12 volt conversion question

[Charlie M]

What happens on a 12 volt conversion if nothing is used to reduce the voltage back to 6 volts at the distributor. Does the extra voltage burn up the points, coil, condenser, all the above and how long might it take to do so?

 

[John T]

If you apply 12 volts to a 6 volt rated coil: NOTE if done correctly its the voltage on the coil that gets reduced not the distributor which is downstream and after the coil and contains the points and condensor.

1) The coil can eventually (given adequate time ) overheat, maybe swell up maybe even spew out oil !!!!!!!!!!
2) Until such time as the coils Low Voltage Primary opens up or the LV primary circuit opens THE POINTS WILL BURN AND CARBON UP SOON
3) Other than points condensor and coil damage, the mechanical distributor should survive
4) TIME ?? May not be long before a 6 volt coil fries if full 12 volts is applied.

YES 12 volts on a 6 volt system can burn up coil and points, the condensor may survive

See what others can add to this Im sure theres more

John T

 

[used red MN]

Your can probably run quite some time, months, it may never bother the coil but it will definitely run hotter. A lot depends on how long you run you tractor at a time. The points will absolutely not last as long.

 

[john in la]

points pitting and burning will happen rather quickly
coil over time like said it depends on how long you run your tractor as the longer you run it the hotter it will get
condenser maybe never

 

[Janicholson]

If you apply 12 volts to a 6 volt rated coil: NOTE if done correctly its the voltage on the coil that gets reduced not the distributor which is downstream and after the coil and contains the points and condensor.

1) The coil can eventually (given adequate time ) overheat, maybe swell up maybe even spew out oil !!!!!!!!!!
2) Until such time as the coils Low Voltage Primary opens up or the LV primary circuit opens THE POINTS WILL BURN AND CARBON UP SOON
3) Other than points condensor and coil damage, the mechanical distributor should survive
4) TIME ?? May not be long before a 6 volt coil fries if full 12 volts is applied.

YES 12 volts on a 6 volt system can burn up coil and points, the condensor may survive

See what others can add to this Im sure theres more

John T

Adding to this info: There should be a ballast resistor added to the the coil input side so that the running voltage is about 6v. The use of a mid 60s chevy ballast resistor works, it is ceramic and maybe 2-1/2 inches long and 1/2 inch square. (cheap) the coil (if negative ground, should be wired so the negative small terminal of the coil is hooked to the distributor and the positive side hooked to the wire from the new resistor. The points and coil should draw about 4 amps, if no resistor, they will draw more like 7 to 8 amps and fail. Jim

 

[buickanddeere]

What happens on a 12 volt conversion if nothing is used to reduce the voltage back to 6 volts at the distributor. Does the extra voltage burn up the points, coil, condenser, all the above and how long might it take to do so?

Components will be subject to 4X the heat energy at 12V than they were at 6V .

 

[zuhnc]

@buickanddeere - Please explain. I don't understand this statement. zuhnc

 

[wore out]

@buickanddeere - Please explain. I don't understand this statement. zuhnc

https://sengpielaudio.com/FormulaWheel-ElectricalEngineering.htm

Here's something to look at 'til Buick gets back to you!

Use the "Power" segment of the wheel and plug some values into the formulas.

One is "Voltage Squared divided by resistance = power in Watts".

So for a Voltage of 6 Volts and a coil resistance of 1.8 Ohms, 6X6=36/1.8=20 Watts.

Double the Voltage to 12 Volts and we have 12X12=144/1.8=80 Watts, just like Buick wrote!

That is a simplified example, as we know, the actual electrical system operating voltages are around 7.4 Volts or 14.5 to 15 Volts, making for even MORE current/heat.

But, on the other hand breaker point dwell/duty cycle "chops" the current, making for LESS average current/heat than if it was a simple DC circuit.

 

[olddog]

If you apply 12 volts to a 6 volt rated coil: NOTE if done correctly its the voltage on the coil that gets reduced not the distributor which is downstream and after the coil and contains the points and condensor.

1) The coil can eventually (given adequate time ) overheat, maybe swell up maybe even spew out oil !!!!!!!!!!
2) Until such time as the coils Low Voltage Primary opens up or the LV primary circuit opens THE POINTS WILL BURN AND CARBON UP SOON
3) Other than points condensor and coil damage, the mechanical distributor should survive
4) TIME ?? May not be long before a 6 volt coil fries if full 12 volts is applied.

YES 12 volts on a 6 volt system can burn up coil and points, the condensor may survive

See what others can add to this Im sure theres more

John T

My experience... it'll last awhile working but.... say you are working the tractor and it stalls (run out of fuel, f'rinstance) and
it stalls exactly when the points are closed, and YOU FORGET TO TURN THE SWITCH OFF, you'll let the smoke out of the coil!
I suppose this could happen even with a 12V rated coil.

 

[Part Time Pete]

Years ago I bought an Allis D-14 from a jockey that had converted it to a 12 volt system. When I started using it, it was burning up points like crazy. Turns out he didn't change out the coil. I pulled a 12 volt coil off one of the junk cars in the ding weeds at the farm, and it cured the problem

 

[Fixingfarmer]

Coil needs changed and depending on which coil you pick you may need an external resistor or not. It’s not a bad time to put an 12v ignitor kit in... so if the coil has changed the volts to what a spark plug uses I don’t know if anything downstream will be bothered at least initially like everyone else said possibly years if you keep checking point cap. Condenser burnout maybe? Plug voltage is super high compared to anything we measure normally it’s not like it’s a direct 6 to 12 volt boost output of a 6v and 12v coil will be comparable. I will repeat I don’t have first hand experience of the longevity of this because I like to have the option to jump the tractors with the pickup and I suggest a conversion and the ignitor kit at the same time. The ignitor kit will be specific because it needs 12v power or 6v specifically depending on which plan is picked

 

[olddavid]

Why not just buy a 12 volt coil with internal resistor and use the existing 6 volt point set up. I saw a universal coil on Amazon for $20. If you want to be absolutely safe buy a 12 volt capacitor to go in the distributor as well.

 

[rvirgil_KS]

Why not just buy a 12 volt coil with internal resistor and use the existing 6 volt point set up. I saw a universal coil on Amazon for $20. If you want to be absolutely safe buy a 12 volt capacitor to go in the distributor as well.

I've never seen a 6 or 12 volt spec on points or condenser. They, and the coil are concerned about current through the circuit which is determined by combination or voltage to resistance ratio. That is what ohm's law is all about. A resistor added in series between 6 volt (1 1/2 ohm primary) coil and 12 volt battery source does drop the voltage but also drops the current through the circuit which is the main objective. Same points and condenser function with a 6 or 12 volt battery if circuit resistance is properly configured.

 

[John T]

I've never seen a 6 or 12 volt spec on points or condenser. They, and the coil are concerned about current through the circuit which is determined by combination or voltage to resistance ratio. That is what ohm's law is all about. A resistor added in series between 6 volt (1 1/2 ohm primary) coil and 12 volt battery source does drop the voltage but also drops the current through the circuit which is the main objective. Same points and condenser function with a 6 or 12 volt battery if circuit resistance is properly configured.

X2. Points are a current switching device and their withstand voltage rating is much much higher than a mere 6 or 12 volts IE same used on 6 or 12 volt systems. In order that points don’t burn prematurely current is limited to the 4 or so amp range. Again if a coils current is greatly increased over its rating they can overheat given enough run time. Fun sparky chatting with y’all. John T

 

[Janicholson]

Why not just buy a 12 volt coil with internal resistor and use the existing 6 volt point set up. I saw a universal coil on Amazon for $20. If you want to be absolutely safe buy a 12 volt capacitor to go in the distributor as well.

Not a flame, just best info: 12v coils operating on 14 volts do not have actual resistors in them. They are designed with wire size and number of turns to operate on the higher voltage, just like a 12v lightbulb instead of a 6v lightbulb when converting to an alternator. Jim

 

[olddavid]

I've never seen a 6 or 12 volt spec on points or condenser. They, and the coil are concerned about current through the circuit which is determined by combination or voltage to resistance ratio. That is what ohm's law is all about. A resistor added in series between 6 volt (1 1/2 ohm primary) coil and 12 volt battery source does drop the voltage but also drops the current through the circuit which is the main objective. Same points and condenser function with a 6 or 12 volt battery if circuit resistance is properly configured.

They may not sell the capacitors separately but you can get one out of a point kit for a 12 volt distributer. My guess is that the 6 volt capacitor would live with 12 volts on it. The points will work with 12 volts if you knock the current down. Agreed, you can use resistors to lower the voltage/current but it might take some experimenting to get the right resistance.

 

[olddavid]

Not a flame, just best info: 12v coils operating on 14 volts do not have actual resistors in them. They are designed with wire size and number of turns to operate on the higher voltage, just like a 12v lightbulb instead of a 6v lightbulb when converting to an alternator. Jim

I will give you that one. The resistor coil doesn't have a built in resistor just built in resistance.

 

[zuhnc]

Increased heat makes sense with 12V instead of 6V, keeping all other components the same. I am familiar with Ohms Law, and other electrical things, but Buick's statement didn't make any sense to me, without stating nothing other than voltage was changed. Might have been one of my "slow" days in interpretation!

Change voltage, change coils. Points and capacitor don't care, as their "ratings" are well above 6 or 12V. zuhnc

 

[HFJ]

i ran my 12 volt tractor with a 6 volt coil and no added resistor for ~ 8 years. the coil's still good.

 

[John T]

They may not sell the capacitors separately but you can get one out of a point kit for a 12 volt distributer. My guess is that the 6 volt capacitor would live with 12 volts on it. The points will work with 12 volts if you knock the current down. Agreed, you can use resistors to lower the voltage/current but it might take some experimenting to get the right resistance.

X2. The voltage rating of those old ignition condensers is wayyyyyyy higher than the mere 6 or 12 volts IE they arent labeled and sold as 6 or 12 volt capacitors and their voltage rating is much much greater. Same for the points which are a current switch designed for not much over 4 amps current switching duty and can be used in 6 or 12 volt systems as again their voltage rating like the condensers are wayyyyy higher then 6 or 12 volts. Good info good sparky chatting with you. Have a great rest of Ash Wednesday.