[Healeys] The AEC960 Healey 3000 Cylinder Head spark plug seat and timing issue

[richard mayor]

Chris - and the rest of the guys. This is the first I have heard of this spark
plug depth issue. This is now on my radar!!  So, I walked around my shop
tonight and checked a couple of engines. The AEC 960 is the casting/part
number on my original 3000 engine (circa 1959). It is also the same casting #
on my BJ8 cylinder head. I looked at one of my 100-6 heads and the casting #
is AEC 721. As far as I know, the only real difference between the 100-6 and
300 heads was the boss where the water temp bulb screwed into - hence a
different casting #. The chamber volume is the same.
I think that  what you have discovered is a factory machining issue. You
should not compare a BN1 and Sprite head with the AEC960. That's apples and
oranges. You need to compare a BJ8 head with an earlier AEC 960 head. Having
said that, I am not about to pull the head off my BJ8 motor to make any
comparisons.
Westlake designs have nothing to do with the spark plug depth. Westlake is
only responsible for the heart shaped designed of the combustion chamber.
I would really like to hear from others on the list that can confirm this
spark plug depth issue, because I am pretty sure that the castings are the
same - just different machining practices. Then again, I could be wrong.


Richard Mayor
BN7L-466  Vintage Racer
Portland, Oregon




> Date: Tue, 5 Oct 2010 18:54:53 +1100
> From: austin.healey at gmail.com
> To: healeys at autox.team.net; shop at justbrits.com;
msalter at precisionsportscar.com; frogeye at porterscustom.com;
bspidell at comcast.net; racarbon at verizon.net
> Subject: [Healeys] The AEC960 Healey 3000 Cylinder Head spark plug seat and
timing issue
>
> Ok Guys - here is the follow up as promised re the spark plug seat issue on
> the AEC960 cylinder head.
>
> I've discussed this on and off for nearly 12 years - we discovered this
> issue when I rebuilt my BJ8 in 1998
>
> Yesterday, I pulled out 3 different westlake design cylinder heads - a
> Sprite; a 100/4; and a 3000 - and using the SAME spark plug - took a few
> pics....
>
> Simply - the spark plugs on "some" 12 port 3000 cylinder heads don't go in
> deep enough compared to any other westlake head design.
>
> Which is just wrong....
>
> Here is my take, with pictures....
> http://www.myaustinhealey.com/aec960-healey-cylinder-head.html
>
> Fire away.....
>
> Chris
> www.myaustinhealey.com
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