Ungrounded Start Button for 1940 Ford

[Capuano]

I have changed my 1940 Ford Deluxe from 6 to 12 volts negative ground. The 12 volt starter relay has a grounded frame and the start terminal needs a 12 volt positive connection from the start button. The start button frame is grounded with only one terminal. I will need a start button with two terminals to supply 12 volts positive the stater relay. If that design is not available I guess I will need to put in a momentary toggle switch to supply the 12 volts to the starter relay unfortunately. Any suggestions would be appreciated.

 

[JSeery]

Ford used a two terminal starter button on the later pickups. Normally the single connection pushbuttons have a chrome button and the two connection ones have a black plastic button.

 

[Ross F-1]

Available at NAPA: Starter button (2-wire) ECH STB10
https://www.napaonline.com/en/search?text=ECH+STB10
They also have some fancier ones, with chrome button etc.

 

[Ken/Alabama]

You can get a starter solenoid just like the 6 volt one but for 12 volts. Everything stays the same but for the solenoid. Got one on my car.

 

[klawockvet]

I have a HAMB friendly 12V system with a high torque starter. The starter takes a constant battery connection to positive. I run a Standard product solenoid that works by grounding to negative from one post. I am using an original ford starter button and it works great.

 

[john in illinois]

I used this Cole-hersy 12v solenoid. Very good quality and works with one wire ground button.
Looks good too.


https://www.oreillyauto.com/detail/...ltage-regulators-20235/solenoid/24060/2622432

John

 

[fortyfords]

I kept the six volt solenoid and grounded starter button when I changed over to twelve volts. Works great and I like the button on the bottom of solenoid to bump over the engine when working on engine. The only bad thing about a grounded starter button is you have to be careful not to accidently hit the button when the car is in gear.

 

[Ross F-1]

...The only bad thing about a grounded starter button is you have to be careful not to accidently hit the button when the car is in gear.

Don't ever let kids sit in your car unattended!! They love to push buttons.

 

[38bill]

My 6V starter solenoid would not work when I changed over to 12V neg ground. I just added a simple relay that when grounded (through the original starter button) activates the new 12V neg ground solenoid. Under $10 and you don't need a super high amp model as all it does is active the solenoid switch.

 

[JSeery]

I have used the 24060 12v starter solenoid as well, here is the diagram if anyone is interested.

 

[Flathead Fever]

There is a 12V starter solenoid that is activated by a ground instead of positive. I have hundreds of old parts catalogs which I had organized but right now they are in a big pile on the floor, stacks and stacks of them, because I had to tear open the wall behind the cabinets they were in to upgrade my circuit breaker box in the garage. In the Standard Illustrated Parts Guide there are schematics' of all the different starter solenoids. There is one 12V solenoid that is controlled by a ground. I did a search and I found a YouTube video where the guy shows you the solenoid but he does not tell you what the part number is??? Here is the link to the video. I have a busy day. If I get time tonight I'll see if I can find that catalog and get you a number. I brought home all those over a 30-years period each time I updated them at work. There are parts and info in those catalogs you will never find anywhere else. Especially when you are looking for ways modify something. Try having the kid at Auto Zone try and find the solenoid you need for this project. The year and model of the vehicle is not going cut it.

https://www.youtube.com/watch?v=oaI2Lsb_-cg

 

[41Joe]

This is what I did on my 50 Lincoln, I isolated the solenoid from the body with plastic screws, washers and nuts. Then I put a wire from the battery side of the solenoid and attached it to the solenoid bracket. This way I could use my stock starter button. Although as someone mentioned before, the starter can be bumped over without any keyed power.

 

[JSeery]

Flathead Fever, that is what the 24060 is, a ground to activate. That is why I posted the diagram, so it would be clear. John also posted this information.

 

[Flathead Fever]

Flathead Fever, that is what the 24060 is, a ground to activate. That is why I posted the diagram, so it would be clear. John also posted this information.

Same solenoid as your 24060 here in the Standard book. SS-587, circuit #2, insulated base.


Circuit 7 is interesting. I only see one solenoid like this and it fits a '80-'87 Jeep. It has five-terminals and an insulated base (it must bolt to a plastic inner fender panel). I had one of these, an '86 CJ7's, I gave it to my daughter, it only has 23K original miles on it. I ran out of room in the garage. Keep the Jeep or get another Early Ford, Jeep lost out. I was thinking on this solenoid you could jump a wire from the battery terminal to the starter terminal. Then run a ground wire from the starter button to that rear ground terminal on the solenoid to activate it. The advantage to this would be having an ignition resistor bypass terminal for a hotter spark during cranking but it would not look as nice as the single wire solenoid.

Summit Racing sells the SS-587 for $29.00 and the SS-582 for $14.00.

 

[Capuano]

Thank you for the help! The Echlin Ignition starter push button switch ECH STB10 has two terminals which will address my issue which I have purchased. The only question now is how to connect the 2 wires. It has a female socket which may use the original Ford male wire nipple to connect the wire or some other connection type?????

 

[Capuano]

Reply to all. Thank you for all the helpful suggestions. I now have many alternatives to address the issue

 

[Flathead Fever]

Hook your old wire on the switch to one of the terminals of your new push button. Hook the other end of that wire to the "S" terminal on your new solenoid. Run a new second wire from your battery terminal on your solenoid to the second terminal on your push button. You can buy either male or female crimp on "bullet" connectors that plug into your switch if that is what it takes. Run all of these positive wires in insulation and through grommets where they go through metal! Standard products makes an asphalt coated wire insulation that looks appropriate for old cars (if you can find it). Ford used real small wires on the "S" and "I" terminals, my guess is they were 18 gauge. It would be a good idea to install a fuse or fusible link in the new wire coming from the battery terminal. We want the fuse to blow before the wire melts and starts a fire. I would think 10 amps would be an adequate size fuse but that is only a guess. I could not find any specs on the amperage draw of that solenoid. All of the circuits on a 12V Ford such as an early Mustangs get there power from that battery terminal on the solenoid. There should only be just the battery cable on the positive post. Here is a photo of a Mustang solenoid. You can see all the voltage positive feed wires are attached to that battery terminal on the solenoid.

When the engine cranks a full 12 volts goes from the "I" terminal to your coil which produces a hotter spark for starting. As soon as the engine starts and the solenoid disconnects the coil gets its power from the ignition switch which runs through a resistor to cut the voltage down which keeps your points and coil from burning up. If you buy a new 12V coil you need to know if it has an internal resistor or uses an external resistor? If it has an internal resistor you will not be using a separate resistor like the car originally came with. If it does not, you need to get the correct resistor designed for that coil. I buy chromed Mallory 12V coils and the external Mallory resistor that goes with them.

 

[1oldtimer]

Yup, use a insulated base solenoid. I used a Standard Ignition SS-587, also like described above it WILL crank with the key out of the car and in gear. To prevent this I used a Standard Ignition HR-116 under the dash, so now the ignition switch has to be on to crank the car.

Or you can go with a newer 2 wire switch (Standard Ignition SSB1) and a Standard Ignition SS-574 solenoid. Then wire the push button to the ignition switch, so it won't crank without the ignition on.