The compression you ave quoted sure sounds like a lot to me from just head
milling. But, I'd certainly open up around the valves as you will have a
better combustion & flow and therefore probably as good of power at a lower
compression figure. Removing enough m,aterial to make a difference on a
couple of ratios is not likly. I will say though with that engine and the
inlet system I would not be afraid of a higher C.R. Always remember that the
compression ratio is a ratio of vulumes not pressures. So.....the worse the
inlet system the lower the actual pressures. RIGHT?? Be very careful
with the ignition timing in the beginning to make sure you don't detonate
the engine away.
----- Original Message -----
From: Vince De Palma <greenery@gte.net>
To: Friends of Triumph <fot@autox.team.net>
Sent: Monday, December 13, 1999 8:04 PM
Subject: Tech Question for R. Kastner
> I also support publishing Kas's technical advice--and here's a question to
> start on. I am renewing my Mk I Spitfire's (racing) engine with new
rings,
> valves and guides (a little winter freshening) and I noticed that the
head,
> although milled substantially, has not had the recommended Kastner
treatment
> in terms of relieving the area around the intake valves and the exhaust
port
> enlargement. My question is, since by relieving the intake valve area I
am
> reducing the compression ratio by virtue of removing metal from the
> combustion chamber am I gaining more power by the relieving than I lose in
> compression? If I don't re-work the head the compression ratio will be
> either 12:1 or 14:1, depending on which copper gasket I use.
> Vince De Palma
> Chicken Yellow Spitfire Pilot
>
>
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