Jeff Boatright wrote:
>
> Interesting points. I'll gun them down one at a time (just kidding!) The
> point about ignition (detonation is a bad word here) at the optimal moment
> is mute because the pertronix has nothing to do with the _timing_.
It does affect the timing though. The switch is a lot more
precise than the cam-lifting-the-points-open timing.
Most noticeably, old distributors get loose bushings and uneven
points cams. So the timing you set for one cylinder might be off on
other cylinders. As well, the distributor shaft wiggles in it's
bushings as the points ride the cam up to the release point. This
can change the actual moment of opening over the rpm range causing
scatter.
> just a switch, just like the points. The only way I see that the pertronix
> could help here is if the spark is of longer duration.
A good strong solid spark can help timing, because you can assume
that the flame front is ignited right with the sparks first
appearance.
If you have a weak spark, theoretically the spark might sometimes
have to "linger" a bit before it succeeds in starting the flame
front.
Obviously, not a problem when everything is working well,
but anything that helps avoid problems is a good thing.
> OTOH, the change in the wave propagation will
> alter the requirements for timing, so you've probably created another
> problem.
These effects SHOULD cancel out, because you are setting the
timing based on the appearance of the spark at the plug end
(where you clip your light on). So whatever changes you make
to the system that affect the spark delivery, you needn't worry
about because you set it to deliver when you want to and
don't really care how it got there or where you twist
the distributor when setting it.
--
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
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