Ignition Question

[buickal]

I want to switch over from points to a pertronix igniter system. My Ford Jubilee was previously switched to 12v but has the original 6v coil so there is a resistor to step down the voltage. Can I upgrade to a 12v coil by simply removing the resistor and connecting to the 12v coming into the resistor? With the pertronix I don t have to worry about burning points with too much voltage.

Thanks

 

[Bruce (VA)]

You have the concept backwards.

The resistor is in front of the 6 volt coil to reduce the voltage to the coil, not the points. Points do not care about primary voltage; they work just fine on 6v or 12v. (
ever see points advertised as 6v or 12v points?)

Your 6v coil does however care about primary voltage. The internal resistance of your 6v coil is likely around 2.25 ohms. Run 12v into that long enough and it will melt. A
12v coil, on the other hand, has about 3.25 ohms of internal resistance and will take 12v all day with no problems.

So, if you want to remove the resistor, then install a 12v coil like the NAPA p/n IC14SB.

See tip # 30 for more info.

And BTW.........if you think you do not need to worry about to much voltage to the EI, leave the key on and see what happens.
75 Tips

 

[Jim.ME]

Isn't the proper coil, or coil and resistor combination, for the benefit of the points, not the coil. Yes, the same contact point sets are used for 6 or 12 volts, I agree points don't care about voltage, but they are amperage sensitive for best life. The proper resistance in the coil, or ballast resistor and coil combination, limits the current flow (to about 4 amps) through the coil to the points, to prolong the life of the points. A 6-volt coil, without a ballast resistor in the primary ignition circuit, fed by 12-volts is going let too much current flow to the points, burning the contacts thus decreasing the point life.

 

[buickal]

(quoted from post at 05:20:50 06/18/23) You have the concept backwards.

The resistor is in front of the 6 volt coil to reduce the voltage to the coil, not the points. Points do not care about primary voltage; they work just fine on 6v or 12v. (
ever see points advertised as 6v or 12v points?)

Your 6v coil does however care about primary voltage. The internal resistance of your 6v coil is likely around 2.25 ohms. Run 12v into that long enough and it will melt. A
12v coil, on the other hand, has about 3.25 ohms of internal resistance and will take 12v all day with no problems.

So, if you want to remove the resistor, then install a 12v coil like the NAPA p/n IC14SB.

See tip # 30 for more info.

And BTW.........if you think you do not need to worry about to much voltage to the EI, leave the key on and see what happens.
75 Tips

I get the resistor reduces voltage to the coil, but I presumed that output voltage of a 6v coil to the distributor is very different than a 12v coil. Perhaps this is my mistake in how I am thinking about the 2 coils.

 

[buickal]

This is how I was thinking about it but not being well versed in electrical couldn t properly verbalize it. It does prompt another questionis there any difference (Benefit) to going from a 6v coil/resistor setup to a 12v? I have seen info indicating that the pertronix systems work best with 12v coils (and according to some one has to bypass the resistor to get a 12v lead) so I was thinking I needed to change from a 6v coil to a 12v. I am going to replace my coil either way because it looks like it was made by Adam back in the Garden (really old).

 

[HFJ]

(quoted from post at 10:27:20 06/18/23)
This is how I was thinking about it but not being well versed in electrical couldn t properly verbalize it. It does prompt another questionis there any difference (Benefit) to going from a 6v coil/resistor setup to a 12v? I have seen info indicating that the pertronix systems work best with 12v coils (and according to some one has to bypass the resistor to get a 12v lead) so I was thinking I needed to change from a 6v coil to a 12v. I am going to replace my coil either way because it looks like it was made by Adam back in the Garden (really old).

i don't know which unit you purchased. i put a 91247 in my 2N. i left my key on. it smiled and continued to work. that's why they get the big bucks for that model.

put a 12 volt coil on. they're dirt cheap.

don't hesitate to contact pertronix with any question. they will tell you to remove that resistor. on my 2N, they wanted me to bypass the OEM resistor as well (the Jube doesn't have one of those.)

ed: sorry, i see you haven't gotten one yet. get a 12 volt coil, dump that resistor, and look at the 91247

This post was edited by HFJ on 06/18/2023 at 06:40 am.

 

[Bruce (VA)]

Isn't the proper coil, or coil and resistor combination, for the benefit of the points, not the coil?

Once again..........no.

As an example, you have a 6v side distributor 8n with points. You convert it to 12v with a 12v coil.

Are the points now going to burn up quicker?

The quickest way to burn up a set of points is to leave the key on when they are closed.
75 Tips

 

[Hobo,NC]

Millions of EI set ups were were produced using 6V coils yours is no exception. Get the resistance correct life will be good. The proper 12V coil just takes the calculation out of the equation that's all.

I have no problem using a 6V coil on your set up and I sort of prefer it : ) and that's depending on how lazy I am at the time of the install.

12V coils are so common and cheap @ $20 I keep a few new ones on the shelf they will not rot : ) If need be I can throw one on cross my fingers and hope for the best. Once in a blue moon its a fix, now that was EZ, my beer never got cold.

That's why I am not a member of the "coils are robust they are the last thing to give issues" Cuzz yes they do and can be the hardest part to diagnose and eliminate the issue.

 

[buickal]

(quoted from post at 07:08:05 06/18/23) Millions of EI set ups were were produced using 6V coils yours is no exception. Get the resistance correct life will be good. The proper 12V coil just takes the calculation out of the equation that's all.

I have no problem using a 6V coil on your set up and I sort of prefer it : ) and that's depending on how lazy I am at the time of the install.

12V coils are so common and cheap @ $20 I keep a few new ones on the shelf they will not rot : ) If need be I can throw one on cross my fingers and hope for the best. Once in a blue moon its a fix, now that was EZ, my beer never got cold.

That's why I am not a member of the "coils are robust they are the last thing to give issues" Cuzz yes they do and can be the hardest part to diagnose and eliminate the issue.

Thx for the info. I was most interested in your coils go bad comment. I have been told/read that coils work or don t but in my mind (and maybe it s just all in head) that coils can work but not work as they should. I know the 6v coil is still functioning as the tractor cranks and runs. There was a bit of a miss and I noticed the points need to be replaced and the plugs are nasty. I figured this presents an optimal time to eliminate points and improve things. The 12v coil and resistor part of the equation confused me because I searched and found conflicting info. I am going to look up the coil someone posted a part number for and just get rid of all the 6v components.

 

[soaked]

I bought a 1244A Ignitor last fall. The folded instructions, dated 6/4/21,
warn not to use solid core spark plug wires.
Agree, get a 3 ohm coil.
Suggest call pertronix for first hand info.

 

[Hobo,NC]

(quoted from post at 21:29:15 06/18/23)

(quoted from post at 07:08:05 06/18/23) Millions of EI set ups were were produced using 6V coils yours is no exception. Get the resistance correct life will be good. The proper 12V coil just takes the calculation out of the equation that's all.

I have no problem using a 6V coil on your set up and I sort of prefer it : ) and that's depending on how lazy I am at the time of the install.

12V coils are so common and cheap @ $20 I keep a few new ones on the shelf they will not rot : ) If need be I can throw one on cross my fingers and hope for the best. Once in a blue moon its a fix, now that was EZ, my beer never got cold.

That's why I am not a member of the "coils are robust they are the last thing to give issues" Cuzz yes they do and can be the hardest part to diagnose and eliminate the issue.

Thx for the info. I was most interested in your coils go bad comment. I have been told/read that coils work or don t but in my mind (and maybe it s just all in head) that coils can work but not work as they should. I know the 6v coil is still functioning as the tractor cranks and runs. There was a bit of a miss and I noticed the points need to be replaced and the plugs are nasty. I figured this presents an optimal time to eliminate points and improve things. The 12v coil and resistor part of the equation confused me because I searched and found conflicting info. I am going to look up the coil someone posted a part number for and just get rid of all the 6v components.

Yes, a coil can check good ohm out in spec and still be bad. If one coil is confusing lets hope you never have to deal with a vehicle that has 4,6,8 are 10 ignition coils.

You can take the IC14SB number remove SB and cross it over to your favorite brand. SB is Napa's code for their cheaper line of ignition parts.

IC14SB works and is the ticket without any of the confusion. : )

 

[Eman85]

For my money I'd buy a 12V coil ditch the resistor and maybe a new set of points if it needs it.

 

[Jim.ME]

(quoted from post at 10:02:09 06/18/23) Isn't the proper coil, or coil and resistor combination, for the benefit of the points, not the coil?

Once again..........no.

As an example, you have a 6v side distributor 8n with points. You convert it to 12v with a 12v coil.

Are the points now going to burn up quicker?

The quickest way to burn up a set of points is to leave the key on when they are closed.
75 Tips

It may just be our wording; however, you and I will have to respectfully disagree on whether the change is for the benefit of the coil or the points, or maybe we can agree both coil and points benefit.

I agree with you that if you convert a 6-volt side distributor to 12 volts with a 12-volt coil (or use a proper resistor with the 6-volt coil) you are keeping the amperage flow through the coil to the points in the acceptable range for point life because of the coil's resistance. And the points should not burn up quicker, all things being equal.

However, if you convert it to 12 volts and leave the original 6-volt coil in service with no resistor, the amperage flow through coil to the points is higher because the resistance through the 6-volt coil is lower (than the resistance of a true 12-volt coil or the 6-volt coil with the addition of a proper ohm resistor) and the contacts will have a shorter life due to the increased current flowing through them.

I am not saying the 6-volt coil won't run hotter or might not last as long on 12 volts due to heating, but how any discussions on these forums have been about changing the coil to a 12-volt, one or adding a properly sized resistor to a 6-volt coil, to have the proper resistance to keep the amperage at the points in the 3 to 4-amp range when doing a 12-volt conversion? To me that is benefitting point life.

To the OP's original question, I would do away with the old coil and resistor and install a new 12-volt coil of the spec called for by Pertronix for the kit he is purchasing.

 

[Tim PloughNman Daley]

Well stated, Hobo man! 6V Coil is fine - if it ain't broke... Many guys put too much into this. The problem starts because they can't figure out the 6V/POS GRN
system and/or get the points set and distributor timed properly so assume they need to get a 12V setup. When that results in same problems, they assume EI is the next
move. There is nothing wrong with 6V, 12V, or even EI, but you better know what you are doing with each. EI just eliminates the need to muck with points. Guys spend
small fortunes on million dollar high voltage (Flamethrower) systems needlessly. How many kilowatts do you think your system requires? Get one thing wrong with EI and
you start smelling the smoke you just let out of system. Most problems are the result of fellas' failure to understand wiring systems and taking their own shortcuts.
I've never had a desire nor need to convert to 12V or even EI but have worked on plenty. All my N's are and have always been 6V/POS GRN, run purfect because I know how
to tune-up correctly. From what I've read on EI, it runs best on 12V, but I see PERTRONIX sells a kit for a 6V/POS GRN setup.

FYI: 9N/2N W/PERTRONIX & 12V:

Tim Daley (MI)

 

[Abbby]

buickal. Lots of noise here. When you switch to electronic ignition spend a few extra bucks and replace the 6 volt coil with a 12 volt.

 

[buickal]

(quoted from post at 02:59:39 06/19/23) Well stated, Hobo man! 6V Coil is fine - if it ain't broke... Many guys put too much into this. The problem starts because they can't figure out the 6V/POS GRN
system and/or get the points set and distributor timed properly so assume they need to get a 12V setup. When that results in same problems, they assume EI is the next
move. There is nothing wrong with 6V, 12V, or even EI, but you better know what you are doing with each. EI just eliminates the need to muck with points. Guys spend
small fortunes on million dollar high voltage (Flamethrower) systems needlessly. How many kilowatts do you think your system requires? Get one thing wrong with EI and
you start smelling the smoke you just let out of system. Most problems are the result of fellas' failure to understand wiring systems and taking their own shortcuts.
I've never had a desire nor need to convert to 12V or even EI but have worked on plenty. All my N's are and have always been 6V/POS GRN, run purfect because I know how
to tune-up correctly. From what I've read on EI, it runs best on 12V, but I see PERTRONIX sells a kit for a 6V/POS GRN setup.

FYI: 9N/2N W/PERTRONIX & 12V:
<center><img src=https://i.imgur.com/ZNylSVwl.jpg></center>

Tim Daley (MI)

I agree with what you have said about people sometimes thinking EI will solve a problem that is really something else. My main reason for switching is go to a system that does not require points that have to be replaced and when they are set. The conversion just makes it easier than dealing with points. However, I know my jubilee has a 6v coil despite the charging system having been converted to 12v. I also know the pertronix requires 12v power to work so I would have to wire it to the 12v feed into the resistor. Rather than keep the 6v coil and resistor and having to wire the pertronix to the 12v side of the resistor block, I was thinking I could go to a 12v coil and remove the old 6v coil and resistor..but not being an electrical guru I wasn t sure. Didn t really find any help on YouTube. I m new to these old Ford N series tractors but I do love them. Small, maneuverable little workhorses despite the minimal HP (my jubilee has around 29HP I think).

 

[Btzj02]

Just to muddy the waters a bit. When a switch,(points) is opened the strength of the arc created is based on the amperage and the reactive of the circuit. If the reactance is balanced then the arc is easily extinguished and the points don't burn up. If the reactive is not balanced the points will eventually burn up and, spark will be lost at the plugs. A Coil creates Inductance reactance and a Capacitor,(Condenser) creates capacitive reactance and they balance each other out. A healthy Coil and a healthy Condenser is necessary to minimize burning at the points.

This is an over simplification, of course!

 

[JMOR]

(quoted from post at 09:15:33 06/19/23) Just to muddy the waters a bit. When a switch,(points) is opened the strength of the arc created is based on the amperage and the reactive of the circuit. If the reactance is balanced then the arc is easily extinguished and the points don't burn up. If the reactive is not balanced the points will eventually burn up and, spark will be lost at the plugs. A Coil creates Inductance reactance and a Capacitor,(Condenser) creates capacitive reactance and they balance each other out. A healthy Coil and a healthy Condenser is necessary to minimize burning at the points.

This is an over simplification, of course!

etting down to the basic fundamentals, the condenser provides a path for coil reactive current, for enough of a time period for the points to open gap sufficiently, so as to not arc across the point gap. Without it, much of the coils stored energy is lost in the arc across points instead of going to the spark plug.
As for the resistor reducing "voltage" to the coil, ....at the instant the points close (on a 12v system with 6v coil and resistor), the coil voltage will be 12v, not 6v (no initial current means no voltage drop across resistor). As current increases over the RC time constant, the current thru coil/resistor results in a voltage drop across the resistor, thus over time , the coil voltage drops from 12v to ~6v. Here it is in my scope photo:

 

[WILLIAM4536]

# 4 fires before # 3 is this right.

 

[HFJ]

yes. the firing order on an N is 1-2-4-3.