On Nov 22, 2:13pm, Philip J Ethier wrote:
> > Patrick Krejcik writes:
> > it does happen because the CDI makes a spark with an extremely fast
> > rise time. The inductive coupling of the HT leads just running parallel
> > from the distributor to the plugs is enough to make the spark in one lead
> > generate sparks in the others.
>
> Is this why I have sometimes seen that you want to have your spark plug
> wires cross each other at least once? Pat?
Well, I guess it would be possible to get a few picofarads or picohenries of
coupling by running plug wires parallel for short distances. You wouldn't get
enough energy to fire the plug under compression (~10KV), but at atmospheric
pressure you'd only need a few KV... hmmm, I guess if the timing was such that
the "coupled" cylinder was still on it's intake stroke, the weak spark could
be enough to light off the charge, causing a back-fire through the carb(s).
> "Don't cross the beams!" - Ghostbusters
"I don't think so, Tim." - Al of Home Improvement
Pat Vilbrandt Fluke Corporation Everett, Washington USA
pwv@tc.fluke.COM or: { uunet, uw-beaver, sun, microsoft }!fluke!pwv
|