Subject: Re: [Healeys] BN1 Head

From: "Patrick & Caroline Quinn" <[email-masked]>
Date: Mon, 8 Jul 2013 10:29:54 +1000

G'day

The cylinder head for the Austin A90 is different to that of the 100. So is
the cylinder block.

The 100 combustion chambers are far smaller and along with altered ports
provide an improved gas flow, plus the thermostat housing is much bigger in
the 100.

Whether the A90 design was returned to Harry Weslake Engineering or not
prior to casting is not known, but I would be surprised if it wasn't.

Hoo Roo

Patrick Quinn
Blue Mountains, Australia

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of Simon Griffin
Sent: Monday, 8 July 2013 10:12 AM
To: [email-masked]
Subject: [Healeys] BN1 Head

I have been reading Bill Piggott's book about the 100 and of course there
are several references to Westlake being contracted to design the head for
the 100M.  However, is it not fair to say that Westlake designed the stock
cast iron head on the BN1?  Or I suppose if being honest he desinged it for
the A90, not the AH.  Poking around and photographing everything today, I
note a Westlake patent number cast into the head just in front of the #1
spark plug.

Simon
Troy, Il
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From: Simon Griffin <[email-masked]>
Date: Sun, 7 Jul 2013 21:00:04 -0500

Thanks Patrick.  From reading the book and other written sources I had the
distinct impression that the engine for the BN1 was exactly the same as the
A90, and that was one of the motivations for Leonard Lord to get rid of the
over supply of these engines?  What had prompted the posting in the first
place was the Westlake patent casting on the head of my car.  I had Googled
some A90 engine shots and it looks exactly the same as my car.

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> To: [email-masked]; [email-masked]
> Subject: RE: [Healeys] BN1 Head
> Date: Mon, 8 Jul 2013 10:29:54 +1000
>
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From: "Patrick & Caroline Quinn" <[email-masked]>
Date: Mon, 8 Jul 2013 12:34:01 +1000

G'day

Yes that's true. Austin had massively overestimated the success of the A90
in the US. In fact when you look at the export figures far more Austin A90
Atlantics came to Australia than any other country.

No doubt the first Healey 100 had an A90 engine, but the engine in the
production 100 was slightly different. Put an A90 engine next to a 100
engine and it's easy to see that at the bottom of the A90 head there is more
metal (vertical part of the casting) due to the larger combustion chambers.
Then look at the thermostat housing and you will see that it is smaller in
the A90 and the A70 (2.2 litre version of the engine). The Weslake patent
mark is on them both.

One of the differences with the block is that in the A90 there is just a
single bolt to hold the distributor in place while there are two in the 100.
However I suspect that when BMC issued a replacement block they sent out an
A90 which would explains the number of 100s running around with A90 engines
in them.

Many years ago I used an A70 engine in the 100 I had at the time. A lot less
power and it would start to valve bounce in top overdrive at around 80mph.

Hoo Roo

Patrick Quinn

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of Simon Griffin
Sent: Monday, 8 July 2013 12:00 PM
To: [email-masked]
Subject: Re: [Healeys] BN1 Head

> The cylinder head for the Austin A90 is different to that of the 100. 
> So is the cylinder block.
>
> The 100 combustion chambers are far smaller and along with altered 
> ports provide an improved gas flow, plus the thermostat housing is 
> much bigger in the 100.
>
> Whether the A90 design was returned to Harry Weslake Engineering or 
> not prior to casting is not known, but I would be surprised if it wasn't.
>
> Hoo Roo
>
> Patrick Quinn
> I have been reading Bill Piggott's book about the 100 and of course 
> there are several references to Westlake being contracted to design 
> the head for the 100M.  However, is it not fair to say that Westlake 
> designed the stock cast iron head on the BN1?  Or I suppose if being 
> honest he desinged it for the A90, not the AH.  Poking around and 
> photographing everything today, I note a Westlake patent number cast 
> into the head just in front of the #1 spark plug.
>
> Simon
> Troy, Il
$12.75

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---

From: "Patrick & Caroline Quinn" <[email-masked]>
Date: Mon, 8 Jul 2013 17:48:58 +1000

Hello Again

It appears that I am mistaking the Austin A90 cylinder head with that fitted
to the A70.

That font of all things Austin, John Harper tells me that the heads for the
100 and A90 were the same, but in earlier A90 applications the rocker
pedestals were taller which was accompanied with a taller rocker cover. Only
the 100 heads were fitted with double valve springs while the A90 were not.

John kindly advised that the A90 cylinder blocks were different, but as
mentioned only as to the distributor fixing.

Hoo Roo

Patrick

-----Original Message-----

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From: Joe and Lenore Armour <[email-masked]>
Date: Mon, 08 Jul 2013 18:43:04 +1000

Simon Griffin wrote:

>I have been reading Bill Piggott's book about the 100 and of course there are
>several references to Westlake being contracted to design the head for the
>100M.  However, is it not fair to say that Westlake designed the stock cast
>iron head on the BN1?  Or I suppose if being honest he desinged it for the
>A90, not the AH.  Poking around and photographing everything today, I note a
>Westlake patent number cast into the head just in front of the #1 spark plug.
>
>Simon
>Troy, Il
>______________
>  
>
        Harry Weslake was a proflic engine designer.   He has quite a 
number of patents for head design and combustion chamber details in 
particular.  Re BMC he was responsible for the 'heart' shape of the 
cylinder combustion chamber which gave good swirl to the incoming 
fuel/air     mixture promoting the burn characteristics he considered 
optimum.
    This combustion chamber was applied to a number of BMC cylinder 
heads.  
    Harry was also given credit for the A-Series cross flow semi 
downdraught head used on the late ( 1967 & 68 )  Sebring and LeMans 
Sprites that used Lucas mechanical fuel injection.  Good for 150mph at 
LeMans with a 1293cc engine

    Dan Gurney used him to design his formula one 12 cylinder 
Guerny-Weslake engine

    Harry also was called upon to design a single cylinder speedway bike 
engine.

        Joe

[email-masked]

---

From: John Harper <[email-masked]>
Date: Mon, 8 Jul 2013 11:30:06 +0100

Regarding the Westlake patent. I agree with Joe. It is my understanding
that the patent was sold initially to the Austin Motor Company for their
use of the heart shaped combustion chamber on most if not all overhead
valve engines. I believe that the first was the Austin 16 in December 1945
where immediately after the war the pre war Austin 12 body was given more
power There was no additional patent for use on the 100M.

The Westlake company I believe no longer exists but about twenty years ago
I found an ex employee who would polish and profile a head. He told me of
many 'specials' they were involved in and no doubt this included work on
individual owners' engines.

Best regards

On 8 July 2013 09:43, Joe and Lenore Armour <[email-masked]> wrote:

>> are
> cylinder combustion chamber which gave good swirl to the incoming fuel/air
>     mixture promoting the burn characteristics he considered optimum.
>    This combustion chamber was applied to a number of BMC cylinder heads.
> downdraught head used on the late ( 1967 & 68 )  Sebring and LeMans Sprites
> that used Lucas mechanical fuel injection.  Good for 150mph at LeMans with
> a 1293cc engine
>
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-- 
Best wishes

John Harper

AHC UK 100 Register Secretary
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From: Alan Seigrist <[email-masked]>
Date: Tue, 9 Jul 2013 17:40:00 +0800

As an owner of an A90 and a spare A90 motor, I can confirm that the heads
on the 100 and A90 are identical.  The only real variation was in the early
A90, there was a different rocker & springed pushrod set up meant to
minimize valve clatter.  It was a fairly complex system and they eventually
got rid of it around 1950 for the rocker system used in the 100.  If you're
interested, I have pics of the whole set up in an album here:

http://tinyurl.com/nthg3ea

On Mon, Jul 8, 2013 at 8:12 AM, Simon Griffin <[email-masked]> wrote:

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