I have a little experience with Alum castings. Mostly die cast and Semi
permanent mold, and some with Iron castings.
In aluminum no experience with parts as big as a cylinder block, but having
tested smaller parts ( 4.6L Front cover) that were cast, verses billet, I
found the
mechanical strength of the billet part FAR better than any casting which is
full of air bubbles of various sizes.
Almost regardless of alloy. (I no longer have any data), the density of
the material is so consistent in a billet part, and with stress relieving
and additional heat treat the block will be indestructible. (and very
repairable.)
Besides, they do it because they can.
If you consider this the rapid protyping and very limited production (1 copy
per week or less) I'll bet the cost per piece will beat cast parts including
tooling and the learning process for vents and sprews.
Way back I did a 2.3Liter block for Ford SVO. I was working with and visiting
our engine plant and casting center at Taubate, Brasil on a regular basis.
We modified old water jacket cores, and added lots of iron to the main webs
and skirt, Siamese bores and .750" deck. In all added 26 pounds of Iron.
My point is
The casting/learning process required over 1000 parts to get 200 good usable
blocks. Many times the airbubbles/voids would not show up till almost the
end of the machining process.
I have visited Kirkhams, and looked at their parts. They produce
extraordinary products and I think they are bringing the FE into the present
time. They are using current technology to update the classic powerplant.
I don't think there is much of an economic slump for the folks that can
afford the Kirkham products.
The Billet 427 sure is a perfect engine into their roadster or Daytona
Coupe. Absolutely over the top.
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