[Ford-ferguson] ignition coil and resistor

Chris Britton c.britton at worldnet.att.net
Fri Aug 13 14:44:13 PDT 2004


The front mount oem ignition coil likes about 3.5 volts.. ford accomplished
this with an inline ballast resistor.  if you are going to use the same oem
front coil on a 12v system, you need to use the ballast resistor A8nn 12250
A  or B ( 39-47 or 48-50 ).. and a dropping resistor  8NE10306.  Alternately
you can us a '12v' front mount coil like tisco supplies.. but you will still
need about 0.47 ohms of external resistance.. easiest way to do this is to
buy a (2) pack of radio shack 1 ohm ceramic power reistors and twist them in
parallel to make a 0.5 ohm resistor..  use that resistor only with the now
er coil.  Points don't care about voltage.. current is an issue, and it is
based on the conducting surface area of the points.. and that's about 4 amps
give or take.

Side mount N's have it easier.. you can get a true 12v side mount coil, like
a napa IC14SB and use no dropping resistor at all.  The primary resistance
of the coil is correct for 12-14 volt applications.

The condensor is no problem.. most of the automotive condensors for points
systems are rated over 100v before the dielectric breaks down.

Soundguy

<From: "Ace Russell" <acesongs at sprynet.com>
<Subject: [Ford-ferguson] Resistor & condensor 8N
<I've heard different things about whether to keep the inline resistor in
the
<circuit for a system that's been converted to 12V. It's a front-mount
<distributor, and the parts book at my local shop shows only one
condensor --
<doesn't distinguish between 6V and 12V systems. Something's heating up I
<guess, and causing a  power loss after about 15 minutes of heavy work
<(bushhogging). I hear lots of things about the coil, but I've tried 2
<different 12V coils, and the breakdown happens with each, so I'm suspecting
<something else.
<Do I need the inline resistor?
<Is there a 12V condensor?
<Any other ideas?





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