The Stovebolt Site Forums The Shop Area The Electrical Bay Coil resistance

I am rewiring my 48 truck with a 1967 250 Chevy truck engine. I do not have the HEI system but have points. I ordered a new ignition coil from LMC truck. When I use my multimeter with the positive probe on the positive side of the coil and the neg probe on the center where the wire goes over to the distributor I read 10 ohms. With that coil resistance do I need a wire resistor or ballast resistor upstream of the coil? Also with regard to hooking up the solenoid I know that the s on the ignition switch goes to the s terminal on the solenoid. There is a small terminal on the solenoid marked r and I think this should connect to the positive side on the coil to provide spark during cranking, also a second wire goes to the positive side of the coil and then to the run terminal on the ignition switch. I have searched the forum for this and think it may be correct but I wanted to check with the experts. Thanks for the help

if you have a connection direct to the coil +, it will be hot all the time and you won't shut it off with the key! that "2nd wire" should go to the ignition switch then to the coil, via the ignition resistor if needed - don't know about measuring the coil resistance, but it should say right on it if it does not need an external resistor, and most I've seen say if they DO need one ... LMC should have indicated in their catalog if it's internally resisted - if you ordered one for 67, it's likely internally resisted

Bill

thanks red, I will check it out with LMC

Hy sansaba1948, you can connect a wire from the "R" terminal on the starter solenoid directly to the coil positive terminal, when the engine is not being cranked to start the "R" terminal is not connected to anything else. You will have to run a wire from the ignition switch to the ballast resistor (if required) or directly to the coil, hope that helps.

Thanks 3b that does help a lot