MTFCA Forum

Looking for a replacement cover for this battery horn in my 1924 Fordor. Is it a klaxon horn and is it 6V or 12V? The previous owner stuck a 12v battery in the car and this blew every light bulb in thr car. Will running the horn on 12v also burn it out or is it safe on 12v? The horn makes the ahooga sound, but it’s sickly sounding and probably needs a rebuild or adjustment. Any guidance would be appreciated.

Not T, nor A. A has a flared trumpet.

Allan from down under.

That's a Klaxon-type horn. I don't know what it came from. It looks very old, and is almost certainly a 6 volt device. It may be an aftermarket item. Running 6 volt equipment on 12 volts will destroy it.* A Model T is supposed to be 6 volt negative ground.

* A stock Model T ignition system can be operated on 12 volts. There's no reason to do so if the car's magneto is operating as it should. The ignition system will perform best and stay "in tune" far longer when operating on the Ford AC magneto.

A Model T with the original electrical equipment in good condition is very easy to start. With the original system, there are several available options for starting and running the car, and a run-down battery or other failure usually won't prevent starting and running the car.

Do NOT run the engine of a Model T without a battery in place. Doing so will destroy the generator, if the car has one.

Thanks guys. I’ll search for a nice 12v ahooga horn and bracket and swap it out and keep this old one with the car. I’m planning to leave the car on 12v and replace all bulbs and upgrade the starter and generator to units internally rebuilt for 12v. The magneto does work, but I’m going to run the car on battery with the lights on and and keep it on a trickle charge when parked. If anyone has any of those parts for sale, feel free to message me with details and price.

Enter the can of worms…..

Any reason why you want to go to 12 volt?
I’m 100% not opposed to 12 volt & in all candor actually once had a T on 12 volt system when I was young & too broke to rebuild/refresh my motor & repair the magneto field coil.

On the horn, the cover is held on with 1 small bolt at the bracket holding the windings. All you probably have to do to get it working correctly is clean (spray electrical cleaner) the brush dust off the contacts, make sure brush’s are free moving and a little 3n1 oil. Don’t be liberal with the oil. Don’t laugh but you can use a soup can or veggie can to make a cover. If you want to be Avant garde, get a can with ridges if not a smooth side can will work too. The trick is not being watched to closely when you take your small tape measure into the store and going down the canned food isle measuring OD & length. Depending on what your car looks like or your humor level, you may choose to leave the label on or take off & paint. The horn you have is much louder than the model T horn and doesn’t sound like a calf getting castrated.

Your car will be more reliable and perform better with properly rebuilt 6 volt parts. It will also have more market value, as well as having more antique appeal.
You can run the car all day long with the lights on on magneto. That's how I run my car. Running the lights (selectively) avoids overcharging the battery.

There is no magic in 12 volt systems,and they are no more durable or reliable than 6 volt systems.

The original Model T electrical system offers a level of redundancy that modern style replacement systems do not.

The horn the OP has is a motor horn, not a vibrator horn.

Well no joke, Welcome to the party, I meant brushes not magnets.

There were only a few horns made back then that were 12 volt, like the North East that Dodge Brother used till about 1926 ($), so yes, I would say it is 6 volt. To use on a 12 volt system, it would work but not as it should, so you would never get the sound that would be right. It would need a voltage reducer or would need the armature rewound for 12 volts.
More than likely it needs to be cleaned, lubed and adjusted anyway. While Klaxon was a brand name, this may not have been made by them, unless there it is stamped or has a tag on it.
My suggestion would be, if you can't find and actual cover, you might try the soup can approach. Find a tin can that is the correct diameter and length (shorten if needed), drill a mounting hole in the back, paint and install. Would not be the first time that something like this has been done.

Come on people, lets help John with the problem at hand, not offer your opinion about 12 vs. 6 volts.

Most of those Brush horns have the brushes tied in parallel for six volts.

If you figure out the circuit, they can be hooked in series for 12 volt operation.

It has been a long time since I did the change, but that was with one of the newer 12 Volt horns sold by J. C. Whitney and it worked fine.

The acid test is to try the horn and look for smoke.

A Sugary Sam yam can might fit the Model A style oogah horn. That horn looks like it used a smaller diameter cover. An old steel 12 oz. beer can might be a good fit. I'd look for a Blatz can.

12 volts on a T opens a new can of worms, more often than not.

That is close to the size of a Bendix cover.

One of those might be trimmed down to fit.

I think You have a Kaxet horn.

Andre
Belgium

There's probably a spin-on oil filter cannister that would nearly duplicate that cover. An oil filter cannister would be about the right gauge. They come in a wide variety of diameters and lengths.

Andre perhaps if possible could you provide the dimensions of the cap cover. Best John

Assuming the horn is 6 volt, could a ballast resistor be used to step the 12 v to 6 volt for the horn only?

Thanks all, this does look like a vintage 20s Klaxon Klaxet horn! The horn works fine on 12v and makes a decent sound and I didn't notice any smoke when activating it in the garage. I guess some of these horns were originally wired for 6v and others for 12v...I don't know which one this is since the cover is missing. The brushes and magnet/winding definitely need a good cleaning and lubrication which I will take care of before installing a new cover. This guy in Australia seems to be an expert with these horns and I might reach out to him to see if he has any spare covers or brackets to make it look complete again: http://www.klaxonhorns.com/. I also found this Klaxon horn video on YouTube: https://www.youtube.com/watch?v=QiJbWB27l2g

I'm not attached to this horn, so if anyone has a source for an original looking black 12v ahooga horn or a good used one they'd like to sell, let me know.

.........................

Wanted to follow up and provide and update on my Klaxon 8c horn. I disassembled, cleaned, lubricated and adjusted the horn and now it works great, even on 12v. It does spin a little fast and doesn’t sound perfect, so I’d like to installed a resister to lower the voltage to 6v. Does anyone have a link to the correct part or instructions on how to wire that up? I also ordered another rebuilt Klaxon 8c from eBay today for $200 so I have a motor cover and a spare horn in case I need it. Can’t wait to use this ahooga horn once I get the car back on the road!

https://drive.google.com/file/d/133h3uu ... p=drivesdk

As a complete "wild a$$ guess", I would try putting an ignition ballast resistor in-line with the power wire.

Looks like a horn I have on one of my cars. Mine is 6 volt. Actually if your starter is still wound for 6 volts, the coils will work on 6 volts. The car won't have quite as much power as on magneto, but I ran one for about 10 years on 6 volts until I repaired the magneto. If you decide on a distributor, you can get a 6 volt coil for it and run on 6 volts. That way you won't have to change anything else from original equipment.
Norm

Jerry VanOoteghem wrote: ↑

Wed Mar 15, 2023 10:14 am

As a complete "wild a$$ guess", I would try putting an ignition ballast resistor in-line with the power wire.

OK, I’ll Google ballast resistors and see if I can find one. Thanks

Auto supply stores may still stock ignition ballast resistors. A typical value is 1.5 ohms. With any significant, sustained load, the resistor will get hot and the resistance will increase. That ought not be an issue in a horn circuit.