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Re: [Fot] Distributor centrifugal advance curve for race engine

To: fot@autox.team.net
Subject: Re: [Fot] Distributor centrifugal advance curve for race engine
From: Tony Drews via Fot <fot@autox.team.net>
Date: Fri, 19 Mar 2021 17:53:55 -0500
Delivered-to: mharc@autox.team.net
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When I had crank fire ignition I did test it on the dyno and found that 
a slight retard as RPM's went up helped (at least that's how I remember 
it - up to 34 / 35 at 3000 rpm but down to 32 at 6000).  But with my 
more vintage points system, the advance is "all in" at 3000 rpm.  I just 
set to 30 degrees or 32 degrees or if I'm feeling particularly lucky / 
brave / stupid 34 degrees at max.  Whatever it ends up at low rpm is 
where it ends up.  When racing I'm never under 3000 RPM anyway.

Regards, Tony

On 3/19/2021 5:27 PM, timmmurphh--- via Fot wrote:
>
> What advance curve are folks using in their race engines? I have 87mm 
> pistons, a Kastner G3 cam and about a 12:1 compression ratio. I am 
> using about 19 degrees advance at idle (no centrifugal advance) and 30 
> degrees advance at 3000 RPM.  I don?t know what I have at higher RPM?s 
> because I never looked. I?m currently doing an engine rebuild so I 
> will have to look what I?ve got at the higher RPM?s when I get the 
> engine running. I?m curious as to what others are using and if anyone 
> has done any testing on a dyno with different advance curves.
>
> Thanks in advance for your input.
>
> Tim Murphy
>
> #317 BRG TR4
>
>
> _______________________________________________
> fot@autox.team.net
>
> http://www.fot-racing.com
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    <p>When I had crank fire ignition I did test it on the dyno and
      found that a slight retard as RPM's went up helped (at least
      that's how I remember it - up to 34 / 35 at 3000 rpm but down to
      32 at 6000).  But with my more vintage points system, the advance
      is "all in" at 3000 rpm.  I just set to 30 degrees or 32 degrees
      or if I'm feeling particularly lucky / brave / stupid 34 degrees
      at max.  Whatever it ends up at low rpm is where it ends up.  When
      racing I'm never under 3000 RPM anyway.</p>
    <p>Regards, Tony<br>
    </p>
    <div class="moz-cite-prefix">On 3/19/2021 5:27 PM, timmmurphh--- via
      Fot wrote:<br>
    </div>
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      <div class="WordSection1">
        <p class="MsoNormal">What advance curve are folks using in their
          race engines? I have 87mm pistons, a Kastner G3 cam and about
          a 12:1 compression ratio. I am using about 19 degrees advance
          at idle (no centrifugal advance) and 30 degrees advance at
          3000 RPM.  I don?t know what I have at higher RPM?s because I
          never looked. I?m currently doing an engine rebuild so I will
          have to look what I?ve got at the higher RPM?s when I get the
          engine running. I?m curious as to what others are using and if
          anyone has done any testing on a dyno with different advance
          curves.<o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal">Thanks in advance for your input.<o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal">Tim Murphy<o:p></o:p></p>
        <p class="MsoNormal">#317 BRG TR4<o:p></o:p></p>
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      <pre class="moz-quote-pre" 
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