'48 starter question

[Trekster]

I have 2 '48 2 ton trucks that I (someday) will combine into one truck. I removed this starter from one of them and have never seen one like it. The relay looking thing has three terminals. One of the wires goes to the coil and the other two attach to each side of the distributor. When the starter pedal is pushed, the transfer bar moves a lever on the relay and it makes an audible click. My guess is it enables the truck to be started without a key but I am not sure how to turn the engine off. I could be way off also. Does anyone known what this is and what it does?

Thanks

[mr48chev]

Had the truck by chance been converted to 12 volt? That would serve as a resistor bypass switch if that was the case. Does the distributor have a governor on it? If it does that might explain the other two wires.

[Trekster]

Mr48chev, I don't think the truck was converted to 12 volts because the battery that was still in it was a 6 volt battery. I actually think you are correct in that it is resistor bypass. It also could have been converted and then someone put a 6 volt battery back in it. I don't think there was a governor but the truck was kind of stripped when I got it so who knows.

Thanks

[mr48chev]

The only other thing I can think of is that that switch is part of an add on piece of equipment that was used on that truck at one time.

This is where the past history of the truck would really help figure out what the switch was installed for. I just went through every page of the electrical section of the service manual and can't find any reference to that switch in the section.

You could always connect a loud horn to it with a hidden switch under the dash to break contact and use it as an anti theft device.

I did discover that although the conventional cab trucks used the foot starter forward control trucks used a solenoid. GM's way of saving a buck on the conventional cab trucks.

[Trekster]

I was thumbing through the Chev's of the 40s catalog and ran across a picture of the thing on my starter. It is a polarity reversing switch. The reversing switch reversed the flow of current through the points each time the truck was started. By reversing the flow it would cancel out the transfer of material from one side of the points to the other. Chevrolet used these from the early '40's to April of '48 which might explain why my other '48 does not have this switch.