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Old 05-03-2020, 12:34 PM   #21
30 Closed Cab PU
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Default Re: Any 6 Volt coil will do?

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Originally Posted by katy View Post
Wrong, an autotransformer has only one winding, an ignition coil has two.

I see two types (attached). The second one is used in an A?


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Old 05-03-2020, 02:09 PM   #22
Patrick L.
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Default Re: Any 6 Volt coil will do?

I don't think an autotransformer can convert enough voltage. Of course I may be wrong.
I've only taken apart a couple ignition coils when I was young. All that I'm aware of have 2 coils. I think it takes that to covert such a low voltage to such a high one. How can the collapse occur with one coil.
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Old 05-03-2020, 03:43 PM   #23
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Default Re: Any 6 Volt coil will do?

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Originally Posted by Patrick L. View Post
How can the collapse occur with one coil.
Low tension ignition systems existed in the past. The points were the spark plug gap. There was a cam that opened and closed the points in the combustion chamber.
It was not a popular system, once something better was invented.

Take a battery, a headlight relay or similar, and some lengths of wire. Connect the relay to the battery so it clicks on. You don't feel that voltage yet, right? Now let the wire fall from one end of the relay while a finger is still on the relay contact. You feel the voltage spike yet?
That's what happens when the field collapses through the coil that generated it.
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Old 05-04-2020, 09:58 AM   #24
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Default Re: Any 6 Volt coil will do?

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The second one is used in an A?
Correct.
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Old 05-12-2020, 03:50 AM   #25
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Default Re: Any 6 Volt coil will do?

Just as a matter of interest; why are coils for electronic ignition different?

Manuel in Oz
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Old 05-12-2020, 08:34 AM   #26
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Default Re: Any 6 Volt coil will do?

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Quote:
Originally Posted by Manuel View Post
Just as a matter of interest; why are coils for electronic ignition different?

Manuel in Oz
They don't need to be. The electronic ignition only replaces the mechanical points.
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Old 05-12-2020, 08:42 AM   #27
barkleydave
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Default Re: Any 6 Volt coil will do?

There is really no such thing as a 6 volt coil.
The coil does not care.
Ohms dictates voltage to the ignition

Simple rule: The lower the Ohms (resistance) the higher the passthrough voltage to ignition.

1.4 Ohm coil no resitor for a 6 volt system
1.4 Ohm coil with resistor for a 12 volt
3.0 Ohm coil no resistor for a 12 volt

I have three antiques all running Pertronix 1 Model A has the 1.4 setup with resistor and the other is a 3.0 setup both run equally well. I have one modual which has run 20 years since I put it in and have not touched it since!

The lower the Ohms the higher the voltage sent to the points/or ignitor if electronic.
Example marine electronic ignitors call for a .6 ohm coil which is hot!

Last edited by barkleydave; 05-12-2020 at 08:47 AM.
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Old 05-12-2020, 01:09 PM   #28
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Default Re: Any 6 Volt coil will do?

Anybody using a three OHM coil on six volts ? I use a three OHM coil on twelve volts and a 1.5 OHM on six volt . A 1.5 OHM coil can be used on twelve volts if a resister is used at the connections .Works good for me .
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Old 05-12-2020, 01:35 PM   #29
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Default Re: Any 6 Volt coil will do?

Just for kicks I tried a 3 ohm coil on 6 volts. Still worked, was a blue spark on the plugs, but seemed weak, kinda like having a 6 v coil in backwards. My opinion is 3 ohm coil may be an issue on poorly maintained carb(rich)/ignition systems (poor points, plugs, connections) especially at idle, or with lights on, the battery is draining and battery voltage droops.
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