[Healeys] cylinder head questions

[warthodson at aol.com]

Chris & Mark,
Thanks for the information. I checked my two 960 heads & they both have the
plugs recessed in the combustion chamber as per Chris' information &
photographs.
If this is a machining mistake it is still a mystery why they never corrected
it. And why the BJ8 is the only model a greater advance.
Gary






-----Original Message-----
From: ardmorebusiness <ardmorebusiness at xtra.co.nz>
To: 'Chris Dimmock' <austin.healey at gmail.com>; warthodson
<warthodson at aol.com>
Cc: healeys <healeys at autox.team.net>
Sent: Tue, Sep 20, 2011 9:03 pm
Subject: RE: [Healeys] cylinder head questions


Chris and Gary,
 also have an original works head.  It too has the AEC 721 number
ast into the top.
s an aside, I was told long ago that the heads were made 'after
ours' when production had stopped for the day. They were apparently
ade from recycled diff. heads that had been melted down.
've not done a side-by-side comparison of the 721 and the 960 or
lue-printed either of them, but I have been told that there is also a
light difference in the squish area in the heads, the 721 being
onsidered the better designed one.
ne of our racers here in NZ actually replaced the 960 on his BJ8 with
he 721.  He reckoned it gave him a marginal improvement in
erformance. I don't know how scientific his analysis was  . . .  that
as back in the 70s.
Cheers
ark Donaldson
uckland. NZ

-----Original Message-----
rom: Chris Dimmock [mailto:austin.healey at gmail.com]
ent: Sunday, 18 September 2011 12:50 p.m.
o: warthodson at aol.com
c: healeys at autox.team.net
ubject: Re: [Healeys] cylinder head questions
Hey Gary,
actory alloy heads are all based on the AEC721 - the original 12 port
head - casting. Even Joe Armors BJ8 based 1965 Sebring car has a
actory alloy head based on the earlier AEC721 casting, not the later
3000 AEC960 casting.
enis Welch wanted his head accepted by the FIA - it had to be a
eplica of the factory alloy head. Hence AEC721
ll the AEC 960 heads i have seen are wrongly machined. See
ttp://www.myaustinhealey.com/aec960-healey-cylinder-head.html
hris

ent from my iPhone
On 18/09/2011, at 1:15 AM, warthodson at aol.com wrote:
> A friend purchased a Healey 6 cylinder head at a swap meet recently.
> It has
 AEC721 cast into it. My BJ8 head has AEC960 cast into it.
 Interestingly, the
 Denis Welch aluminum cylinder head has AEC721 cast into it. How many
> different
 6 cylinder heads were fitted to the big Healeys & what were the
 differences
 between them?  Is there any reason you know for Denis Welch using
 the AEC721
 for the basis of their aluminum head? I did notice that the boss for
> the water
 temperature sensor is much more accessible (I.E. getting a wrench on
> the nut)
 on the AEC721 vs. the AEC960 which raises the question why did the
 factory
 change the design?
 Gary Hodson
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