CNC cylinder heads...quick question...

[jonrpick]

May be a stupid question, but oh well...

Do they start out with the basic shapes cut out and the water jacket cast in place, or is that all machined as well?

Meaning, do they start with a solid chunk of material and literally machine the whole thing?

 

[pauly383]

A basic rough casting comes from the foundry , then the machine takes that and does its magic .

There was a piece on TV not long ago showing Edelbrocks being made .

 

[jonrpick]

A basic rough casting comes from the foundry , then the machine takes that and does its magic .

There was a piece on TV not long ago showing Edelbrocks being made .

Hmm... so one couldn't get one without the ports already there then I take it... ?

 

[pauly383]

The ports would come smaller than they need to be due to using same casting for different head part numbers ( and for porters on race teams to do their own ) , and the chambers are barely bigger than the valves .

Its cast mainly for the rough shape and to give it the water jackets .

 

[jonrpick]

The ports would come smaller than they need to be due to using same casting for different head part numbers , and the chambers are barely bigger than the valves .

Its cast mainly for the rough shape and to give it the water jackets .

Eh... that probably wouldn't work then... Was looking for something a bit more unfinished than that.

 

[pauly383]

http://www.morethanjustpower.com/part.asp?id=46&c_id=2

scroll down

 

[4X4HIGH]

What are you wanting to do?

 

[jonrpick]

What are you wanting to do?

CNC a head from scratch, including the arrangement of the ports and valves. Basically make something that doesn't exist, just to experiment.

 

[jonrpick]

I'll add....

I discussed this once with someone else. It would/could be possible to mill the whole thing out of a solid block of aluminum, but the water jackets could be tough.

One idea we came up with was milling them in from the combustion chamber side and sealing it up, then welding in a cover plate. That would all take place before the chambers were milled in, and obviously before final surfacing.

The trick would be keeping the welds at the same stability as the material to be welded, so that heat expansion wouldn't cause sealing problems once the motor warmed up.

 

[4X4HIGH]

You could never make a head that was fully CNC'd (that still has coolant passages). There is water around all the valves and around the spark plug area as well. At one point in time you used to be able to buy raw forgings from the GM dealer and then put guides, ports where ever you wanted. I'm not sure if you can still buy them though. You could also buy crankshafts the same way so you could grind your own stroker crank.

 

[jonrpick]

You could never make a head that was fully CNC'd (that still has coolant passages). There is water around all the valves and around the spark plug area as well. At one point in time you used to be able to buy raw forgings from the GM dealer and then put guides, ports where ever you wanted. I'm not sure if you can still buy them though. You could also buy crankshafts the same way so you could grind your own stroker crank.

Yeah, I thought of that... one solution was to go in from the side and hog it out, then weld up the holes, or use screw-in plugs of some sort (welding would obviously be better).

Edit: option #2, and less desirable, is to find someone that's actually good at casting aluminum, and have a blank made that had the cooling passages ONLY.

 

[89yimmiJ]

I used to work for a company that manufactured and cnc'd heads. You can obtain the rough castings from most manufacturers if you know somebody as they did it all the time from Brodix, AFR, Edelbrock, etc.

They always did a considerable amount welding to the heads to change port shapes, chambers, etc. They heated the heads up in an oven to 450 degrees or so for an hour and then tig'd where needed.

After the heads are done and before assembly most manufacturers send the heads out to a company that basically coats the waterpassages with loctite under pressure to ensure there is no leaks. None of the manufacturers ever tell you that though.

Before they actually cnc'd a head, they ran their programs probably twenty times using a block of wood to ensure that it was right before cutting out of aluminum.

The company actually does make heads out of billet as well, however they weigh much more than a cast iron head, and wear out the tooling at an accellerated rate.

 

[jonrpick]

I used to work for a company that manufactured and cnc'd heads. You can obtain the rough castings from most manufacturers if you know somebody as they did it all the time from Brodix, AFR, Edelbrock, etc.

They always did a considerable amount welding to the heads to change port shapes, chambers, etc. They heated the heads up in an oven to 450 degrees or so for an hour and then tig'd where needed.

After the heads are done and before assembly most manufacturers send the heads out to a company that basically coats the waterpassages with loctite under pressure to ensure there is no leaks. None of the manufacturers ever tell you that though.

Before they actually cnc'd a head, they ran their programs probably twenty times using a block of wood to ensure that it was right before cutting out of aluminum.

The company actually does make heads out of billet as well, however they weigh much more than a cast iron head, and wear out the tooling at an accellerated rate.

But, were the water passages already cast into the billet heads or were they milled out with a really expensive machine?

Good info, BTW...Thanks.

 

[89yimmiJ]

On the billet, we started with a big old solid block. The ports or passages had to either be welded or filled where the tools had to pass through afterwards.

Most stuff was done on a older 4 axis machine, however they did most of the prototype work on 40 year old manual, reliable 3 axis Bridgeports where they could get up close and personal with the work.

Check out araoengineering.com as he does all of this stuff.

 

[jonrpick]

On the billet, we started with a big old solid block. The ports or passages had to either be welded or filled where the tools had to pass through afterwards.

Most stuff was done on a older 4 axis machine, however they did most of the prototype work on 40 year old manual, reliable 3 axis Bridgeports where they could get up close and personal with the work.

Check out araoengineering.com as he does all of this stuff.

Awesome! So my thinking wasn't off when I figured you'd need to go in sideways then weld in patches later.