[Healeys] 100S modifications (was Distributor cap orientation-details)

Patrick and Caroline Quinn p_cquinn at tpg.com.au
Mon Oct 17 23:22:53 MDT 2011


G'day Gary

Let's just say that both engines had the same forebears.

Had to call Steve Pike who confirmed my memory of the differences. The
engine blocks for 100 and the 100S were two separate castings and quite
dissimilar.

However Steve says that it is possible to convert a 100 block into a 100S
replica, but it takes about 30 hours of machining by someone who knows what
they are doing. They do of course have very different cylinder heads.

For instance the head stud configuration is different with the studs on the
100S being of a triangular pattern around each cylinder. So the answer is to
machine plugs to be inserted into the 100 stud holes and drill/machine new
ones in the 100S pattern. There are a myriad of other differences such as
the generator is mounted on the opposite side.

As to the distributor, yes it exits the engine on the opposite side. Both
the distributor and tach drive exit the engine from the same place as the
tach drive exits the 100 block. Both are connected to a common shaft that is
driven off the oil pump. Not too unlike the six-cylinder arrangement. 

To think that I said no to buying a 100S in 1975 when the asking price was
$3,500.

Hoo Roo

Patrick Quinn
Sydney, Australia

-----Original Message-----
From: healeys-bounces at autox.team.net [mailto:healeys-bounces at autox.team.net]
On Behalf Of warthodson at aol.com
Sent: Tuesday, 18 October 2011 12:34 PM
To: austin.healey at gmail.com
Cc: healeys at autox.team.net
Subject: Re: [Healeys] 100S modifications (was Distributor cap
orientation-details)

Mike's article is very interesting, but I am not sure it answers my original
question. Let me restate it. It is my understanding that the 100S engine
used
a 100 engine block. Was the 100S engine based on using use a 100 engine
block
casting (before it had been machined) and then machining it to 100S
specifications or was it based on using an already machine 100 engine block
&
modifying it where necesssary? Also, how did they move the distributor from
one side to the other side? I cannot picture how the distrbutor would be
mounted on the side of the block not originally intended for the
distributor.
Also, how was the distributor driven? Finally, based on Mike's article, what
did the factory deal with  moving the head studs for the 100S engine?
Gary Hodson


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