The Ford Barn

Muddyfeet · 03-23-2015, 08:04 PM

Do I need a resistor in a 6 volt points system. Late thirty's flathead dual point old style coil.

Walt Dupont--Me. · 03-23-2015, 08:12 PM

Yes, it usually on the inside of the firewall, It cuts the 6 volt down to 3-1/2 to 4 volts. Most Ford parts places have them, maybe Napa. Walt

Muddyfeet · 03-23-2015, 08:31 PM

Thanks for the info.

JSeery · 03-23-2015, 09:14 PM

The whole panel looks like this, a fuse for the lighting circuits and the resister for the coil. Power from the starter solenoid goes to one side of the fuse (Y). This is also the connection point for generator (YB), the ignition switch (YB) and the cigar lighter (YG). The other side of the fuse connects to the lighting switch (YR) and the pillar lights switch (B-BL). The ON side of the ignition switch connects to the resister (BR) and the gauges (BG). The other side of the resister connects to the coil (R).

(Y) Yellow
(YB) Yellow/Black
(YG) Yellow/Green
(YR) Yellow/Red
(B-BL) Black/Blue
(BR) Black/Red
(BG) Black/Green
(R) Red

koates · 03-24-2015, 04:31 AM

More specifically you require the correct FORD resistor, part number 18-12250 and not just any old (or new) ignition resistor from your local parts store. 6 volt ford V8 ignition coils from 1932 to 1948 are designed to operate in series through the resistor on 4.5 volts with the engine running. Typically the system voltage with engine running and generator charging (engine revved up some) is around 7.5 volts. Regards, kevin.

51504bat · 03-24-2015, 10:14 AM

Sponsored Links (Register now to hide all advertisements)

I just converted my '39 p/u to 12 volts and I have the original 6 volt resister assembly that was working when removed. PM me if interested.

Tim

supereal · 03-24-2015, 04:54 PM

The correct Ford ignition resistor has an element made of nichrome wire, such as in old toasters. As the voltage in the system increases, the winding heats up, increasing resistance to keep the voltage to the coil in the 3-3.5 range. Ordinary voltage droppers don't do this, usually resulting in burned points. If you convert to 12 volts, have the coil rewound so you can eliminate the resistor on them firewall.

03-23-2015, 08:04 PM	#1
Muddyfeet Junior Member Join Date: Aug 2014 Posts: 12	Resistor for 6 volt points Do I need a resistor in a 6 volt points system. Late thirty's flathead dual point old style coil.

03-23-2015, 08:12 PM	#2
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: Resistor for 6 volt points Yes, it usually on the inside of the firewall, It cuts the 6 volt down to 3-1/2 to 4 volts. Most Ford parts places have them, maybe Napa. Walt

03-23-2015, 08:31 PM	#3
Muddyfeet Junior Member Join Date: Aug 2014 Posts: 12	Re: Resistor for 6 volt points Thanks for the info.

03-24-2015, 04:31 AM	#5
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,082	Re: Resistor for 6 volt points More specifically you require the correct FORD resistor, part number 18-12250 and not just any old (or new) ignition resistor from your local parts store. 6 volt ford V8 ignition coils from 1932 to 1948 are designed to operate in series through the resistor on 4.5 volts with the engine running. Typically the system voltage with engine running and generator charging (engine revved up some) is around 7.5 volts. Regards, kevin.

03-24-2015, 10:14 AM	#6
51504bat Senior Member Join Date: Sep 2013 Location: SoCal-Redlands Posts: 3,039	Re: Resistor for 6 volt points Sponsored Links (Register now to hide all advertisements) I just converted my '39 p/u to 12 volts and I have the original 6 volt resister assembly that was working when removed. PM me if interested. Tim __________________ Making the simple complicated for over 30 years.

03-24-2015, 04:54 PM	#7
supereal Senior Member Join Date: Jul 2014 Location: Iowa Posts: 1,634	Re: Resistor for 6 volt points The correct Ford ignition resistor has an element made of nichrome wire, such as in old toasters. As the voltage in the system increases, the winding heats up, increasing resistance to keep the voltage to the coil in the 3-3.5 range. Ordinary voltage droppers don't do this, usually resulting in burned points. If you convert to 12 volts, have the coil rewound so you can eliminate the resistor on them firewall.