resistors

[Peter Fetzek]

Hi all-

I'm working on re-wiring a '46 2n with a 12v conversion, serial # 216694.

Can someone tell me the difference between the larger dia. coil resistor and the smaller dia. one, besides one being about twice the price?

There's also an extra part directly below the stater switch. The battery cables are connected to it and there's a small wire connecting it to the switch. I don't see it on either the
parts list in the FO-4 manual or the other catalog I have. Can someone enlighten me?

thanks,
pete

 

[souNdguy]

On an OE 2n setup you would have the start switch back there a and the gen cutout relay. A pic would help us help you.

As for resistors and front mounts, I reccomend a new 12v 2.5 ohm coil like are commonly sold, and the OE dash resistor block.

 

[Peter Fetzek]

I'll try to figure out how to send a pic.

 

[Bruce (VA)]

" Can someone tell me the difference between the larger dia. coil resistor and the smaller dia. one, besides one being about twice the price? "

Assuming the resistors you have look like the ones in the pic......the difference is that one is a ballast resistor & the other is a fixed resistor.

Technology & materials being what they were in the 30's, that square coil would melt if it ran on much more than 4 amps for any length of time. (see tip # 38 for an example). In order to get a hot spark at the same time the starter was drawing max current from the battery, a ballast resistor was added in the ignition circuit. What that did was add about .3 ohms of resistance in the circuit, added to the 1.5 ohms of the coil. That got you 3.5 amps or so at start up. As the voltage increased when the engine was running to about 7.5 volts, the resistor heated up, adding more resistance in the circuit. 1.0 ohms hot, plus 1.5 ohms of the coil got you down to 3 amps or so to keep from melting the coil. The same rule (actually, Ohm's Law) applies to a 12v circuit. I= E/R. Current equals voltage divided by resistance.

Chances are you have a "6 volt" coil & the fixed resistor was added to reduce the running coil current to less that 4 amps. As soundguy said, life is simpler & easier if you remove the fixed resistor & use a 12 volt coil. (see tip # 30)

" There's also an extra part directly below the stater switch."

Yep, post a picture.

75 Tips