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

[Blue Healey]

Hey Wilko
I thought I had seen all the content on Larry's site and then you come up
with that excellent page.  I have searched the Larry's home page again and
still can't find the link.

Thanks for sharing.
 _____________________________________________
(______________ Alan Bromfield _______________)
      (______ \____1957-BN4____/ _______)
          (_________________________)
         http://tinyurl.com/healeyforum


-----Original Message-----
From: healeys-bounces at autox.team.net [mailto:healeys-bounces at autox.team.net]
On Behalf Of e-wilkins at cox.net
Sent: 18 October 2011 18:33
Cc: healeys at autox.team.net
Subject: Re: [Healeys] 100S modifications (was Distributor cap
orientation-details)

In the early 90s Geoffrey built a high rev engine from that 2.5 litre
deisel:

"The Austin diesel engine has a bullet-proof block and crankshaft to
withstand the 22:1 compression ratio necessary to run a compression ignition
engine and therefore overcome the inherent weakness of the original A90
petrol engine. Both Dave Jeffery of SC Austin Healey Parts and John Chatham
were keen to see if Geoff's original proposals could be made to work. Design
and development started seriously at the beginning of 1990.
It was decided to retain the shorter stroke of the diesel engine (101.5 mm
compared to 111mm for the A90) in order to allow a higher revving engine and
to avoid alterations to the substantial crankshaft. This is a nitrided EN40B
forging with larger bearing sizes than the original. The block was over
bored into the water passages, and then linered using specially made thick
wall liners. These were then bored to virtually 91 mm for a capacity of
2615cc ( compared with 2670cc originally ). Ford Sierra Cosworth pistons
were used and new con rods specially made ( the diesel rods being much too
heavy for a high revving engine).
The top of the diesel block has a multitude of studs, non of which lined up
with the holes for the petrol cylinder head. Two studs were very close and
one of SC's new 100/4 alloy heads was machined specially to suit these. The
rest of the studs in the block face were blanked off and the remainder of
the studs required to fit the head specially drilled. All of the studs were
specially made in EN24 heat treated to 80 tons to enable torquing up to 125
lb ft. Because of the engine family resemblance, the pushrod holes and
combustion chambers lined up well enough."

The whole article is here at Larry Varley's awesome website:
http://www.acmefluid.com.au/larry/chatham.html
Wilko