Tadek,
I spoke with Denis Welch some years ago about his heads and other issues.
Originally the Aluminum head was completely redesigned by SC to improve the
breathing. Denis Welch initially used the same casting but has modified it
over the years to improve what he saw were shortcomings in various areas. I
don't know if he is still using the same casting or not, but I assume that
both source the same basic casting from one foundry. I believe that Denis
has a bit more input now than when he first started.
Several years ago I visited with Mark Lambert of Nashville, TN who was
technical adviser for the club at the time. Mark has done the only real
technical evaluation of the aluminum head (The SC version) that I know of
and the results were impressive. According to Mark the original power band
of the engine with the cast iron head was 2,500 to 3,500 rpm. The power
band with the new head (stock H4 carburetors) was increased to 2,200 to
4,200 rpm. Mark also claimed that a 100 set up with the aluminum head and
stock carburetors would outrun a stock car with the LeMans setup as
delivered from the factory, all do to improved breathing in the head. The
LeMans modified cars with the H6 carbs were trying to force more air into an
already restrictive stock head which of course assumes that the iron head
was not modified (ported and polished.)
Even then, according to Mark there was just so much you could do to open up
the original iron unit which is one reason that led to SC's decision design
a new head. And, there is Micheal's quote which I also use, that it's just
a matter of time before an iron head will crack this making the supply of
original heads a diminishing resource.
Cheers,
Curt Arndt
Carlsbad, CA
'55 BN1, '60 AN5 :{) '72 RWA Midget, '06 Cooper S
On Wed, Sep 24, 2008 at 11:41 AM, Bob Spidell <bspidell@comcast.net> wrote:
> re:
> " from SC it has a single piece of steel inserted into the head with two
> valve seats cut into it"
>
> Is that what's known as "figure eight" valve seats?
>
>
> Bob
>
> --
> ***************************************************************
> Bob Spidell San Jose, CA bspidell@comcast.net
> '67 Austin-Healey 3000 '56 Austin-Healey 100M
> ***************************************************************
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