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6 volt to 12 volt: the horns


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The trouble with 12 volt conversions is that getting 6 volt accessories and gauges working is a chore. As a tech years ago, I never saw one single converted car come through my service bay that had everything working. To this day I have never seen one. I have heard a lot of guys protesting "But it worked before".

 

Reducing voltage in the traditional way (resistors) requires that you burn exactly as much energy in the resistor as the accessory uses. They won't work for everything, and they get really hot in use. There are other types of converters. You'll probably wind up with a gauge or 2 under the dash.

 

For the horn, try a Chrysler (ignition) ballast resistor. It wont get too hot just honking the horn, but mount it with plenty of space around it, and nothing flammable. On that bad day when the wire in the steering column shorts out and you can't shut the horn off, THEN it will get hot. You might need a separate resistor for each horn if the voltage falls too much.

Edited by Bloo (see edit history)
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Been there, done that......  I converted my ‘38’ to 12 volts.     The horns are the issue.     They will work on 12 volts - providing you don’t use them more than a few moments that they are needed.    I use mine momentarily - - a couple of short beep’s  works wonders.     Remember,  back in the mid ‘50’,  the car manufacturers reduced  the sound because they were very loud.    So using your old horns on 12 volts  has been a no problems for me.     I live in a very busy part of Florida with a ton of tourists trying to get around.   Drive your great old car as if your grandmother was in the front seat with you.    My conversion was smooth.    I got 12 volt light bulbs to replace every thing including head lights.     The manufacturers did not give you enough candle power bulbs for todays needs.    I’ve added ‘37’ Ford  LED tail lights to supplement the low powered tail lights.   E-mail me @ Oldbuickjim@gmail.com for some pix of what I did.     Trust me,  those LED tail lights were a life saver when I had a front tire BLOW OUT at night on the Interstate.    I pulled off on to the side and the LED  tail lights were very bright so I could be seen for oncoming traffic.    Waited for the Road Ranger to keep the traffic away from me so I could change my tire and get on my way - - -.

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Converting to 12 volts is a issue - -  I can utilize modern equipments.   Your original 6 volt starter will work nicely on 12 volts.   You will have a problem with the heater fan.    My biggest issue was I NEEDED air conditioning here in Florida.   That requires 12 volts to make that happen.  The rest was just come along items.    I’m modifying my newest addition to my 2 car  garage.    I found a 1935 series 58 Buick.   Mom says if it’s full, no more cars.  I am converting it to 12 volts also.    It will have over drive so I can drive and keep up with traffic.    Buick guys can get over drive mod’s easily from the guy who did  Lloyd Young’s  mod’s.    I now own two of them.    I drive 60 to 65 mph easily with the engine turning only 2200 to 2350 all day.     My ‘38’ Buick coupe cruises 65 mph and 2350 rpm.   Long trips easily - my longest was 1800 miles round trip.   Ya man - - -

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BTW,   Only the gas gage needs protection.   Change the bulbs,  add the RUNTZ voltage unit to keep it working and the rest need nothing.   Don’t use anything but the RUNTZ protester.   There are others that are cheeper but I wouldn’t trust them.   A failure in that area gets to be very expensive to fix.   The amp meter is a current device, not voltage.    The temp gage and oil pressure are mechanical.    This is only my opinion but I’ve been there,  done that.   

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I have decided to do a due output within my generator housing!  So I will be keeping the car, it’s drivetrain, all of its gauges and stock lighting running on the 6 volt side of things.

 

then the 12v output will run anything else I want to charge or run, up to about 20amps.

 

 

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1 hour ago, Tinindian said:

I always understood that an ammeter did not care about voltage (pressure) only about amps (flow).

 

True. A 1936 Buick charging system, IIRC, is a third brush setup with a maximum output of about 17 amps. I don't know how much full scale is on the ammeter, but probably not near enough for a typical alternator conversion. You would probably have to add a shunt to the ammeter if you wanted to use it.

Edited by Bloo (see edit history)
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Morgan I would never tell someone else what to do with their car, after all it’s their car!  I might not always agree with other people’s decisions but in the end, it’s their property and their hard earned cash!

 

I’ve worked in the automotive business for 20 years and I see people do some amazing things to their vehicles to make them their own, I also see some that makes me think “what the hell are they thinking?!”  But at the end of the day, it isn’t my vehicle!  Nor is it my $$....

Edited by Crazyfamily (see edit history)
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Well,  I see that this opinion on keeping our cars running in todays conditions has ruffeled some feathers.   I enjoy driving my  ‘38’ Buick in todays traffic and if that is what it takes to keep it safe, it’s my opinion.  My Buick is not a trailer queen,  I drive mine.....

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I daily drive a 36 Pontiac on 6 volts. I don't even own a trailer. It is true I don't drive it in the winter, but that is because I am trying to preserve it, not because there is any trouble with the electrical system. I have had several 6 volt winter cars over the years. I drove a bathtub Nash for a couple of winters. What a great car. They go in the snow better than you would think, and the heater is amazing.

 

 

 

 

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One of my biggest enjoyments while driving is listening to music.  With past restorations I have had the factory radio upgraded internally with digital components that allow for bluetooth and satellite radio without destroying the visual integrity of the original features.  Sadly, this covert upgrade requires a 12 volt system.  I honestly hate converting the car, but I want to enjoy 1930s swing music while driving, not crackling sounds from a two-bit AM radio station.

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14 hours ago, Jim Nelson said:

Well,  I see that this opinion on keeping our cars running in todays conditions has ruffeled some feathers.   I enjoy driving my  ‘38’ Buick in todays traffic and if that is what it takes to keep it safe, it’s my opinion.  My Buick is not a trailer queen,  I drive mine.....

 

 Ah well, Jim, I am with you, but we are all different, I guess.  Wish folks could just answer the questions or ===.  Mom still comes to mind. If you can't say something good ====.  Well , you know the rest.   The old story of which is better, red head or blond? Never will there be a consensus.  Aren't old cars fun?

 

  Ben

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Keep in mind that resale values plummet when you modify a car from stock original. Nobody wants a 1926 Buick with the engine removed from the front and replaced by a corvair engine in the back, the wheels replaced by caterpillar tracks, and the body removed and replaced by an oscar meyer weiner. Converting 6 V to 12 V is nice but you have to convert it back if you expect to sell it.

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First let me say my electrical knowledge is second handed at best...... I would think you could find a modern electronic (mystery) box that would

drop 12V to 6V that way the things that were originally 6V would be happy and the new/modern 12v things would get the voltage they need.

Just an example the Reatta (and Riviera, Eldorado, etc) in the late '80's had a box call the "central power supply"....it converted 12V to 7V for some of the

low voltage electronics used in the digital dash, and CRT.   I'm told they actually wanted 5V but everything I can find says the central power supply put out 7V.

These are not plentiful and I don't know what amount of accessories they would drive,  but it is just a thought.

Below is the diagram from the Reatta/Riviera service manual.

 

Horns....back in the '50's when I started driving I put those old long horns (6V Chrysler were plentiful) on several cars that were 12v and never remember any of them failing.    One of Murphy's sub-rules is "if you don't know if it will work there is a 50/50 chance it will"

CPS1.jpg

Edited by Barney Eaton (see edit history)
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I have a spare 6 volt horn, I hooked it up to 12 volts and it works find. It's a little louder and has a slightly higher pitch, but it works fine and nothing smokes. It's the buzzer type of horn used from the 30's to the 70's, not the motor driven horn of the Aoooga years.

 

Hook your horn up to 12 volts and see how it works.

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My first car in 1964 a `47 Chevy, g-ma and g-pa`s old car with a froze and busted block. I put a `55 chevy engine/trans/r-end and converted to 12v, installed `56 Oldsmobile gauges(12v)into the original cluster, changed voltage regulator and all the bulbs. I left the original horns, relay, and all the wiring. My younger brother has the car now and those 6v horns are still working. Really loud!

Edited by pont35cpe (see edit history)
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I considered doing that  BUT  you must take the first horn and isolate it from the firewall.   The mounting of the horn becomes the half of the circuit to run 6 volts.   If you want to do it,  mount the firstborn on a insulating mount and then run the power thru the first horn on the way to the second horn.....    Its more trouble than its worth.   The 6 volt horns work well as long as you don't "lay on" the horn.   A few momentary beeps in todays traffic should be enough.     They were wired for high current so the 12 volt power will work for a long time if treated like an old man should be....

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A buzzer-type horn works by breaking the circuit over and over again. If you put them in series, the results could be really screwy. Try it on the bench before putting any time into insulating one horn.

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Or you run two separate systems,  a 6v and touch nothing in the car so it keeps its originality, AND a separate 12v system to run modern items of your choosing!

 

This is the way I am going.....

 

 

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32 minutes ago, Crazyfamily said:

Or you run two separate systems,  a 6v and touch nothing in the car so it keeps its originality, AND a separate 12v system to run modern items of your choosing!

 

This is the way I am going.....

 

 

Aren't you going to have to run an alternator for the 12V alternate?

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8 hours ago, MargaritavilleBuick said:

Aren't you going to have to run an alternator for the 12V alternate?


No Sir, converting the generator to a dual output so everything will be retained on the 6v side but it will also be able to output 12v as well. Changing over to two 6v Optima batteries wired in series so one battery will run the 6 v side of the vehicle and then combined batteries will take care of the 12v side so it will retain the stock look aside from having two batteries.  Everything can be removed easily if needed and besides the generator being rewound no other modifications will be made.

 

AND if needed I can switch out the modified generator out and go back to a stock purely 6v generator if needed!  Best of both worlds in my opinion.  

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5 hours ago, Crazyfamily said:


No Sir, converting the generator to a dual output so everything will be retained on the 6v side but it will also be able to output 12v as well. Changing over to two 6v Optima batteries wired in series so one battery will run the 6 v side of the vehicle and then combined batteries will take care of the 12v side so it will retain the stock look aside from having two batteries.  Everything can be removed easily if needed and besides the generator being rewound no other modifications will be made.

 

AND if needed I can switch out the modified generator out and go back to a stock purely 6v generator if needed!  Best of both worlds in my opinion.  

 

Well that sounds like the way to go....but....where are you mounting the second six volt?  Currently my car has a flimsy cradle under the seat that barely holds one battery.

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For 6 volt horns on 12 volt systems, I use a series resistor made of nichrome wire.  The proper length was determined  by connecting a voltmeter across the operating horn, and moving a tap (clip lead) along the nichrome until it reads six volts. When I found the correct length of nichrome, I slipped a piece of thin fiberglass sleeving over the wire. From there the nichrome can be wound around a finger and held in place with a tie-wrap.

 

Another method is to use a low resistance, high current potentiometer or rheostat in series with the horn and adjusting it for six volts across the horn.  From there the potentiometer resistance can be measured and that value used in a length of nichrome.

 

Nichrome wire and sleeving came from Mouser as I recall. 

Edited by BuicksBuicks
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On 3/2/2020 at 5:52 AM, MargaritavilleBuick said:

 

Well that sounds like the way to go....but....where are you mounting the second six volt?  Currently my car has a flimsy cradle under the seat that barely holds one battery.

I have a second battery tray but my goal is to mount two 6v Optima batteries side by side in one battery tray!  I’m never parting w the car so having two batteries isn’t a big deal to me but the dual output Genny and the two batteries should fix me up perfectly!

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The nichrome wire barely gets warm. I suppose it might get rather hot if I kept the horn blasting constantly.  I use the horn so seldom the wire doesn't even have a chance to get warm. Even so, the fiberglass sleeving provides heat protection and self-shorting prevention.

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