[bsb1955]

Gents: My 55 Chevy was missing the ballast resistor when I bought it. I think the previous owner had used HEI system for drag racing then took it out when he sold the car to me and replaced the original points distributor. I have installed a Petronix I in the distributor to replace the points, but don't want to run the chance of burning out the system because the resistor is gone. Looking at the front end wiring diagram I can't tell which wire goes to one side of the ballast resistor and where the other one goes to. So my question is, where does the incoming wire to the resistor come from (and what color wire on a stock harness) and where does the other end go (to the coil I think but which side!):confused0006: Thanks for your help! Brian:bowtieb:

 

[RustyCrank]

If you have a coil with internal resistor, you wont need the ballast resistor. Otherwise, one side will be 12+ hot with key on, and the other side will get 12+ in the start position only. The purpose of this was to bypass the ballast resistor during start to put full 12 volts to the coil during cranking.

 

[acardon]

On a 55, there is a brown wire from "IGN1" on the switch to the top terminal of the resistor. There is a dark green wire from the bottom terminal of the resistor to "IGN2" of the switch. Also from "IGN2" on the switch, there is another dark green wire to the +coil terminal. [URL="On a 55, there is a brown wire from "IGN1" to one end of the resistor". See drawing of ignition switch in Section 12 page 5 of the assembly manual. For some reason the link from the library doesn't work????

 

[bsb1955]

Shows you how little I know. Corlen, I didn't know you could even get a coil with an internal resistor or how to tell that it has one. I was going to replace the coil anyway, so am I to understand that having a coil with an internal resistor negates the need for a ballast resistor at all? :confused0006: And Arcadon I understand now that the resistor is linked to the ignition switch directly at ign1 and ign2, and not to the coil at all. That clears up a lot for me, thanks. Now to figure how to determine, from under the hood, which dark green wire goes to the resistor and which one goes to the coil. Hmmm. Brian:bowtieb:

 

[bsb1955]

A light bulb just went off in my head. It doesn't matter which dark green wire I attach to the ballast resistor or to the coil because they are both connected to IGN2, right? How easy is that? Brian :bowtieb:

 

[acardon]

A light bulb just went off in my head. It doesn't matter which dark green wire I attach to the ballast resistor or to the coil because they are both connected to IGN2, right? How easy is that? Brian :bowtieb:

Right, I was just going to write that. Pun intended. :smile:

 

[bsb1955]

Thanks for the verification, Don. Too easy now! I will be wiring this resistor up this weekend. Thanks again. Brian:bowtieb:

 

[RustyCrank]

Thats right, the coils with internal resistors are designed to go from no resistance cold to XX ohms when heated up which gives full 12 volts for the first minute or so, then drop to 6 volts after the engine starts to save the points. These should be labeled on the coil "internal resistance" or "Resistance Coil". (I had to go dig one up in the shop to see what they say) I believe they began using them in the late 60's. I cant find the factory wiring diagram that I used to have but it's pretty simple - ign on goes to one side, the other goes to the + on the non-resistor type coil. The IGN 2 goes to the coil side of the resistor to effectively bypass the resistor and send a full 12 volts to the coil during cranking. Then when you let off the start position and back to run, the 12 volts hitting the resistor gets cut in half to 6 volts for the points. So check with a test light in case you think the wires are not stock or just for peace of mind.

 

[bsb1955]

Corlen, so a resistor coil should be pretty much a standard anymore I would think, and not hard to find. Thanks for your input. Brian:bowtieb:

 

[acardon]

Corlen, so a resistor coil should be pretty much a standard anymore I would think, and not hard to find. Thanks for your input. Brian:bowtieb:

Not necessairly true. There may be some hy-bred electronic or CD discharge ignitions just befor the HEI distributor was introduced but most cars had a resistance wire to the coil in the 60's and early 70's. Here is a coil for a 72 Chevy. Note the AC-Delco discription.... http://www.rockauto.com/catalog/x,carcode,1028304,parttype,7060

Pertronix has a Flame thrower coil for the Pertronix I and a different Flame thrower II coil for the Pertronix II module. ....http://www.summitracing.com/parts/PNX-40011/

 

[bsb1955]

Well, no worries. I will wire up my ballast resistor as original and get myself a new high speed coil. Brian:bowtieb:

 

[RustyCrank]

Here's a link to one

http://www.kansasselectproducts.com/servlet/the-7/12v-ignition-coils-point/Detail

 

[bsb1955]

Corlen, thanks for the link. I was checking O'Reilly and other big name stores and not having any luck. And talk about cheap! :shakehands: Brian :bowtieb:

 

[RustyCrank]

Yeah, I'm finding out that you really can do a lot of valuable research on the web these days and save a lot of bucks. A good example is Custom Auto Sound radios that are about the only thing you can find new with knobs to fit the old dash. The first one I saw was $189 plus handling and shipping. I then found it at Sound Move for $159, free shipping and no sales tax.

Check out this place I found for specialty connectors http://www.delcity.net/
Some things are bulk quantity, but a look at the weather pack prices! Last swap meet I bought some for $2 a pop thinking it was a great deal compared to Schmucks at $5 a side!

For a long time I wasn't sure you could trust online purchases, but now the UPS driver has his own parking spot and coffee cup at my place!

 

[bsb1955]

Corlen: Thanks for the radio info and wiring link to delcity. Brian:bowtieb: