I don't know but you usually want the coil to get full voltage for starting and the resistance (wire or ballast) to be on the coil power when running so the coil don't overheat. I use a ballast set up in this way as a backup ignition (run MSD 6T normally).
I can't tell. Standard Motor Products UC15 is the right type, it says on it "12v no external resistor required"
Check the resistance. A coil for use with points without a resistor should be 3 ohms across the terminals. The term "12v" is a misnomer because a 1.5ohm (or even less) coil could also be used without a resistor on certain 12v systems.
I would NEVER use a resistor coil on a points system on a vehicle I used. I want the byp*** full volt system as the factory built. Battery voltage dips during startup and this means less to the coil using a built in resistor. The only exception is if your building a car where “hiding” every part and wiring is important to you in shows..
Under what conditions does the coil really need full voltage to start the engine? I've had a few without the byp***, and they never had any issues...
In that case I am going to move this to the main board and away from the off topic forum. I would use a 1.5 ohm coil and a 1.5 ohm ballast resistor if it were my car
Froze up and locked up can have the same meaning but not always. We will have a high of 5 or 6 F this weekend. Dan
Your right I just heard the salt truck go by so nothing I care about is going out on the road. I was thinking more historically, in the early 70s when all I could afford was old cars at 30 below the egnition needed all the help it could get. I wired the egnition on my model A with the byp*** because I could not because it would really need it. Phil
I now need to shut up and not complain. We’re knocking on 50 F for the highs the past week or so, and I bundle up like Ralphies little brother in “a Christmas story”.
In AZ I can see why. Now try that on a good running carb'd engine with well used but still good ignition components (plugs especially) in 20 degree weather with thick oil and you might see the need. I have and you need every bit of power to fire up under those conditions. It ****s when it doesn't and you have to work on it in the cold. An internal resistor coil would work in a warmer climate, especially for garaged cars. But as a former mechanic I have always tried to do things the way they should be and not cut corners, but that's on me...lol. Others may see it differently.
As a former mechanic, I've been having a lot of fun figuring out what I can get away with, and it turns out I can get away with an awful lot of shortcuts
I have a few Blue coils and a GM coil that are internally resisted and a few for external resisted (1.5 vs 3.0). In fact I have a NOS GM coil (made in Japan) on the panel truck now, starts perfect hot or cold (47 on cold mornings). BTW be aware that not all blue coils are made the same. Older story but still applies. https://www.ratwell.com/technical/BlueCoil.html
Yes agree on blue coils. Ones from Germany were top shelf and you pay for them. The south of the border ones resistance is all over the place. Need to check resistance before buying them.. Ones from South America were quite good. Been thru this with a beetle restoration. Hope this helps.
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