jeffred

New User
I'm putting in a tune up kit in a '45 BN. I'm trying to figure out what type of coil to buy? It is a 12 volt with delco distributor. Currently there is an external resistor on the coil. I was shopping at Tractor Supply tonight and they had a coil that said it worked for both 6 volt and 12 volt, but the coil itself has no external resistor required written on it. So I got kind of confused. Part number is 396546R93.
 
Personally I try to put back what is on it....but you can go either way; internal or external. Not sure about the 6/12v both in one....these guys will know.
 
Well #1 you big problem is you where looking at China made junk so yep they tend to put info on things like coils that are not correct. No way a coil can work on 6 volts and 12 volts with out either not running well on 6 volts or running well but burning up points fast. Buy ignition stuff for places like NAPA or O'Reilly's and get good brand parts. Shoot I buy points for some of my stuff and it has a life time warranty on them so when they go bad I take them back and get new for nothing
 
Old is correct. No such thing as described. It might be labeled as such. A 6 volt coil will be about 2 to 2.5 ohms. So will a 12v coil for use with a ballast resistor (these two are essentially the same) A 12v coil for use with no resistor is truely a 12v coil. Jim
 
I bought one of those "no resistor needed" coils, at NAPA, and have been using it on a Delco distributor, with a 12 volt system, and it has worked fine, for the last several years.
 
If you disconnect the lead to the points, what is the resistance across the two small coil terminals. old and I are trying to figure out how a coil can be acceptable for use with or without a ballast resistor and be either too hard on points, or too weak on spark. Jim
 
IC14SB is NAPA number for 12 volt "no resistor needed" coil. It should have 3 ohms across + and - terminals. I would use it (or equivalent), get rid of the resistor and eliminate a future problem.
 
3 ohms yes but how many people have a VOM that is calibrated so as to get that reading out of say 10 different VOMs ?? I have 2 VOMs and I know if I test things with the 2 of them I get a different reading out of each so one can only get a ball park figure out of many cheap meters
 
From TSC's website....

-For 6 volt systems with or without external resistance
-For 12 volt systems with external resistance

Clear as MUD, eh? NOT really!
SOURCE....
 
True. Especially with cheap meters. On a coil resistance check I use a digital meter that will hopefully tell me if reading is closer to 1 1/2 ohms or 3 ohms.

I find a lot of the erratic readings at low ohms are in the probes and probe connections. I short the probes, note the reading, then check across coil and subtract probe resistance. Sometimes takes a few tries to reach a conclusion.
 

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