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[Healeys] Compression ratio for a fast road 100

Subject: [Healeys] Compression ratio for a fast road 100
From: twillig at ruda.de (Thomas Willig)
Date: Thu, 13 Jan 2011 18:03:28 +0100
References: <4E9D161D2AF9984C94D841B0A0D5A1160E0F41@dw01.ruda.local> <5E79CB12-78D9-438E-96B8-72D3EF6BD635@sbcglobal.net>
First of all thanks for the big number of replys to my question. To
clarify my plans:



I plan to use:



DW Fast road aluminum head with hardened studs and DW competition head
gasket.

100S profile camshaft 228/234 with new lightened followers and vernier
sprocket, block with valve relief pockets

10.5:1 DW pistons turned/dished to give 9.5:1 CR

Harmonic damper on crankshaft

Narrow fan belt conversion

Lightened original flywheel

All components precision balanced

Con rods equalized



Regards





Thomas Willig



Von: David Nock [mailto:healeydoc at sbcglobal.net]
Gesendet: Donnerstag, 13. Januar 2011 17:30
An: Thomas Willig
Cc: healeys at autox.team.net
Betreff: Re: [Healeys] Compression ratio for a fast road 100



Be very careful when raising the compressions on a 100/4. We just
finished re doing a 100 M that had 13:1 flat top pistons in it the
engine would run on and ping so bad on street gas that you could not
drive it. Also due to the high compressions it cracked that crankshaft.



DW only shows a 8.5:1 and 10.5:1.  I would say that with the 10.5:1
option you will have to be very selective on fuel and possibly be
limited to race fuel.



When we are building a performance motor for the street we will use the
8.5:1 pistons with a good performance camshaft, New lightened flywheel
and an aluminium head with hardened studs and special head gasket that
does not LEAK. We also will use a verneer cam gear to adjust the cam
timing to the optimum performance.



We have installed lots of light flywheels on both 4 and 6 cylinder cars.
As low as 15 lbs and had no problems with idle, accleration or any other
of the things that have been mentioned on previous e mails.







David Nock

British Car Specialists

Stockton Ca 95205

209-948-8767



www.britishcarspecialists.com

.

.



On Jan 13, 2011, at 7:23 AM, Thomas Willig wrote:





Hello,







I am in the process of rebuilding the engine of my 100. In order to get

some more punch from it, I am thinking about fitting DW forged pistons

with an 9,5:1 compression ratio.  You all know that if you talk to three

people (all of them not A-H 100 owners) you will get at least four

different opinions. Statements given were:











"You will get detonation at this compression rate"



"You will loose all smoothness of that engine"



" A motor with that CR is only drivable on the track"



"You will have to buy three head gaskets every year"







I am aware that most of this is probably nonsense, but... maybe..??







I guess there must be experienced folks on the list who are running

engines with a 9,5:1 compression ratio. Please come forward and share

your experiences and thoughts with me.







Regards











Thomas Willig

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