Actually, the square box Duraspark module has much more in common with
the Pertronix than it does to an MSD or Jacobs multi-spark ignition. The
Duraspark is not a capacitive discharge system, it doesn't use a
high-voltage coil drive to decrease the coil saturation time, and it
only releases a single spark per trigger event. You can use the
Duraspark module with the stock tach wiring and internals - maybe not
all of the original tachs will take it, but the example I've seen worked
just fine.
One note: This link (below) suggests that the Duraspark is powered
through a length of resistance wire. This is the first I've heard of
that, but I haven't researched the Duraspark module very deeply either.
If you are looking to use the Duraspark module then you may want to
really figure out how the factory intended it to be wired.
http://www.therangerstation.com/tech_library/DurasparkII.html
Then again, this link here suggests that the coil only is powered
through the resistance wire and doesn't say anything about the module.
This is more intuitive - the module itself should be able to handle 12
volts, while the coil itself should be wired according to how it's
designed - if it needs a ballast resistor or resistance wire then you
must use one.
http://www.crazyformercurys.com/durasparkii.htm
Best regards,
Theo
Steve Laifman wrote:
>
>
> The square box (Duraspark in Ford lingo) is much like other external
> ignition systems, like the Mallory MSD 6 style capacitive discharge
> system. These add energy to a large capacitor, which stores it, and
> release it in a very large surge through external, or internal voltage
> transformers (coils), creating a huge spark. It has issues with tachs
> of an older vintage, as Theo points out, and has the cure for.
>
> Steve
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