue Thunder stand the test of time. Alot of us have good idea's we would love to see come to life, guess the unknowns can get a little creepy , especially when its your dough!

[SchmidtMotorWorks]

Is it easier to design and cast a cylinder head with roughed in ports and chambers, like Pro Stock and Nascar, or a "take out of the box and run" piece? Also, designing efficient water passeges seems like an art in it self! How hard is the process?

It is much easier to design a roughed in casting than a detailed one.

Water jackets are mostly formed by the shape of the head, ports and their wall thickness. Then you can add structures to make the deck more rigid and divert water flow if needed. It is also important to make sure there are no extra big cross sections in the water jacket. The reason is that water needs to move fast to cool effectively. Water that is not moving has even less thermal conductivity than aluminum.

As for casting quality, a very large percentage of all aftermarket performance cast heads made in the USA are cast in one foundry here in California.

[phoenix]

Do large cross sections develop steam pockets? Would that foundry be Buddy Bar?

[SchmidtMotorWorks]

From what I have read, steam pockets develop where the water jacket has volunmes higher than an escape route for air to escape and where the water is stagnant (not moving enough).

Yes the foundry is BB but for those of you that are just thinking about making your first casting, please don't call them with beginning questions about making castings, 99% of the questions you will have are better answered by a pattern maker and BB doesn't make patterns. The time in the process to go to the foundry is when you have a pattern already designed (or made) and then the foundry will tell you how they want the runners and gates made. (this is the passages that the metal flows into the part through).

I have recieved several emails latelty from people wanting to make castings. One had a good idea for a first project, a valve cover. If there is interest, I'll post the steps to doing that. let me know though becuase it takes a lot of time and I'm rushing to get the V12 patterns going now.

[Grocerius Maximus]

From our limited and brief experiences with getting simple sand mold aluminum castings and some fairly complex stainless investment castings made, shrinkage compensation seems to be more art and trial and error than science.

[Donnie1126]

Thanks for the replies and the help.I've been interested for a long time in making an aftermarket head for bb Chryslers based on the regular production head and the Max Wedge design.One of my main interest is to keep a stock appearing look to the outside of the head which I think would be in the interest of alot of people that want to retain a somewhat stock look for their engines.At the same time I would like to make the heads real performers and therefore competitive.I really haven't much idea about what it takes but I do have a few ideas on the internal design.Is this something that can be done in the backyard or do I really need a foundry to do the work?I'm not rich so I figured I might give it a try and see how it goes if it's within reason.That is to actually make the molds and pour them myself.That's why i'm asking here what ya'll think.I realize I'll need someone to machine the rough castings.Thanks again for any help.

[SchmidtMotorWorks]

Donie,

Yes you can make a set of patterns to make a small number of heads with wood shop methods. The castings will be expensive though, at least $350 per casting plus machining.

You can reduce that by almost half with production tooling which means metal molds for the sand. For a conventional cylinderhead a good set of metal patterns will cost $20K (at the very least).

It is extremely difficult to make mony in casting heads and manifolds.

If you just want the pleasure of making a head, you can do it with wood working tools.

If you want to make money, invest in real estate and stay away from automotive castings.

[jsgarage]

To answer your first question, some or most early production & aftermarket heads were cast in A-356 alloy and heat-treated to 'some nominal level' after casting. I have some rear suspension hubs cast of remelted 6061 that are heat treated to a bit more strength. After you cut up a few heads to study water jacketing design, you'll get an appreciation for the tech that goes into cylinder heads. A couple of night school courses in metallurgy should be considered. Or a temp job at a metal foundry.

Don't be discouraged by failures. Dan Gurney and Phil Remington- two of the smartest, most innovative guys ever in this field, designed some special racing alloy heads in the '80s that were failures due to flexible combustion chambers that eventually caused cracking. That's another reason to not have (relatively) large open spaces in water jackets. Their next series of heads didn't crack.

Another example: '70 closed chamber 351-Cs in cast iron worked fine on the street and in drag racing.... until NASCAR got ahold of them. Hours of full-load full-throttle run time at 7500 rpms showed some of the iron combustion chambers flexed enough to reverse the cooling water flow in the heads, causing overheating! So have a good idea how you'll be using your creation(s) and design accordingly. Personally, I'd suggest starting with a Miata cylinder head to reduce the number of parts you need and with a ready market for your success. Good luck and keep posting your progress!

[Chris_Hamilton]

@jsgarage You do realize the last post in this thread was 16 years ago?

[JohnP]

Bill Kuran did a one-off casting for his Willys. The mold was made with 3D printed sand:

https://www.oldwillysforum.com/forum/in ... 42/page-29

[panic]

Who has a larger budget, manufacturing capability, name recognition, and customer base: you, or Edelbrock?
Trust me, if it's not already being done there is either
1. no market for it
2. no return on investment
3. both