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I have noticed that the ignition coil on my 1929 Super 8 has a armored cable that goes from the dash board to the bottom of the coil. Is there any guide when one has to replace the coil? Are new coils of that type availale for purchase anywhere?

Thanks in advance,

Rick M
'39 Super 8

From your title and first line query not sure if you are asking about a 29 or 39 coil but will go with 39 from your other post. Max Merritt lists having certain coils available for each year and to inquire if yours is not specifically listed. Kanter might too but just like the 41-7 Clipper coils with armored cable connections, they are expensive. Unknown if rebuilt or NOS but when it comes to NOS I would be cautious about putting a 75 year old electrical component into service. Rebuilts also do not have the greatest fan base so guess it is a tossup.

Don't believe there is a hard and fast guide but on Clippers the usual symptom of a failing coil is it starts acting up when hot to the point of complete failure and then when it cools down all is well again until the next time. Eventually it seems to totally fail or leave a person stranded once too often and gets changed. A faulty capacitor can also exhibit the same symptom so that too is a change item.

Coil tests are notoriously unreliable indicators of a coils condition. Best bet is to just go by your driving experience, typically they will begin to show failure when they perform OK when cold and you begin to get intermittent ignition breakup when they get hot.

Though the twin coils for the 33/34 Eights and Super Eights and all the Twelves are reproduced in excellent quality I'm not aware of any exact reproduction of your coil, and NOS coils would be questionable after all these years. Just to be safe when touring, carry a universal 6-volt coil in your tool box which you can always rig up in an emergency - you can just hot feed it via a jumper from the battery or starter post and avoid having to remove the old one and the armored cable to get the power feed. I've done this on the road a few times over the years for folks who have had a coil failure, it makes matters simplier to have some duct tape and just tape the emergency coil to the side of the existing coil.

The best means of testing a coil is with an oscilloscope. If the coil is internally shorted it will show up in the section after the spark line. The waveform will not oscillate properly or will show negative voltage. A good old fashioned adjustable spark tester from NAPA should show 20-25kv ignition voltage. If it shows any intermittency then there is an ignition problem.

You can also test the coil on the road by hooking a scope up to the primary and looking at that waveform. If it breaks up under load there is an ignition problem.

The armored cable and ignition switches on those cars are notorious trouble makers because they short circuit. So if you suspect a problem bypass the whole system with test parts and check vehicle performance.

Good reminder by Tim, if you don't know that the hot lead inside the armored cable has been changed, do it now. Chances are the insulation is crumbling off and possibly even shorting out. You wouldn't be the first to diagnose a faulty coil when in fact it was the failure of the insulation on the wire inside the armored cable.

Opps! Errant fingers here. A 1939 coil is what I am asking about. I will follow the advice and have a generic 6 volt coil handy in the event the coil in my car is not working. I will need to do a bit of research to see the proper way to wire it in since it has been 40+ years since I had a car with an old coil and points iginition.

Thank you all for the information.

Rick M

For what it is worth, I've taken the guts out of an old, original Autolite coil body and slid a new, generic coil into it. Since the original Autolite has the rear mounted HOT ignition line coming into it, I ran a wire from the front terminal around the hidden side of the coil, back into the body of the Autolite can, then to the rear ignition cable.
If someone looks closely, they could tell, but I am happy with my result. Especially, since it would be easy to replace with another modern coil if ever needed. Currently, I have an original on the car that has been working for almost 20years, but created the dummy as a spare.

Regarding the jacketed ignition cable, also called 'armored', 'conduit', Tim is correct that the combination of the old lacquered cloth insulation and the difficulty to access the wire inside the jacket results in a likelihood to fail. I've repaired several of these by carefully opening up the interface between the switch body and the jacket. This allows for inspection and cleaning of the switch contacts and replacement of the ignition wire from contacts down to the coil.

Hope this helps,
Pat

Pat, what you've done is, I suspect, along the same lines as the commercial suppliers of "new" dual coil assemblies for the 33/34 Northeast units on Eight and Super Eights, and the 32-39 Twelves. In these coils (original pictured) the high tension lead does not go into a conventional "tower" but rather mounts under a stud and nut in a horizontal alignment and then covered with a decorative cap with acorn nuts. The hot lead from the ignition is at the bottom and either of the two studs at the top is suitable for connecting to the points. The lead for the shielded wire from the ignition switch is a threaded stud at the base of the coil, accessed when the lower cover plate is removed from the aluminum housing into which the coils are inserted.

When I remove the decorative cover from the reproduction coils the high tension lead is connected to a conventional "tower" down inside the canister. Those reproduction Northeast coils, while not inexpensive, are beautifully executed to match the OEMs in external appearance.

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Pat,
Thank you!

Rick