57 G/H Tach

[jrlemke]

I need some info on a '57 G/H tach. Is the sending unit attached to the back of the tach? How do I test it without installing it in a car? What is it worth? I can buy a dash from a '57 G/H that was installed in a custom car. The speedo and boost gage are gone and the overlay is shot. Some of the switches are there as well as the tach. Do I need anything else to use the tach in my '61 Hawk? Thanks

[Don Jeffers]

I need some info on a '57 G/H tach. Is the sending unit attached to the back of the tach? How do I test it without installing it in a car? What is it worth? I can buy a dash from a '57 G/H that was installed in a custom car. The speedo and boost gage are gone and the overlay is shot. Some of the switches are there as well as the tach. Do I need anything else to use the tach in my '61 Hawk? Thanks

The '57 Golden Hawk tach sending unit installs between the distributor and the distributor cap. The body of the sending unit is about one inch tall, its diameter virtually the same as the distributor body. The unit is made of a dark brown bakelite plastic type material.

The sending unit's shaft mates over and to the distributor shaft and is driven by it. The distributor rotor mounts to the top of the sending unit in the same manner as it does to a distributor. The distributor cap mounts on the top of the sending unit in the same manner it mounts to a distributor. The assembly is held together by distributor cap clips.

The sending unit is an electrical generator, voltage varying with distributor speed. The sending unit cable comes out of the side of the sending unit and connects to the tach cable by a plug. The tach reads the voltage generated and converts that voltage to a needle displacement calibrated in RPM. The '57 Hawk tach is not particularly accurate and the distributor-sending unit-cap is not a good tight shaft assembly. I'm sure it generates some spark scatter all on its own.

Nothing more is needed but a working sending unit and tach. The sending unit converts the mechanical rotation of the distributor to electrical energy to the tach. All self contained.

This description is from memory from ~ 53 - 55 years ago. If my memory has failed on some point, I'm sure someone will comment. I have seen my sending unit since that time, probably at least 30 years ago. It and the tach are adrift somewhere in my parts pile. I have no idea what the units are worth and have no interest in searching for mine. I only respond because I have first hand knowledge and to help answer your question.

If you find a '57 sending unit, it could be tested by spinning the unit up at the rotor shaft by gently pushing the shaft against a wire wheel on a bench grinder or other clever rig and see if your tach registers. You could also read the voltage output of the sending unit, but I have no idea what the voltage read out should be.

A new Stewart-Warner tach can be bought that is very similar in appearance to the '57 tach and is quite accurate. All the '57 Golden Hawk instruments can be replaced by similar looking new S-W units. Your tach could be converted to a modern electronic counter, but that would be a shame as original tachs are not common. The conversion would likely cost more than a new tach.

Unless you are building a 100 point restoration car or just get lucky and find the tach parts at reasonable prices, going with a new S-W unit is a good compromise. Good luck with your search.


The overlays are sometimes available in decent shape. Maybe yours could be repaired. You could make a new overlay in aluminum or steel and cover it or your original with some of the amazingly good looking engine-turned plastic appliques. Or alternatively, make one of a good looking wood veneer.


The boost gauge is a combination vacuum-boost. I don't recall the range, but again new s-W units are available and are very similar in appearance.

[GinettaG12P]

I bought an original 1956-61 Studebaker tachometer sans sending unit at a swap meet and then found that sending units were virtually nonexistent, and converting the tachometer to work without the sending unit would be quite expensive. After a bit of internet research, I found a tachometer that looks quite a bit like the original, but is a simple three wire (plus lighting) hookup. The tachometer model is a Teleflex 82288P Marine Tachometer and I am very happy with its appearance and performance in my 1959 Silver Hawk. The tach will not pass for original, but it is close. I have no affiliation with the manufacturer or seller of these tachometers.

[DieselJim]

Studebaker International has sending units. I believe the extra clips to hold the cap are hard to find.

[PackardV8]

Be aware when buying a sending unit at a swap meet or on Fleabay, there are at least three variants and maybe more.

1. The '56 Golden Hawk's Packard V8 used an Autolite distributor.
2. IIRC, the later Hawks were Delco.
3. There's a GM Delco version which is different than the Stude Delco.
4. Then, there's the '55 Speedster 6V version.

The sending units all look the same, just fit different distributors.

Another FWIW, Brent Hagen out in Portland has some '56J senders and rebuilds them all. ghawk352@effectnet.com

In fact, thinking about it, I've got at least three tachs of various years and a couple of senders. Anyone interested PM me.

jack vines

[jrlemke]

The tach has what appears to be a sending unit attached to the back of the tach itself. It has a cable coming out with a plug on it. This is not on the tach (original?) that was in the car.

[brngarage]

How 'bout some pictures to clarify this?

[garyash]

Tach sender

The tach sender is a simple rotary switch. The lower end of a rotating cylinder gets a 12 volt contact from a carbon brush. The upper end of the cylinder has an insulating plastic section about 1/3 the way around. Two brushes at 180 degree separation alternately pick up the 12 volt signal, though there is some period when both brushes are energized. The three wires connected to the brushes lead out to a short cable with a strange 3-prong plug which looks a little like the base of an old octal radio tube. A mating connector on a long cable carries the voltage to the tach housing. Inside the tach housing is the head of an old-style cable driven tach, now driven by an electric pulse motor. So, the faster the distributor turns, the higher the pulse rate, though the pulses are always 12 volts. The faster pulse rate makes the motor turn faster and turns the tach needle, just like a speedometer.

If, like me, you feel absolutely compelled to disassemble the sender to see what's inside, then you can inspect the brushes. Do this on a large table where the little brush springs won't fly out of sight. Great, now it's apart. Fun, wasn't it? Yeah, so to put it back together, take a manila file folder and cut a strip about 3/4" wide and just a little shorter than 1 complete turn around the diameter of the cylinder. Gently push the brushes into their holders while sliding the paper cylinder down to hold the brushes out. Slide the metal cylinder down the inside and pull out the paper. Voila! It took a while to figure this one out.

These were for cars where a mechanical tach drive wasn't available. Corvettes of the period had a mechanical tach drive connection out the back of the generator. I think it should be fairly simple now to cobble together a couple of electronic chips that would take the pulsing voltage from the coil hot lead, clamp the spikes, square it up, and divide by eight (or is it four?) and use that to drive one of these old electro-mechanical tachs. Of course, as mentioned above, any modern tach would be a much simpler solution. But, as it happens, I need one of these pulse circuits for my Indy car project because the '50s tach has the right rpm range and gauge face for me. I've never found a commercially available plug/socket that matches the Stewart-Warner one on the tach. Maybe I need to look at some old tube sockets.

[PackardV8]

the '50s tach has the right rpm range and gauge face for me.

Hi, Gary,

Do you have the tach you need? IIRC, one of those I have is a 0-4,500 classic model.

jack vines

[bezhawk]

What looks like a huge add on to the Tach head unit is exactly what Gary says.....an electric motor that moves the needle. It has to have the seperate unit on the distributor to send the pulses to the head unit.

[jrlemke]

Thanks everyone, I think I'll pass on the dash parts. I have several tachs I can use that don't look too out of place, except to someone who knows Studes. Thanks again. -Jim

[Swiss-Goldenhawk]

[QUOTE=garyash;843301]The three wires connected to the brushes lead out to a short cable with a strange 3-prong plug which looks a little like the base of an old octal radio tube. A mating connector on a long cable carries the voltage to the tach housing.

Hello, I am looking for this mating connector with the long cable that plugs together with the sending unit. I already have the sending unit pictured above, but I am looking for the long tach cable needed. Are those reproduced or what would be the best thing to do? I can't seem to find such a cable at any vendor...

Thank you

Rudy (57 GH)

[BShaw]

If, like me, you feel absolutely compelled to disassemble the sender to see what's inside, then you can inspect the brushes. Do this on a large table where the little brush springs won't fly out of sight.

Now that it's mentioned, if anyone has any of the correct springs or knows the size/number PM me as I did not follow Gary's wise advise above a few years ago and my sender is still sitting unassembled in a coffee can on my work bench.

[Dads Baby]

When doing tasks like this, I like to use a large clear bag and put my project in it. That way if a part wants to fly it won't get too far!

[rkapteyn]

I have some of these cables with the three prong connectors both N.O.S. and used if I can find them in my 38.000 sq/ft building. I will put them on ebay when I find them.
Offers invited . I have senders , hold down clips , tachometer heads both for Hawks and Larks.
Robert Kapteyn.

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