[Healeys] External differences of six cylinder engines

Chris Dimmock austin.healey at gmail.com
Sun Jun 6 04:19:20 MDT 2010

Hi Josef,
Happy to be corrected, but I'm not understanding the differences you
I've seen 2 different 12port head castings - as i said, the area
around the thermostat/ temp sensor.
The BJ8 head is different to all the earlier 12 port heads.
The unseen difference is the BJ8 head spark plug seat is too far away
from the combustion chamber, by over 100 thou.
That's why a BJ8 has vastly different ignition timing to any other 3
litre Healey engine.
Look at the ignition specs.
Bj8 heads are different. Not sure of your other 2 points


Sent from my iPhone

On 06/06/2010, at 5:19 PM, <Josef.Eckert at t-systems.com> wrote:

> Chris,
> I need to correct you. There are 3 different 12 port head castings.
> 1 The early one without the "nose" for the late 100/6s
> 2 The one for the Thermo-Choke on early 3000s
> 3 The "nose" one following the Thermo-Choke one on 3000 Mk1 to Mk3.
> Josef Eckert
> Konigswinter/Germany
> -----UrsprC<ngliche Nachricht-----
> Von: healeys-bounces at autox.team.net [mailto:healeys-
> bounces at autox.team.net] Im Auftrag von Chris Dimmock
> Gesendet: Sonntag, 6. Juni 2010 04:17
> An: Derek Job
> Cc: Forum
> Betreff: Re: [Healeys] External differences of six cylinder engines
> The cylinder heads are the giveaway. ;-) The log head is the early
> 100/6 The pre BJ8 12 port head is different to the BJ8 12 port head
> casting
> - different casting number, and a distinct difference around the
> thermostat area - look at the sculpting of the head casting In 3
> litre blocks there are 2 castings. Pre bj8 blocks have the dipstick
> low on the block. BJ8s have a high mounted dipstick Obviously, the
> same general guidelines applies to sedans of the same era. Eg a 1966
> Wolseley has the same block/ head casting as a BJ8. But many sedans
> had the starter motor on the opposite side to a Healey. Ie different
> rear engine plate.
> Chris
> www.myaustinhealey.com
> Sent from my iPhone
> On 05/06/2010, at 10:44 PM, Derek Job <derek.c.job at gmail.com> wrote:
>> Hi guys
>> Are there any external differences between the six cylinder engines
>> that would allow you to identify one as being either
>> an IC  (100-Six, Integral head)
>> or 26 D (100-Six, six port inlet)
>> or 29D (3000)
>> thanks
>> Derek
>> www.healeysix.net
>> _______________

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