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Old 08-30-2013, 12:38 PM   #1
huddy
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Default Convert Horn to 12V

BACKGROUND:
I am blessed that I finally convinced my best friend's widow to sell me his '30 Coupe. He died three years ago and during his last year, was mostly too ill to keep up with the routine maintenance. I have a lot of small stuff to take care of, but otherwise it's an excellent driver and a great 10-footer. Fortunately it's been kept in an enclosed garage in a desert climate, so it has not suffered from being allowed to sit. I've driven it several times during this period and it's fine. I'm trailering it to upstate NY in a couple of weeks where it will find its new home in my garage. I will go through the routine maintenance items before I do any significant driving.

TODAY'S QUESTION:
The coupe is equipped with a 6V pos ground alternator. I'm planning to eventually convert it to 12V neg ground, maybe as a winter project when I won't be driving it. One of the the items I had planned to do was rewire the horn field coil for 12V - I have the info from MAFCA and the enameled magnet wire on hand. The question is this: the horn is a rare GIM manufacture rather than the more common Sparton horns. Would rewiring the field coil ruin the value of this rare item? Should I just find another horn to convert and keep the GIM as is?
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Old 08-30-2013, 12:47 PM   #2
Bob C
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Default Re: Convert Horn to 12V

I guess I'll be the first to ask---why convert to 12V?

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Old 08-30-2013, 12:55 PM   #3
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Default Re: Convert Horn to 12V

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Originally Posted by huddy View Post
Should I just find another horn to convert and keep the GIM as is?
IMHO, yes.

It sounds like the 6 volt horn works, so leave it be.

Better to take a non-functional horn that needs to be rebuilt and do the conversion to 12 volts at the same time. Then you are not taking a good working 6 volt unit out of circulation, you are adding another horn to the pool.

I won't debate the merits of converting a car to 12 volts.
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Old 08-30-2013, 12:59 PM   #4
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Default Re: Convert Horn to 12V

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Originally Posted by Jim/TX/GA View Post
IMHO, yes.


I won't debate the merits of converting a car to 12 volts.


Didn't know there were any.
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Old 08-30-2013, 01:03 PM   #5
huddy
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Default Re: Convert Horn to 12V

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Originally Posted by Jim/TX/GA View Post
IMHO, yes.

It sounds like the 6 volt horn works, so leave it be.

Better to take a non-functional horn that needs to be rebuilt and do the conversion to 12 volts at the same time. Then you are not taking a good working 6 volt unit out of circulation, you are adding another horn to the pool.

I won't debate the merits of converting a car to 12 volts.
I think that's a subject for endless debate. How about just that I think there's some advantages and I'm willing to go to the effort and expense? The Coupe already has an alternator rather than a generator, as well as the 5-blade fan, so I wouldn't be doing anything to change its appearance from its current look.

My main concern is that the GIM horn is a rare item, would rewiring the field destroy its value as an artifact?

As for rebuilding it, I will probably have to do that anyway. It's not in the greatest of shape, needs to be repainted, cleaned, new brushes, etc. It does function, more or less.
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Old 08-30-2013, 01:20 PM   #6
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Default Re: Convert Horn to 12V

Just use a horn resistor (that the vendors sell) in the electrical circuit and leave the horn alone.
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Old 08-30-2013, 02:13 PM   #7
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Default Re: Convert Horn to 12V

Bratton's sell a horn resistor specially made to use on a 12-volt car with a 6-volt horn It fits out of sight inside the end housing of the horn. It is fully insulated and has the wire connections to make an easy hook up. I had one on a 12-volt 29 coupe for years. It worked well.

Horn resistor, part number 20050, $24.75, page 89 in their catalog.

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Old 08-30-2013, 03:20 PM   #8
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Default Re: Convert Horn to 12V

Quote:
Originally Posted by CarlG View Post
Just use a horn resistor (that the vendors sell) in the electrical circuit and leave the horn alone.
If you feel that you must convert then the resistor in the best bet.
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Old 08-30-2013, 05:10 PM   #9
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Default Re: Convert Horn to 12V

I used to help with an adoption forum, and circumcision was the hot button issue there. I guess 12V vs 6V is the circumcision of Model A'ers!

Seriously, this is a great source for information and I appreciate everyone's point of view.
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Old 08-30-2013, 05:21 PM   #10
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Default Re: Convert Horn to 12V

Yes, most that convert to 12 volt simply use the resistor and keep original horn
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Old 08-30-2013, 05:31 PM   #11
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Default Re: Convert Horn to 12V

I tried a few different value resistors on mine and it didn't sound as good as it did when I rewound the field.
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Old 08-30-2013, 06:18 PM   #12
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Default Re: Convert Horn to 12V

Sir,

It is you that must make the decision 6 volts or 12 volts.

You have heard from other guys of their preference and experience in using risistors, etc.

Works for some and not so for others.

The 6 volt systems works great. A 12 volts system seems to be the new thang these days. Difference strokes for different folks.

Should you have questions, I can be reached at: seaweed1996@yahoo.com

Regards,

Neil
THE HORN MAN
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Old 08-31-2013, 09:51 AM   #13
Mike V. Florida
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Default Re: Convert Horn to 12V

Quote:
Originally Posted by nstegall View Post
Sir,

It is you that must make the decision 6 volts or 12 volts.

You have heard from other guys of their preference and experience in using risistors, etc.

Works for some and not so for others.

The 6 volt systems works great. A 12 volts system seems to be the new thang these days. Difference strokes for different folks.

Should you have questions, I can be reached at: seaweed1996@yahoo.com

Regards,

Neil
THE HORN MAN
I agree with you!
At least he is changing because he wants to and doesn't believe he has to because 12v is "better".
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