what every boy needs - yeah seriously

On Jan 8, 10:30*pm, "Maxwell" #$$9#@%%%.^^^ wrote:
wrote in message

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On Jan 8, 3:56 pm, Monk wrote:

A Subaru?

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First off, we can forget about lost-foam or anything more exotic than
green-sand, simply because there aren't enough of us. *So we stick to
standard, readily available valves, valve guides, valve seats and
studs. *The fins make the castings pretty tricky but if it was easy
you would have seen it years ago.

So we make a L-head and an R-head; mirror images. *We do the best we
can with the fins but recognize our limitations and leave the most
difficult of them as CUT fins: Rather than try to cast perfect fins in
a couple of high-risk areas, we settle for a quarter-inch bar of
aluminum that's configured for easy SAWING, which we do as part of the
flash clean-up.

-R.S.Hoover

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I've alway thought it would be more practical to CNC saw all the cooling
fins. Seems a bit extreme at first glance, but if you go to the time or
expense to fabricate patterns to cast the heads, we must be talk about doing
more than just a couple of sets. So the programming cost might well be worth
the cooling efficency of extremely detailed cooling fins.

I disagree, sand casting would be easier than milling from solid
block. Just sculpt your head out of wax cover with sand and pour your
casting. A little grinding here and there and there you have it. OK,
not that simplistic, but you get the gist.

"Monk" wrote in message
...
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I've alway thought it would be more practical to CNC saw all the cooling
fins. Seems a bit extreme at first glance, but if you go to the time or
expense to fabricate patterns to cast the heads, we must be talk about
doing
more than just a couple of sets. So the programming cost might well be
worth
the cooling efficency of extremely detailed cooling fins.

I disagree, sand casting would be easier than milling from solid
block. Just sculpt your head out of wax cover with sand and pour your
casting. A little grinding here and there and there you have it. OK,
not that simplistic, but you get the gist.

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I didn't suggest milling from billet. Just milling the cooling fins. The
overall head with valley for the rockers, combustion chambers, ports, etc.,
should be green sand cast.

It's also not possible to green sand cast over a wax investment. Even if it
were simple enough to sculpt your heads out of wax, which it's not, you
would have to investment cast them.

Sand casting the heads and machining detail not practical with the green
sand or air set process is the only practical method for producing a limited
number of parts. Tooling cost for wax or foam investment casting would be
too prohibitive.

On Jan 8, 11:21*pm, "Maxwell" #$$9#@%%%.^^^ wrote:
"Monk" wrote in message


It's also not possible to green sand cast over a wax investment. Even if it
were simple enough to sculpt your heads out of wax, which it's not, you
would have to investment cast them.

While sand directly over wax isn't practical there are hybrid methods
of lost wax and sand that the hobby casters can do with good results.
As for being simple to sculpt the heads in wax ...........depends on
your definition of simple.


Tooling cost for wax or foam investment casting would be
too prohibitive.

If your thinking conventional production practices you might be right,
but there are home brew methods that while slower work just fine. We
aren't talking GM production numbers or that level of automation.
====================
Leon McAtee