Electrical: '54 Commander - How do the start switch and solenoid work?

[northern]

I'm part way through rewiring the Commander Starliner. It already was converted to 12 volts negative ground before I tore out the old cloth covered wire and started fresh. It has a three terminal solenoid mounted on the inner fender, near the battery. As I'm working my way through the rewire, I'm trying to make sense out of how everything works.

This car has a toggle start switch on the dash; the switch is separate from the keyed ignition switch. The start switch and its connection to the solenoid has me scratching my head. Most solenoids that I have seen work by sending 12 volts to the small third terminal when one turns the key to the start position. That closes a switch in the solenoid that sends 12 volts through to the large cable to the starter.

On this Studebaker, the small third post on the solenoid is hot or energized all the time. A single wire runs from that small post to the start switch on the dash (through the neutral safety switch). The start switch on the dash only has one terminal - the terminal that connects to the solenoid small terminal.

Can anyone tell me if this switch/solenoid combination works by grounding the hot wire from the solenoid to the car body? This sounds a bit crazy to me, but that's about the only explanation that I can think of at this point.

[brngarage]

Yes. the starter switch on the dash grounds the small terminal on the starter solenoid. This completes the circuit from the battery cable side of the solenoid to the starter side and the starter cranks the engine.

[northern]

Glad to hear that I'm not going crazy. But it still does not really make sense to me, and it seems backwards to how newer solenoids work. (This sounds slightly similar to how one shuts off a dirt bike, by pushing the kill button, thereby grounding out the spark.)

Grounding the small hot terminal must close a switch in the solenoid, thereby allowing power to flow between the two large terminals on the solenoid. How long did Studebaker use this method of grounding the solenoid third terminal instead of energizing it to activate the starter?

[StudeRich]

You are correct, that system would be from the 1930's until 1955 for 6 Volt Positive Ground Cars, WITHOUT a "Key Starter" Switch and 12 Volts.

The 12 Volt Cars require a second small (I) Terminal on the Solenoid for the 12 volt boost wire to the Dist. for starting in "Start" position, in addition to the ("S") Terminal and wire to the "Start" Position of the Ign. Sw.
When in the "Run" position of a Key Start Ignition Switch, the Coil runs on a wire from the Ign. Switch "Ign." Terminal to a Firewall mounted Resister and sends 8-9 Volts or so from there to the Coil (+) Term.

You will need to ditch the 6 Volt Type Solenoid and Ign. Switch and the grounding Start Switch when going to 12 Volts. It is a Standard same as Ford 12 Volt Solenoid.

A Shop Manual with wiring diagrams for '56 to '64 Cars would be a good thing to have but there are Studebaker Wiring Diagrams on line at Bob Johnstone's Site and Chuck Collins Studebaker Parts online Website.

[KCoupeNewbie]

I'm not as far along as Northern with my '53 K coupe project, so this thread is really an eye-opener when it comes to the solenoid circuit; when I got to the same point as Northern , I too would have thought I was crazy.
So thanks brngarage and StudeRich for your responses.

Which raises a question: if we want to eliminate the single terminal starter swith and go with a normally open, 2 terminal switch: is there, in Studeland, an appropriate spring loaded (momentary) switch that would install in the '53/'54 dash and look like it belongs?

Thanks to all you experienced hands who make this forum so helpful to the new guys.

Coker Golden

[northern]

Rich, I understand what you are saying, more or less. Please bear with me as I sort through this.

But - the car was previously converted to 12 volts negative, and it starts and runs well with the old style three terminal solenoid and the grounding toggle switch on the dash. The coil feeds from a separate coil wire; that one goes to a ceramic firewall mounted resistor and from there to the coil.

Unless there is some reason to change the present set up, I would prefer to leave it as is. It is nice to be able to use the original start switch on the dash - it's a great looking switch.

Another challenge I have is deciding what to do with the heater/air and defrost motors. They are 6 volt but do not work - maybe a previous owner fried them by hitting them with 12 volts. Of course I could look for replacement 6 volt motors and then use a voltage reducer to run them, but I would prefer to eliminate the voltage reducer. Does anyone rebuild and convert those motors over to 12 volts? Or is there a source for new 12 volt motors that fit?

[mmagic]

4 pole starter solinoid... NAPA number ECH ST81.. $23.20. Just bought one last week.

[Dick Steinkamp]

Another challenge I have is deciding what to do with the heater/air and defrost motors. They are 6 volt but do not work - maybe a previous owner fried them by hitting them with 12 volts. Of course I could look for replacement 6 volt motors and then use a voltage reducer to run them, but I would prefer to eliminate the voltage reducer. Does anyone rebuild and convert those motors over to 12 volts? Or is there a source for new 12 volt motors that fit?

Get the heater and defroster motors out of a 56-62 C/K. They are 12V and the same form, fit and function as the earlier ones. Same with the wiper motor (wiper motor up to 64)

[Dick Steinkamp]

4 pole starter solinoid... NAPA number ECH ST81.. $23.20. Just bought one last week.

I think the problem with those for northern's application is that the present 6V one makes the connection by grounding the terminal on the relay and the later 12V ones make the connection by putting 12V to the start terminal on the relay.

Electricity is magic to me, but is there a way for him to use his current one terminal, momentary on switch to activate a 12V starter relay?

[brngarage]

I am using the original starter toggle switch on the dash in my '53 Commander (I like the look of it). What I did is keep the original solenoid and trigger it by the dash switch, I am using the "output terminal" of the original solenoid to feed the "trigger" terminal on a 12V solenoid and using the 12V solenoid to start the engine and supply the 12 volts directly to the coil while cranking (with a resistor in the "running" circuit to the coil). Seems to work just fine. I suppose I could have used a relay rather than the 6V solenoid, but I had it and it works.

[StudeRich]

I think the problem with those for northern's application is that the present 6V one makes the connection by grounding the terminal on the relay and the later 12V ones make the connection by putting 12V to the start terminal on the relay.

Electricity is magic to me, but is there a way for him to use his current one terminal, momentary on switch to activate a 12V starter relay?

Anything CAN be done. You could isolate the switch from ground with insulator board, solder a wire to the Starter Switch housing or use a Ring Wire Terminal (Eye) under the switch mounting, fastening Nut, insulate the Hole in the dash and run it to the Ignition Switch Batt. Term.

This would have to be done very carefully, if any part of the "HOT" Housing touches ground, you WILL have smoke!

This makes for one really strange switch that will really confuse someone else down the line!

Northern, what they forgot is the 12 Volt Start "Boost" function, so you are starting with the Resister reduced voltage, which may cause problems if you use some types of Electronic Ignition Systems.

Whatever you do, or do not do, please put a two legged plug-in, Fuse Holder and 30-40 Amp. Fuse in the Main Power Feed wire from the Solenoid to the Ammeter and or Ign. Sw. which will protect the entire Car from any short circuits anywhere except the Horn Circuit.

[mmagic]

3 wire solinoid Negative ground ---
02 (large wire from the battery) (+)
02 (Large wire to the starter) (+)
14 small wire from ignition start pole (+)
Base of unit grounds to the body

When current (+) from ign start pole occurs it completes a circuit to the Ground (-) from base of unit activating the solinoid. This closes the connection of wire from battery and wire to starter.

On 4 post solinoid activating the solinoid also closes a connection between battery and small pole that connects to the coil to provide initial start charge to the coil. On vehicles with three post solinoids another method is found to provide kick start power to the coil. On a 4 pole, using an ohm meter touch the ground (base) and small poles to identify the small pole that has resistance... that pole is the trigger. The other small pole should be wired to the coil plus.

[StudeRich]

The issue of how the early 6 Volt System works vs. the newer 12 Volt System, has been solved back in Post #4, the current issue now is, how to solve this one:

Quote northern: "Unless there is some reason to change the present set up, I would prefer to leave it as is. It is nice to be able to use the original start switch on the dash - it's a great looking switch." Unquote.
(While using the 12 Volt non-Key Start System).

[mmagic]

Stick a relay on the line.
Poll 86 -- (-) Ground from dash switch--- Source ground that completes the circuit with 85 to fire the switch internal to the relay
Poll 30 -- (+) in from ignition on--- Source of power to be sent to 87
Poll 85 -- (+) in from ignition on--- Source power to the switch internal to the relay
Poll 87 -- (+) out power from 30 fired by the switch--- power out to the starter solinoid
Poll 87a -- (+) output when 87 is not hot... not used in this case.

Don't be intimidated by relays.. they are handy for things like this or where you want to use low amperage to control a high amperage item like headlights. I like (NAPA) AR143 for up to a 20 amp relay that has a tab you can screw to the firewall. EC 23 is a socket with pigtails that is easy to work with or you can just crimp spade ends on lead wire. Don't know where they came up with the poll numbers but they are used on all relays. Relays identified as NO are normally open and NC are normally closed.

[Dick Steinkamp]

Stick a relay on the line.
Poll 86 -- (-) Ground from dash switch--- Source ground that completes the circuit with 85 to fire the switch internal to the relay
Poll 30 -- (+) in from ignition on--- Source of power to be sent to 87
Poll 85 -- (+) in from ignition on--- Source power to the switch internal to the relay
Poll 87 -- (+) out power from 30 fired by the switch--- power out to the starter solinoid
Poll 87a -- (+) output when 87 is not hot... not used in this case.

Don't be intimidated by relays.. they are handy for things like this or where you want to use low amperage to control a high amperage item like headlights. I like (NAPA) AR143 for up to a 20 amp relay that has a tab you can screw to the firewall. EC 23 is a socket with pigtails that is easy to work with or you can just crimp spade ends on lead wire. Don't know where they came up with the poll numbers but they are used on all relays. Relays identified as NO are normally open and NC are normally closed.

That is a great idea, and the little cube relay could be hidden most anywhere to maintain stock appearance.