Ignition only

[J. Creech]

Thanks Bruce, I was hopin' you would set me straight. It seems a little
clearer to me now.

Scott Creech


----- Original Message -----
From: "Bruce Plecan" <nacelp at bright.net>
To: <diy_efi at diy-efi.org>
Sent: Friday, November 10, 2000 10:25 AM
Subject: Re: Ignition only


>
> It's an EE thing.
> The spark is A/C so nothing is backwards
> There is a 50-50 chance on which way the spark lights, and for the first
> .00000000001 usec (time approximate) does it really matter?.
> It's the repeated colapsing on the magnetic fields that generate the
current
> to maintain the firing line on a scope.  Once the ion level between the
two
> electrodes drops, the resistnace goes high the coil condenser oscillations
> decay, then you can easily see the A/C component of the signal, and event
> over, points close signal and the coil starts to saturate again.
>      If you think of the secondary as A/C things make sense rather then
some
> of the other explainations, floatin around....
>
> I have never seen a proper tuned engine show where one side is different
> from the other on DIS plugs,  there are the same differences with dissys
on
> some engines.  Largely do to other things like the coolant by pass lines
> being biased toward on side of the other.  On v series engines there is
> usually one thermostat so one head is always running a tad cooler then
the
> other in this reguard.
>
> Bruce
>    That's how it looks to me,
>
>
>
> I'm having trouble understanding the concept of firing the second plug
> > backwards.
> > After the spark jumps the gap on the first plug, isn't the "path of
least
> > resistance"
> > going to be head-block-chassis instead of trying to jump the airgap of
the
> > second
> > plug?? (compressed or otherwise). I'm probably missing something basic
> here.
> >
> > TIA
> > Rod
> > 944 turbo (+NOS and big Turbo)
> > only 7000 RPM so 1 coil 1msd. (sufficient??)
> >
> >
> >
> >
> > >0ne difference I didn't see mentioned is that waste spark systems
> > >fire one plug "backwards". (Normally the hot center electrode is
> > >negative, since it's electrons being emitted that actually start
> > >things off, as in vaccum tubes.) This probably means that the plug
> > >gap in those cylinders cannot be as large as in a "forward"
> > >cylinder, but I'm not sure if this is a meaningful difference or
> > >not.
> >
> >
>
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