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Blue coil and resistor elimination


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Eliminate it !

 

Throw it in your neighbor's pool !!

 

Blue coils are pretty, but apparently the 123 does not need 3 ohms of resistance (like PerTronix or points would).

Some 123 people use a red coil, without an external resistor, fwtw.

 

https://www.bmw2002faq.com/search/?q=123 red coil&quick=1

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1 hour ago, '76mintgrün'02 said:

Eliminate it !

 

Throw it in your neighbor's pool !!

 

Blue coils are pretty, but apparently the 123 does not need 3 ohms of resistance (like PerTronix or points would).

Some 123 people use a red coil, without an external resistor, fwtw.

 

https://www.bmw2002faq.com/search/?q=123 red coil&quick=1

Er.....isn't the blue coil 3 ohms? 

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7 hours ago, '76mintgrün'02 said:

Eliminate it !

 

Throw it in your neighbor's pool !!

 

Blue coils are pretty, but apparently the 123 does not need 3 ohms of resistance (like PerTronix or points would).

Some 123 people use a red coil, without an external resistor, fwtw.

 

https://www.bmw2002faq.com/search/?q=123 red coil&quick=1

So your saying, remove it but , not reattach 

or connect wires ? 
or is there a place for the wires that ounce were

attached ?

Edited by Road trip
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6 hours ago, Hans said:

Er.....isn't the blue coil 3 ohms? 

 

Most of the time they are, but apparently there are exceptions.  You need to eliminate the resistor when you run a blue coil that has built in resistance.  Points and PerTronix want a total of around 3 ohms, whether external, or internal.  The 123 apparently only needs 1 ohm, so you can run red or black coils and eliminate the external resistor.

 

I am basing that on what people have said in the threads that come up in my link above. 

 

40 minutes ago, Road trip said:

So your saying, remove it but , not reattach 

or connect wires ? 
or is there a place for the wires that ounce were

attached ?

 

To eliminate the resistor, you simply run it's incoming wire directly to the coil.


Tom

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1 hour ago, '76mintgrün'02 said:

 

Most of the time they are, but apparently there are exceptions.  You need to eliminate the resistor when you run a blue coil that has built in resistance.  Points and PerTronix want a total of around 3 ohms, whether external, or internal.  The 123 apparently only needs 1 ohm, so you can run red or black coils and eliminate the external resistor.

 

I am basing that on what people have said in the threads that come up in my link above. 

 

 

To eliminate the resistor, you simply run it's incoming wire directly to the coil.


Tom

Ok, and maybe I'm having a bout of Covid brain, but if 123 needs one ohm, why would you remove resistor on blue coil to leave it at 3 ohm?

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15 minutes ago, Hans said:

if 123 needs one ohm, why would you remove resistor on blue coil to leave it at 3 ohm?

 

Gary wants to use his Blue coil with the 123 and asked how to wire it without the resistor.

 

Based on the bajillion posts on the topic, he might be better off with a red or black coil (with, or without added resistance), but that is not what his question was about.

 

123 apparently suggest a blue coil for a stock engine, so it "will work".  

 


Tom

Edited by '76mintgrün'02
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21 minutes ago, Road trip said:

My other o2 has the petronix 

what’s everyone’s advice on coil for that one ?1D96BD6F-E12B-4EF7-9E9F-F3C827BF6F9B.jpeg


As mentioned above, points and pertronix need about 3 ohms total resistance. This includes the coil and the resistor so if you measure the resistance of your coil you can add a resistor to bring the total value to 3ish ohms. There are several possible combinations. 
 

 

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I run a blue coil with a 123 dizzy. I replaced the resistor wire with a regular piece of wire. The resistor wire is found inside the stock blue wire sleeve. You need to replace the wire that looks somewhat like a speaker wire. If you find the splice, you can disconnect it and run your replacement wire in the blue sleeve to the dist. Pretty simple. 

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5 minutes ago, TodB said:

The resistor wire is found inside the stock blue wire sleeve.

 

That is true for the 74-76 model years.


The earlier cars used the ceramic style resistor shown in Gary's photo above.

 

In either case, you want to remove the resistor when using a 3 ohm blue coil.

 

That's true for points, PerTronix, or 123 ignitions.

 

Blue coil + resistor = wrong.

 

Tom

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