which electronic ignition/ distributor?
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
Ok, I follow all of that. I fully understand the current varies. I just don't see how the voltage can go any higher than 12v -1.3 Ohm allows. I can see it going a bit lower, as the current load increases, but not higher when the current load decreases, at least not higher than the rated voltage drop across the resistor. There has to be a drop in voltage when going thru a resistor, regardless of current load/AMPs.
If that's not what you're saying, then I guess we are *sorta* saying the same thing, just in a different way.
It's kinda like a restriction in a fluid flow. The PSI and volume will only be so high after the restriction, unless the flow is stopped beyond the restriction. It can then equalize the PSI. On the other hand, a PSI regulator *should* maintain a steady PSI at any flow rate, even if the flow stops.
I would think a resistor would treat electrical voltage in the same manner as a PSI regulator does for fluids.
If that's not what you're saying, then I guess we are *sorta* saying the same thing, just in a different way.
It's kinda like a restriction in a fluid flow. The PSI and volume will only be so high after the restriction, unless the flow is stopped beyond the restriction. It can then equalize the PSI. On the other hand, a PSI regulator *should* maintain a steady PSI at any flow rate, even if the flow stops.
I would think a resistor would treat electrical voltage in the same manner as a PSI regulator does for fluids.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
A resistor is more like a mesh screen in a pipe. While you might maintain the same pressure (voltage) upstream, the fluid flow (current) through the entire pipe is now reduced. Interestingly enough, though, there are electronic devices that can regulate voltage despite a changing load on the system. That's exactly what the voltage regulator does.
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
The voltage doesn't go higher - it goes lower just like you think. For example, if at one point in time, the current is 500 mA, then the voltage available to the module is now 12 - 1.3*0.5 = 11.35 V, when in fact it should just stay at 12 all the time. My point is that the voltage at the module needs to be 12 all the time, not 12 sometimes, but sometimes 11, maybe sometimes 10.35, then back up to 11.4, etc, etc.
This is only true if there is finite current. If there is no current through the resistor, then there is no voltage drop across the resistor (voltage does not go through, current does). Again, V = I*R, so if I = 0, then V = 0.
Again, 100% correct.
A resistor is more like a mesh screen in a pipe. While you might maintain the same pressure (voltage) upstream, the fluid flow (current) through the entire pipe is now reduced. Interestingly enough, though, there are electronic devices that can regulate voltage despite a changing load on the system. That's exactly what the voltage regulator does.
This is only true if there is finite current. If there is no current through the resistor, then there is no voltage drop across the resistor (voltage does not go through, current does). Again, V = I*R, so if I = 0, then V = 0.
Again, 100% correct.
A resistor is more like a mesh screen in a pipe. While you might maintain the same pressure (voltage) upstream, the fluid flow (current) through the entire pipe is now reduced. Interestingly enough, though, there are electronic devices that can regulate voltage despite a changing load on the system. That's exactly what the voltage regulator does.
Without using technical math and such, a resistor that is rated to drop 12V to 9V can and will actually vary the output, say from 7V-9V depending on load, but will never allow the output to exceed 9V, unless the input is raised. The output can also drop lower than the rated output, if the input is lowered.
I know my example is "dumbed down" and isn't *technically* accurate in real world numbers, just a simplified way to show what I was trying to say.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 784
From: Simi Valley, CA
1960/86 FoMoCo vehicles: There are three different resistor wires due to their lengths.
COLF-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-37).
61.49" long / color coded Pink / 1.30-1.40 ohms resistance / #16 gauge wire.
---------------------------------------------------------------------------
D1AZ-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-84A).
60" long / color coded Red w/Green stripes / 1.30-1.40 ohms resistance / #16 gauge wire.
----------------------------------------------------------------------------------------
D7AZ-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-213).
49" long / color coded Red / 1.30-1.40 ohms resistance / #16 gauge wire.
COLF-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-37).
61.49" long / color coded Pink / 1.30-1.40 ohms resistance / #16 gauge wire.
---------------------------------------------------------------------------
D1AZ-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-84A).
60" long / color coded Red w/Green stripes / 1.30-1.40 ohms resistance / #16 gauge wire.
----------------------------------------------------------------------------------------
D7AZ-12250-A .. Resistor Wire-Ignition Coil (Motorcraft DY-213).
49" long / color coded Red / 1.30-1.40 ohms resistance / #16 gauge wire.
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
That's too funny, all these posts and the tread originally posted 10 years ago. I guess these should drop off after a certain time with no replies. Well just goes to show why people come here for their questions, we reply to anything in an effort to help. I'd be surprised if this truck is still with this guy.
Cranky Old Guy
Joined: Mar 2008
Posts: 3,562
Likes: 6
From: Raphine, Virginia
That's too funny, all these posts and the tread originally posted 10 years ago. I guess these should drop off after a certain time with no replies. WEll just goes to show why people come here for their questions, we reply to anything in an effort to help. I'd be surprised if this truck is still with this guy.
Senior User
Joined: Jun 2011
Posts: 146
Likes: 0
From: Bristow, VA
True, good discusion, just funny none of us caught onto it being a 10 year old tread till fmc400 noticed it back on the 8th.
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New User
Joined: Mar 2012
Posts: 2
Likes: 0
points to electronic ignition.
Hello. I have an old 76 F-250 with a 75 360 in it. The 76 has the electronic ignition box on the firewall but the 360 has points. I have put new carb on it but just cant get it to run right. I think its the points and timing. I am wanting to convert to a good electronic system but dont know what i need? Any help would be greatly appreciated. thank you.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
This thread must be haunted, because it keeps being brought back from the dead. 
If your '76 is already wired up for factory electronic ignition, it's probably easiest to get a 360 distributor that would have come with Duraspark and update the engine to what the truck would have already had. Factory Duraspark is an excellent system and this is the shortest path to getting the job done.
Note that while electronic ignition is superior to points, an engine should still be able to run well on points. You need to troubleshoot what's going on instead of throwing parts at it. Set the point gap and timing to the factory spec - if it doesn't run well there, something else is going on that may not necessarily be solved by upgrading.
If your '76 is already wired up for factory electronic ignition, it's probably easiest to get a 360 distributor that would have come with Duraspark and update the engine to what the truck would have already had. Factory Duraspark is an excellent system and this is the shortest path to getting the job done.
Note that while electronic ignition is superior to points, an engine should still be able to run well on points. You need to troubleshoot what's going on instead of throwing parts at it. Set the point gap and timing to the factory spec - if it doesn't run well there, something else is going on that may not necessarily be solved by upgrading.
New User
Joined: Apr 2017
Posts: 1
Likes: 0
Have you tried putting a simple transistor inline with your points? This is a poor man's pertronix but it only costs 3 bucks and will make your points last forever.... longer than the rubbing block anyways. Its so cheap i carry a spare in my glove box. If you want to know how to do it i can send you a pdf file with the instructions.
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1978, 360, distributor, egnision, electronic, f250, ford, ignition, points, replacement, replacing, transistor, truck, trucks, windstar
