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

[e-wilkins at cox.net]

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

---- Patrick and Caroline Quinn <p_cquinn at tpg.com.au> wrote: 
> 
> Then towards the end of Austin-Healey production Geoff Healey was advocating
> the reuse of the four-cylinder engine in 2.5 litre form with a cross-flow
> cylinder head. (It was still in production in diesel form for the London
> style taxi) In that form it was lighter and delivered a better power to
> weight ratio than the standard BJ8. GCH was a staunch four-cylinder
> supporter, however the powers that be within Leyland were hell bent on the
> Austin-Healey badged MGC, which Donald would not agree with.
> 
> 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 Chris Dimmock
> Sent: Tuesday, 18 October 2011 2:19 AM
> To: warthodson at aol.com
> Cc: healeys at autox.team.net
> Subject: Re: [Healeys] 100S modifications (was Distributor cap
> orientation-details)
> 
> A 100/S block is a completely different animal to a 100 block, as Mike  
> Salter has explained here:
> http://www.acmefluid.com.au/larry/100r/100rengine.html
> 
> 
> Sent from my iPhone
> 
> On 18/10/2011, at 12:30 AM, warthodson at aol.com wrote:
> 
> > Speaking of distributors on the other side of the motor, I  
> > understand that the
> > 100S used a standard 100 block but a different head with the intake  
> > & exhaust
> > on the opposite (RH)side. But I have never read/heard how they moved  
> > the
> > distributor to the opposite (LH) side of the block. Can someone  
> > provide a
> > detailed description the 100S machining modifications that were  
> > required for
> > the conversion? Also, out of curiosity, did anyone ever offer an  
> > aftermarket
> > cross flow head for the 100?
> > Gary Hodson
> _______________________________________________
> Healeys at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/e-wilkins@cox.net