Let's not forget that usually aluminum (or even just aluminum heads) engines
can tolerate more compression.
My '63 Buick 215 is one of the 11:1 CR versions. While I'm sure that the CR
is not quite what the factory advertised, but it's still higher than this
3.9 that I am looking for pistons for. I have just a hint of pinging under
load running on mid-grade fuel.
Carl F.
215 MGB in TN
----- Original Message -----
From: <GrayTesla@aol.com>
To: <longez8@bellsouth.net>; <215v8@yahoogroups.com>;
<mgb-v8@autox.team.net>
Sent: Wednesday, May 12, 2004 8:45 PM
Subject: Re: detonation / preignaition
> I guess I'm at a bit of a loss concerning the discussion of detonation and
> pre-ignition. The two engines with which I have experience are the Buick
and
> Oldsmobile versions of the 215 V8 and neither has been sensitive to the
above
> conditions. The Buick version was build with only 8.5 to 1 compression so
I
> wouldn't expect much problem. The Oldsmobile version, using 41cc (small)
combustion
> chamber heads -- along with Arias Arias Pistons, give about 13.5 to 1 and
> detonation/pre-ignition wasn't a problem. IT IS MY UNDERSTANDING that the
Olds
> head is more forgiving in this regard but that it doesn't flow quite as
well as
> the Buick head.
>
> The highest octane available in my area (higher altitude of 4,000 feet) is
91
> on the R+M/2 scale. Initial timing was set at 10 degrees initial and only
> needed to be pulled back to 4 or 5 degrees initial when at sea level --
even with
> coastal octane of 92/93 octane.
>
> Are others having problem with detonation? I never have.
>
> Darius
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