The Stovebolt Site Forums The Shop Area The Electrical Bay Bench testing a 6V coil

I have 4 6V coils that I would like to bench test to see if they are good. How is this done? They are of the type that an electrolock cap goes on top of.

Rick

If you want something more effective than a simple resistance check of the windings, chuck a distributor in a vise, and use a battery and some primary wire to connect the coil like it would be in an ignition system. Then spin the distributor with a variable-speed drill motor clamped to the oil pump drive. The high voltage lead that would normally go to the center of the distributor cap should be able to jump a 3/8"-1/2" spark to ground every time the points break if the coil is good. Some coils don't spark well without a condenser in the circuit for some reason.
Jerry

A bench test may or may not verify whether a coil is good. Some coils which will read good while at room temperature, will not do the same once they reach operating temperature. A bench test is a good place to start, but may not pan out if the coil is on its way out.
Trial and error over time will weed out the weak ones. A new coil solves all of the guess work. They are not that expensive.

Who sells new 6V Electrolock coils?
Jerry

Nope- - - -that fits the top of a banjo-housing 4 cylinder Ford tractor engine. An "Electrolock" was an armored cable housing that fit the top of a mid-1930's coil on Chevy and Chrysler Corp. engines as an anti-theft device. I believe Model A Fords had the same setup. The wire from the ignition switch ran inside the armored jacket, and entered the coil from the opposite end than the high voltage tower and the primary terminal going to the distributor. Some electrolock systems had a coil with a flange that mounted through a hole in the firewall and put the whole ignition wiring setup inside the vehicle under the dash.
Jerry

The Model A had an armored cable that ran from the ignition switch to the distributor, not to the coil. The wires to the coil were not armored. One coil primary terminal was connected directly to battery power, the other to the ignition switch, and from the ignition switch to the distributor points.

The electrolock cap coil creates a problem for a replacement coil. One of the coils I have has 2 screws holding down the cap. I'm thinking of picking up a standard 6v coil, run the positive wire up the side of the coil and epoxy the electrolock cap on the bottom of the new coil.

Rick

That's one option, Rick. Another would be to make a short stepped-down adapter from aluminum for the "bottom" of a standard coil that could slip over the end of the coil and attach with a setscrew. Then the electrolock cable could be attached to the adapter with the original screws. That would be just a few minutes' work for anyone with a lathe. If you paint the adapter the same color as the coil, it would be hard to see.
Jerry

Oh, so I am expected to read someones ENTIRE post before I answer a question?
Sheesh, tough crowd. LOL.