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Re: distributors (ignition curves) Jan 2002 09:01:50 -0800

To: John.Deikis@med.va.gov (Deikis, John)
Subject: Re: distributors (ignition curves) Jan 2002 09:01:50 -0800
Date: Sun, 6 Jan 2002 09:15:35 -0500 (EST)
Cc: Midgetracers@aol.com, spridgets@autox.team.net
John-

Not much you need to know, John, that
is not covered in Vizard's book under
ignition mods needed for longer period
camshafts, high compression motors,
those with headers/free flow systems, etc. Of course, these are
generalities.

The "correct" way to go is a dyno session
set up (including the operator!) for performance tuning. Baring this
being
available, you can do a "ballpark" job
with Vizard's suggestions.

All things being equal, a 23D4 Cooper
S type pretty much fits the bill.

Quick low end advance for the longer
duration cam. (22 degrees at 1200 engine
rpm on an adjustable timing gun as run
on stock '67 Sprites equipped with 23D4's).

You will probably have to "tailor" (here is
where the distributor machine comes in
handly) the top end of curve to give you
no more than 28-30 degrees of crankshaft
advance (14-15 distributor degrees minus
the initial advance!) at 6,000 engine rpm
considering the "greater" cylinder filling capabilities of the 276 cam
at the "top end". 

I would think 30 total crankshaft with
CR's up to 9.8-1 and 28 total crankshaft
for higher static CR's on the highest
octane pump fuel available to you
(probably Sunoco 94MON;  about = 
97-98RON+- a bit)

My $0.02!!




Cap'n. Bob
    '61 :{)

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