who knows in detail the process of casting a cylinder head?

Thanks Rob to get better on the computer I need to spend less of my spare time working on my cars and more time on my computer and I dont think im prepared to do that Only on here today because its raining and my garage is full of cars so i have to do my car work outside at the moment

 

Cadillac flatheads didn't!

 

but is extremely unlikely to find one in Uruguay. I might have more luck with Flathead sixes.

Besides, inline sixes are smooth and when revving high, they sound like ear porn.

 

Go to youtube and search casting aluminum, or steel, or iron... Also search sand mold casting, lost foam casting, and lost wax casting. Lots of good info there.

 

Now I know, thank you.

 

http://www.dmdaustralia.com.au/block.html

Good article on a block ( not a head) but same techniques apply.

Also

http://www.backyardmetalcasting.com/

go nutz!

 

Watch these films,

http://www.archive.org/details/MasterHa1936

http://www.archive.org/details/MasterHa1936_2

http://www.archive.org/details/MasterHa1936_3

http://www.archive.org/details/MasterHa1936_4

The first two sections about sand casting a block and the work involved.

Joe

 

Wow! those are cool films!

 

On National Geographic's "Ultimate Factories" They toured and filmed the Ferrari Factory. About half way through this video http://www.youtube.com/watch?v=dOjtIZ3Vsnc There's some excellent footage of them creating the molds, cores and castings for the heads and blocks....It's an OT car, but the process is fairly impressive!

 

I beg your pardon sir!
My grandfather and father were not anal and you owe them an apoligy.

 

I took it as a good thing,a compliment- as in very meticulous!

Did you read the whole statement, in context? He called them "Highly skilled",and stated "Very few individuals on the planet are capable of this work".

I think maybe you should not be so thin-skinned.

 

thx flattie, yes i do work for a foundry, but we have never messed with casting pistons yet, we do see it in the future though.

www.PhillipsPatterns.com

I can help you and answer any questions you have on how to do it though, i have personally poured green sand, air set, shell core, permanent and ran die-cast machines since i was 15 years old. I've prepped, gated, cored patterns, molded, squeezed, knocked out air-set, green sand, and shell core, iv CAD designed parts, then reworked the parts to be usable in molds. My family has been in the foundry business since 1947 started by my grandfather.

Creating a pattern for molding is no easy task, u cant just take what you want and mold it in some sand and get the same part. there is a lot of factors the go into the equation like metal shrink 1/8 for every square foot for old school pattern makers but i like to just use a 1.25% shrink on metal from the pattern. U also have to design the pattern with Draft, u can not, even if you are the best molder in the world, safely pull a pattern out of a mold with 90° walls or edges, ull knock sand into the mold and create a lot of porosity. U also have to design it with the gating which takes a lot of skill to do right. U have to fillet edges so they pull easy, placement of the down screw will dictate heating and cooling of the metal, the metal you use will affect shrink and if you need to heat treat it before CNC. Molding in the cope or drag will change the part drastically. You will need to have the an 1/8 thicker surface on the pattern for any surface you plan on machining. For coring something small like a piston it become even more complicated because bellow 1/2" in size, it can become very difficult to knock out. you will also have to design the pattern very different if you make on coring it.

If you have any questions feel free to PM me and i can answer any of them. I can also help you in the design if needed, if you have a CAD file of the part i might even be able to cast a sample for you.

 

I see
But I dont understand one part: the final piece will always be 98,75% in size compared to the master pattern?

 

Very cool thread. Please keep the information coming.

 

Writing a term paper? Interesting topic, though.

 

I most certainly will not apologize to your Father or your Grandfather, much respect was shown to the guys in the mold and pattern shop in my post that you are referring to.

However I will offer my condolences to them both for your obvious lack of reading compression, and your ....awe never mind. You wouldn't understand THIS EITHER even if you did actually read it.

 

What you are missing, is the pattern has to be made larger then the final piece, to allow for shrinkage of the metal as it cools. If the head is made out of aluminum, the pattern is 3% larger then the final piece. To make a cylinder head, you need a pattern for each of the 6 sides, corebox's for each port design/runner, then corebox for the water jacket, or multi corebox's for the water jacket, runners, riser's, and a few other things to think about. Melting the metal is the easy part.
Just my 2c

 

When you heat any substance the molecules will begin to become excited, causing them to expand apart from each other, when you take aluminum ingot and heat it from room temperature to 1250°(usual die-cast temp)-1450°(greensand/airset/permanent) the metal will expand a lot. So, when you pour it into a mold and it cools back down to room temp it will shrink roughly 1.25-4%. Heat, type of metal used, casting size, risers and feeders and mold material all affect the % shrink. If you talk to most old pattern makers or foundry guys and say X.XX% shrink they will look at you like a idiot, most just go by 1/8" shrink for every 1sqft of material.

Some extra into metal shrink is that as the metal cools in the mold, it cools unevenly, when this happens, the colder spots on the casting will pull metal from the hot spots and vis versa, this causes weak spots in the casting. To compensate for this we use risers, feeders, tabs, and design the gating to help. Risers and feeders are are basically big tubes designed into the mold so when the part cools it will pull metal from the hot tubes instead of the part, gravity also plays a small part. tabs are just small pockets usually an 1"x1/2" long pockets attached to the part at the parting line, mostly used in die-cast molds.

 

I suspected that, the temperature it's on Celsius or Fahrenheit.

 

Fahrenheit, aluminum has a metaling point of 1220-1400 depending on the metal. it will boil at 4560°F. For cast aluminum pistons, most high performance pistons are Hypereutectic aluminum alloy. hypereutectic alloys are metals that have a higher than normal silicon content, the more silicon a metal has the more resistant it will be to thermal expansion. I was researching these metals when i was looking into possible overhead rotary valves for a v8.

Two of the most common hypereutectic aluminum alloys are 4032 which has a silicon content of 11-13% and 2618 which has a silicon content of around 25%, but the higher up an alloy goes in silicon content the stronger it will become but more brittle it will become. 4032 will metal at 1000°F but heat treating can change this but not by much. When ever you see a metal with a -T3,-T4,-T6 at the end that is means it has gone through a heat treat process, certain metals require a heat treat before they can be machined. When ever we pour A356 we have to send it to heat treat for T6 which is a 2 phase treatment. If we don't the metal will shear off kind of like gum, leaving a rough surface.

 

One more thing about heat treating. when you use shell/air-set core in a part, if you send it to heat treat the core be baked out of the casting, that way you don't have to use a knock machine.

We plan on making some videos of our foundry of how a part is made from complete start to finish, starting at drawing it on CAD. Hopefully we get them done sometime this summer.

 

OT: Any luck with the rotary valves? since i discovered them I ways wanted a Coates style set.

I know Dunstan pulled it off in the 50's and coates managed to make some gas industrial engines, They are pretty silent for the size

 

Thanks for posting these Joe H. Super interesting and a pleasure to watch.

 

They are pretty cool, sure a lot of 216 engines going by! And how about they guy adjusting them while running or spinning using a pry bar against his ear.

Joe

 

i haven't done anything on them, i was just researching potential high thermal resistant metals that could be used in them. Coats is the only company iv found that has tried to make them but for such a major technological advanced valve design i can't find any videos, reviews, prices or even anyone saying they've seen one.

 

http://www.youtube.com/watch?v=20R9nItDmPY
supermegacool as long it's as strong or stronger than traditional casting

 

Ford's modular V8, including the amazing new Coyote 5.0 [drool!] uses powdered metal connecting rods... Tho in all fairness and honesty, I know nothing about powdered metal, so the rods could be made out of an entirely different kind of metal, or a different process.
Food for thought tho...

 

We use this 3D printer for printing prototype parts and making green sand/airset patterns, its saves us a lot of time and money making patterns. Jay Leno actually uses this exact printer in his garage for when he can't find a vintage part that are not produced anymore.

http://www.youtube.com/watch?v=bL0faK3FM4o

 

this isn't about cylinder heads but this is the exact process of what we would go through in creating a cylinder head here at our foundry. This is a short article i wrote of how we produced a 6-71 blower front gear cover, i don't go into much detail but i plan on making some videos that show exactly how we do it.

http://www.diamondp.com/kb_results.asp?ID=3