DanBailey

I have a 63 coupe 327. I'm looking for a place to connect a Electric choke that would only allow 12 volts when key is on?

Tampa Jerry

I hooked mine up to the 12 volt side (top) of the ballast resistor. Jerry

LB66383

JohnZ

When properly connected, the bottom end of the ballast resistor is the input side (12 volts from the ignition switch thru the grommet in the firewall), and the top end is the output side (reduced current to the coil + terminal).

DucatiDon

I've also seen oil pressure switches used

DanBailey

Thanks for the help

DanBailey

Thanks for info on the resistor JohnZ

DanBailey

So I should use the bottom of the resister that comes thru firewall Correct?

JohnZ

Yes, if you're looking for key-switched 12 volts.

DanBailey

Thanks again!

SI67

Since, it's in series with it, doesn't the resistor serve to reduce VOLTAGE, rather than current, to the coil?

JohnZ

That's part of the "great debate" the EE's love to get involved in; suffice to say that it minimizes arcing at the points so they last longer.

jim lockwood

I'm an EE so I'll jump in.

The series resistor serves to limit current to the coil and points. As a byproduct of limiting the current, the steady state Voltage you would measure at the (+) coil terminal with engine off and points closed would be less than battery Voltage.

Jim