IF Anybody cares? IF ANYBODY CARES! Hey, I'm a
died in the wool flathead and hemi guy. Lets
hear more. (My wife said the flat head is very
evident on top of my shoulders, and the hemi is
very visible under my belt!)
--- ardunbill@webtv.net wrote:
> Hi Rich and Folks. Glad to see some interest
> in my favorite subject.
>
> It is not easy to get your hands on Facts about
> the original Ardun
> heads. There is a large body of mythology
> along with the facts. Period
> journalism has errors. Misprints abound.
>
> Looking at the original company literature, it
> states the head castings
> are Alcoa 355-T6. OK, thinks I, this is merely
> a misprint for the
> well-known 356-T6. But no! Machinery's
> Handbook gives 355 as a common
> casting alloy, along with 356, and very little
> difference between them.
> So let us say that the original literature is
> correct, and accept the
> castings as Alcoa 355-T6. The T6 means a
> certain heat treatment applied
> (details known to experts) but I do know it
> makes the castings harder,
> tougher and stronger, all good.
>
> Today's repros are said to be cast of Alcoa
> 356-T6. Probably some
> slight difference, have we any experts out
> there who can tell us what
> the practical difference is?
>
> The cartridge fire principle where the spark
> plug electrodes are up in a
> little hole about 3/8" from the combustion
> chamber has always been
> intriguing. Several Ardun greats have told me
> that this has no effect
> on power (most of the older records were set
> with cartridge fire
> heads), just requires more spark lead because
> the ignition is slowed
> down. Clem TeBow recently told me at C.T.
> Automotive they found on the
> dyno that with a Vertex mag, power was the same
> from 40 degrees to 50
> degrees advance, so they selected 45 as a
> conservative figure. Every
> combination is different, so your results may
> vary. When the cartridge
> fire is deleted, as with today's repros, you
> use about 36 degrees total
> advance, depending on fuel, engine size,
> compression ratio, etc.
>
> The original Ardun heads are heavy and strong,
> and the general lore is
> that they have survived 50 years very well, not
> very prone to cracks or
> serious corrosion. Obviously there are a lot
> of them still around.
> Zora told me about 300 sets were made. I
> imagine probably at least 200
> of them are still with us, maybe more. Not
> something you throw out
> readily.
>
> Speedy Bill at Speedway has an Ardun repro
> project which has not yet
> been completed. He told me that Arduns on
> nitro are prone to cracking
> in the top of the chamber. If he meant
> something like 90% at
> Bonneville, I wouldn't fault the heads or the
> designer for that, it is
> far beyond the original design intentions.
> Ardun experts have told me
> that if any cracks did arise from any cause,
> they cured them by expert
> welding and remachining.
>
> What connection did Ardun and the Hemi Chrysler
> have?? Stay tuned (if
> anybody cares) for more documented speculation.
> Regards, ArdunBill in
> Chesapeake, VA.
>
>
=====
Dick J in East Texas
- - ECTA #72 - -
G/FCC - FX/STR
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