I have talked extensively with David Anton about the Pearce aluminum
heads. David stated the aluminum heads do not flow as well as a well
prepared cast iron head. David has run the Pearce head on the flow bench
and says the flow machine proves this out. The Midget project engine David
is building for Classic Motorsport magazine was specified by the magazine to
have a Pearce head. The editors of the magazine thought the the Pearce
head was a high performance head right out of the box just as everyone else
assumes. The flow bench does not lie. David says he is going to
build both heads (aluminum and cast iron) so he can show them the performance
difference. Any other questions, you can direct them to David when he
returns from the UK. He told me that you can get a hold of him by his
eMail address, but his own employees are saying that he is not answering
questions from them right now. Maybe he does not have as easy access to a
computer as he thought he would have.
----- Original Message -----
From
To: PilotRob@webtv.net ;pixelsmith@gerardsgarage.com
Cc: Spridgets@autox.team.net ; RobertDuquette@Sympatico.ca
Sent: 8/24/03 11:20:15 PM
Subject: Iron V aluminum heads - was Re:
engine health
All,
If I had the money I would have the aluminum head for the weigh saving
alone
and not just weight saved for its own sake but high up and right over the
front wheels just where you don't want it.
Aluminum runs cooler than iron and like for like can run a higher
compression ratio which is either gas mileage or power. I think
have a whole number
maybe more.
The Aluminum heads are all from Pearce no matter who sells
them. Maybe some
folk buy a bare casting from Pearce and grind it themselves.
The aluminum head has bigger ports from stock, possibly massively bigger
and
I would expect that on a standard engine this is detrimental to performance
but on an engine that has a cam with something like 290/300 duration it
would
pay off. Pearce copied some of the features of the APT iron
modified heads that
they built into their aluminium head.
As far as I know, a modified aluminium head would equal or out peform an
iron
head but as with all these things no-one including Pearce has any flowbench
figures for Aluminium heads.
Note all the above is for the A-series head, for the B-series head the
arguments for the aluminium are weaker.
Also, the above doesn't include comment on the Mini Spares aluminium 8 port
head which may or may not be as good as the Pearce head. And
don't forget the
16 valve aluminum heads from KAD and Jack Knight.
Daniel1312
In a message dated 25/08/03 02:36:39 !!!First Boot!!!,
pixelsmith@gerardsgarage.com
writes:
Hey Cap'n,
I don't know where you get your numbers from to make this claim, but
I have recently heard from an extremely knowledgeable and well known
source that the aluminum head does NOT flow as good as a stock cast
iron head and that if the extra money spent on the aluminum head
invested in even mild porting of a stock head with Rimflow valves
would perform much better. I only recently heard this and was
surprised myself, but the credibility of this individual I think is
without question. If you have some factual data to back up your
claim, I'd like to hear about it.
Gerard
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