Ignition Only

[Buchholz, Steven]

... this thread seems to be a bit slow, so I thought I might toss a bit more
fuel on the fire ... ;-)

So far it seems that one of the arguments being made against the wasted
spark system is that it does cause a spark in the "inactive" cylinder.  I
have heard a similar argument about dizzys though ... and that is that to
allow for the range in advance the contact area between the tip of the rotor
and the peripheral post is necessarily the width of the range of timing.  As
the rotor spins it is adjacent to the firing cylinder's adjoining neighbors
in the firing sequence.  I have heard that it is possible for problems to
arise when the spark jumps to an adjacent cylinder.  It seems to me that
jumping to the cylinder that just fired is not too likely to cause problems,
but the next in line is probably on its way up to TDC-compression, nicht
wahr?  It seems to me that this is a much more disconcerting problem, and
would be more likely to occur as the number of cylinders increase.  

As far as the concerns about misfires on the wasted spark system, the
immediate response that comes to me is the fact that motorcycles have been
using this technique for decades.  Motorcycle engines characteristically
have a relatively high specific power output and are high revving ... I
don't seem to hear much about problems there.  I guess there aren't too many
supercharged MC engines though.  Another interesting data point ... my V8
actually came with a distributor on each bank ... 

I did think the point on the multi-coil CDI was an interesting one ... this
has been a very worthwhile and instructive discussion for me!  Thanks to
all!

Steve Buchholz
San Jose, CA (USA)
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