[Healeys] Alloy Head
varley at cosmos.net.au
Sat Nov 1 15:02:38 MDT 2014
Hi Guys, all interesting stuff, I absolutely agree if the head is
cracked, it's a boat anchor even though the six cylinder heads out
perform the 100 heads in that regard. I would not throw money at
attempting to repair a Healey iron head. In regards to fitting I prefer
the modern composite head gaskets with steel rings around the combustion
chambers. You can also use a very light smear of gasket sealant along
the spark plug side edge water galleries to prevent weeping from the
galleries close to the edge.
On 2/11/2014 7:51 AM, Curtis Arndt wrote:
> With all due respect, I'm going to totally differ with your statement.
> Some years ago Mark Lambert, Healey restorer in Nashville, TN and
> technical adviser/expert for the club did an extensive evaluation on
> the original Aluminum head developed and sold by SC in England. The
> original cast iron Westlake head is constrained by porting that is too
> small (intake and exhaust ports on the same side) . SC redesigned the
> porting on the head and substantially increased the airflow, almost
> doubling it in the process. This is the standard head SC originally
> developed, and not the upgraded ones that Denis Welch did a few years
> later, using the same basic casting from the same foundry.
> Lambert's testing is essence said that where the old stock engine had
> a power band of 2500 to 3500 RPM, an otherwise stock engine with the
> aluminum head now had an effective power band of 2200 to 4200 RPM,
> effectively double. He also went on to say that a stock 100 with an
> aluminum head would easily out perform a stock modified 100M. And you
> don't need the 1 3/4" H6 carburetors of the 100M/Le Mans. The H4s
> work great since now that you have sufficient airflow, it's the higher
> velocity provided by the smaller diameter 1 1/2" H4s that make it
> perform even better... Basically "Bernoulli 101".
> Plus no cracking issues. I have four 100 engines and 7 heads, and 6
> of those heads are "boat anchors"... Too cracked to repair.
> The another benefit is that since the heads are identical in all
> respects down to the original "Westlake" casting numbers, you won't
> loose any points in Concours.
> So why put good money after bad with a cast iron head that will
> eventually crack, or crack again if repaired (ask me how I know this)
> when you can have superior performance, reliability, and originality,
> all in one package.
> I will try and find what issue this was written up in for anyone
> that's interested.
> Curt Arndt
> AH Concours Registry Chairman
> On Sat, Nov 1, 2014 at 12:44 PM, Larry Varley <varley at cosmos.net.au
> <mailto:varley at cosmos.net.au>> wrote:
> Hi Ray, my personal opinion is that unless there is a problem with
> your iron head don't bother. You probably won't see any noticeable
> performance increase and any small weight saving or improvement in
> heat dissipation really would not be worth the money. The original
> Weslake design works very well, and modifications to the original
> ports and combustion chamber design can easily lead to no
> improvement or worse performance at lower speeds.
> Stay away from Webcon in the UK at this stage as they were making
> an Austin A70 commercial head thinking it was Healey. I don't know
> if they have changed it yet. The A70 commercial head had smaller
> and deeper combustion chambers and with the Healey sized valves
> they were fitting had shocking valve masking. I would not be
> paying extra for a Denis Welch head for a road car, so any
> supplier that can supply a faithful reproduction of the original
> should be ok.
> As a matter of interest "Head Stud Developments" here in Australia
> are also in the process of making a 4 cylinder alloy head, but I
> think they are not quite ready for sale yet.
> Larry Varley
> Nash Healey Lemans Coupe x 2 :)
> I am thinking about an alloy head for my 100. This is a request
> for list wisdom on several issues. I'm thinking "fast road" as I
> have a 3/4 cam. What make / supplier, about what price, what has
> been your experience with one, what else should I be aware of? Are
> there any pros or cons involved here. Thanks Ray Juncal
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