Ignition Coil

[Rustedjunk]

I have been doing a lot of reading on ignition coils and I want to make sure I don't make a mistake. I wired my early style 47 Super Deluxe with the 21A-14401 harness. I have the switch, key, and button ignition and start. My car is going 12V. I'm running a points distributor with the "crab" cap. Am I good with the Bosch 00012, or should I go with something different that will need an external resistor? I have been confused with all the posts. I just want to get in my car and drive. If I get the Bosch, how should I wire it? Thank you all who help, and Happy Father's Day.

[Rustedjunk]

I'm trying to get advice if I'm good to spend money on the Bosch or go with an entirely different setup.

[Charlie ny]

RJ,
No better coil, pricey for sure but so what. I've used one for 4 years no sweat.
The NAPA 12v coil IC64 or IC14 by Echlin is fine too. All internal resistor coils
Charlie ny

[Rustedjunk]

Thanks Charlie! How should I run the wires to the coil? I know the negative one goes to the condenser on top of the distributor. Since I won't have a need for a external ballast resistor, where do I run the wire from the positive side of the coil to?

[flatjack9]

The ignition wire from the switch goes to the negative side of the coil. The positive side of the coil goes to the distributor.

[deuce_roadster]

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Since the point are going to ground, I always thought that if you had a neg ground system, the negative side of the coil went to the distrib, conversely, if you have a positive ground system, the + side goes to the distributor. NO?
My 12 v neg ground brand X car has the neg side of the coil going to the distributor.

[JSeery]

Originally Posted by flatjack9

The ignition wire from the switch goes to the negative side of the coil. The positive side of the coil goes to the distributor.

Not with a negative ground car. Should be the other way around, + to the ignition wire and - to the distributor.

[Rustedjunk]

This is how my car was grounded by the previous owner.

[V8COOPMAN]

Originally Posted by Rustedjunk

This is how my car was grounded by the previous owner.

If that RED cable is connected to the POS battery post, and the black tape-wrapped cable is attached to the NEG battery post, then you have a NEG ground system, which means the NEG post on coil goes to distributor.....POS coil post to ignition switch (12v source). Looking at your pic, I'm not sure that your 12v to ignition switch is wired to the correct side of your solenoid. 12v to the ign. switch should come from BATTERY side of solenoid. DD

[BUBBAS IGNITION]

There is no better coil than the Bosch Blue # 00012.

https://www.amazon.com/Bosch-00012-9...lue+00012+coil

[flatjack9]

Originally Posted by JSeery

Not with a negative ground car. Should be the other way around, + to the ignition wire and - to the distributor.

The OP did not say anything about it being changed to negative ground. Originally it would have been positive ground.

[JSeery]

Very few 12v conversions are positive ground. It could be done obviously, but I've never seen it.

[Drbrown]

My '47 has a 12v negative ground system, which I understand is the (more) normal method of electrical conversion. I run a crab points dist with Bosch Blue coil (internal resistor). Ignition key (+) goes to coil (+). Coil (-) goes to dist. condensor.

[Charlie ny]

How's it running Dr. ?
Charlie

[Greg58]

I changed my 50 years ago, I also changed to a internal resistor coil. Since the condenser is nothing more than a trigger capacitor I changed it to match the coil. I've been running this set up for a dozen years.

[Rustedjunk]

V8COOPMAN, you are right. That picture was taken before I changed where the dash harness connects to. These two pics are showing the harness connect to the positive battery side. My question is on the starter solenoid there are two posts on the front. One with an "I" over it and one with an "S" over it. You can see it in the picture. I assume the smaller black wire which is for the start button goes to the "I" terminal. So does the positive terminal on the ignition coil go to the "S" terminal on the solenoid?

[JSeery]

"S" is for start, "I" is for ignition. The starter button connects to the "S" and has to be from a "hot" source (positive battery source). This requires the two terminial pushbutton found on some later models. You can normally tell them apart because the one wire buttons are chrome and the two wire are black. The "I" terminal connects to the coil IF you are using an external ballast resistor.

[Rustedjunk]

Originally Posted by JSeery

"S" is for start, "I" is for ignition. The starter button connects to the "S" and has to be from a "hot" source (positive battery source). This requires the two terminial pushbutton found on some later models. You can normally tell them apart because the one wire buttons are chrome and the two wire are black. The "I" terminal connects to the coil IF you are using an external ballast resistor.

If the "I" terminal on the solenoid is for if you have an external resistor coil, then where do you connect the positive terminal to on a internal resistor coil? I have no idea where to wire things to start and run when it comes down to the ignition coil and the start button? I'm literally running blind here. LOL! I just ordered the Bosch Blue 00012 like Bubba said. Thanks Bubba! Would someone be willing to draw a diagram or show me pictures of what they did using the original harness? That's the only way I'll be able to understand.

[40cpe]

You should connect the "+" side of the coil to the "I" or "coil" (depending on how it is labeled) terminal on the ignition switch.

[rotorwrench]

These questions always come up when using modern components on older cars. Many of the more modern cars had a full voltage bypass to the coil during the starting phase. As soon as the starting phase was over, it reverted back to the ballasted current to coil from the ignition switch. The I terminal would not be necessary for a system that doesn't use a cold start bypass system. A person could use a 12-volt single pole start solenoid on there if they wanted. Apples and oranges though, since it doesn't make much difference.