Coil Box Mounted Switch - What To Improve?

[Hudson29]

A couple of weeks ago I had prepared the '14 Touring for another test drive. I had done all sorts of tinkering and wanted to get another flush through the cooling system. It was completely ready to go, oil cups filled and I was looking forward to the outing. It would not start. It ALWAYS starts, but not today. The '18 motor turned over on the starter but no fire, not even a pop.

My schedule was full and "Ole Rough & Ready," the '23 Runabout was pressed into service to go to that car show in a neighboring town the following weekend.

This past weekend I pulled the coil box out of the '14 and had a look at the switch. It all looks OK to me. It moves easily and seems to have good mechanical contacts as far as I can see. I'm not sure how to use the meter to check electrical connections, it probably has a continuity check someplace but I don't know how to set it for that. I can check battery voltage so possibly a battery might be used to check it that way.

What can be done now while it is apart to make sure it is in good shape for the next 110 years?

Paul

[TRDxB2]

Not sure why you jumped to suspect the switch without first checking continuity to the to the BAT & MAG posts on the coil box. If they proved correct then no need to take your switch apart. If no continuity then potentially wires within the coil box

The best way to diagnose electrical issues is to break up the circuit in smaller runs. (switch to posts; post to spark plug etc) .

[rickd]

I use the Ohm meter on my multimeter for continuity checks. Continuity is no resistance to the flow of electricity. While you have your coil box and switch apart it would be a good time to rewire everything and then check the continuity of all of your connections. Then you know things are ready to go.

[rickd]

Paul, you probably know all of this stuff but this is the coil box wiring diagram I used on a Fun Projects rebuild. Found it useful for the continuity checks. Ignore my notes on the diagram that how I work when I do this stuff.

[Steve Jelf]

You can test the switch without opening it. With the switch turned to BAT touch one lead of your tester to the battery terminal on the back of the box and the other lead to the power strip across the inside bottom of the box. If current flows between those points, you're good to go. Switch to MAG. Do the same test between the magneto terminal and the strip. Current getting through? Yes? Fine. With the switch set to OFF do the same two tests. No current getting through? Switch OK.

[Original Smith]

You may wish to put in a new white rubber strip on the back side. I don't know if Lang's has them or not? We used to get them from McMaster Carr.

[TRDxB2]

You may wish to put in a new white rubber strip on the back side. I don't know if Lang's has them or not? We used to get them from McMaster Carr.

Lang's has it but author of post may not. Shows only 4730G

[Hudson29]

Thanks for your help here. The switch is just one part of a general freshening up of the ignition system. I have a plastic wood kit that I'm currently working on and will install new ignition wires and hopefully, new wires to the timer also.

Not knowing how to test the circuits I decided to take it apart & look at things. There is a mechanical part to electrical systems & my eyes might spot a loose terminal, frayed wire or broken or weak spring. I found nothing like that, it all looks sweet.

I had not thought to use the ohm part of the meter to test for continuity but will read the meter instructions about how to set it for this. I do know that even if the meter shows no problems at the time it makes the test, that does not mean that the problem can not come back while the car is vibrating & bouncing down the road.

Paul

[Hudson29]

Thanks also for the gasket info. The paper gasket is there and in good shape but the arced flexible one was missing & I had no idea about it. I'll see if I can get one on order.

Paul

[Jerry VanOoteghem]

For continuity, set your dial here. The meter will give an audible "beep" for a circuit with continuity.

[Lil Teezy]

Those are beautiful mechanisms and it seems like yours is in very good shape and already very clean. As per your initial post though, I labeled and described what I would do to any type of switch like it from the same period.
With extremely judicious use of these products and an extremely gentle approach to the repairs it will be usable far into the future. Apply the tiniest amount of glue and wipe off any excess and plug the holes with something to ensure no glue makes it into the threads. Let it sit overnight. Use less than a drop of oil on the rotating assembly with a probe and wipe it off thoroughly after some rotation either way. Polish the brass face and use just a thin strip of emery cloth to polish the inside of the folded contacts. Swab with alcohol or other cleaner that leaves no residue. Put the tiniest drop of grease on the slider and wipe off any excess. The new paper gasket will likely benefit from some light sanding with an emory board as any ill fitment could crack the covers when tightened. Double check that the wire cover is intact and no contact is being made where there’s rubbing. Clean the threaded inserts with a swab and some penetrating oil and remove any excess. Remove, clean and re-tighten to snug all the fasteners and then “send it”. Any disagreements with this advise or more specific treatment would be most educational as I’ve never actually owned a coil box switch like this. Just basic service methods for continued use of any mechanism of its age as I learned it, hope this helps. -Chris in Boulder

[Hudson29]

Thanks Jerry for your advice on setting the meter. With it, I was able to test the new coil box bottom and then the switch itself. I'll keep that meter on the workbench to test the coil box build as it goes and then when ready to install test the bottom strip with the BAT & MAG posts as Steve suggested.

Chris, thanks for the tips on improving the switch. The wires will be the new 18 gauge ones supplied in the plastic wood kit. The cracks in the mounting screw bosses looked dangerous and I'll be glad to reinforce them.

Paul

[lcleeton]

My experience with the switch. I have a '14 Touring and rebuilt my coil box. I also cleaned the switch and put in new wiring. One thing I found while rebuilding was the copper fingers in the box that touch the contacts on the coils had been changed by probably decades of prying/bending them out to make better contact. The copper had lost its springiness. Is that called work hardening? They wouldn't stay firmly in contact with the coils. I replaced them with the available reproductions. It's better now. Later after running my car quite a bit, I developed a symptom where under heavy load at moderate RPM, the ignition would randomly completely cut out and then come back. This resulted in a bad backfire and even once splitting open my muffler. After a lot of troubleshooting, I discovered that the ignition switch contacts had the same situation that I saw with the fingers in the box. I could squeeze the clamp parts to make them tight, but they would just open back up when actuating the switch. I bought the available reproduction switch and put it on the box. The new switch is obviously more secure in staying on and not losing contact under vibration. No issues since.