I had hoped to assemble a set of four rebuildable coils to experience the sheer joy of driving my T as described by those of you who have coils in perfect working order. I've also been gathering the pieces needed to cobble together a hand cranked tester.
But based on what I'm reading with an ohm meter it seems that all of the 12 coils I've purchased and traded for in the past few months are dead and not easily rebuildable. I guess I need to bring a testing device with me when I go to car meets and flea markets. Now I have a great collection of book ends. Still running on the plastic coils ....
John Regan (Fun Projects) makes a coil checker that is easily carried to test coils and determine if they are good or bad.It is very reasonably priced.
Is that the one for around $30 that is specific to testing the primary winding?
Mark, why do you say they are not easily rebuildable? We are very fortunate to to have people like John Regan, Ron Patterson, and Brent Mize who are wizards when it comes to T coils. I'm sure anyone of them could get you squared away with some nice coils. Look into it, you won't be disappointed.
Sounds like you now have the perfect number of coils to rebuild.
Simply heat the tar out into an old pan and you'll be ready to install the new parts and repot the tar.
That's when the fun starts after you get your HCCT rebuilt or for perfection one of Mike Kossor's ECCT's.
Then you'll have your sweet humming coils and some spares to sell or trade with your friends.
About the only thing that you can test with a simple tester like an ohmmeter (I love my volt/ohm meter!!!) is the general continuity of the primary and secondary coils or maybe the points connections.
Some years ago, I acquired about twenty coils over the course of a few years with plans to properly set up a few model Ts. One day I decided to test them all and found about 2/3 of them failed continuity. I managed to put together two sets. Several years later, I started wanting more coils for a couple more Ts. So I got my box of failed coils and checked them all over more closely. Upon carefully taking them apart, and inspecting and checking better, I discovered about half the failed coils had simple broken connections inside. The actual coils inside were okay. With a little soldering, I got a little over two more sets of four out of them. Three coils had shown failures for nothing more than a contact failure between the inside wire and outside contact button itself.
So, chin up! You may yet have enough rebuild-able coils for one T.
Mark, John Regan's coil tester is handy (I have one!), but really only tests the Secondary windings. Those are fine wire and more prone to breakage than the primary windings. Just because the secondary tests out OK, doesn't mean there isn't something else wrong with the coil boxes.
Mark I have a hard time believing that you could find that many bad coils in one place. I would expect maybe one out of 12 to be bad windings. Maybe re- examine your technique?
Here's my technique. I pull the coils out and call Brent Mise. I've never had to touch a coil since. Reminds me to order a new set for the new car.
I'm about in Mark's boat in that I find coils here & there. That is no large amounts at once. Found & repaired about 25 or so and as Royce said about finding coils not one of them has been a total bust. Your testing methods must be at fault. I'm not saying impossible just not likely. Sounds like you want to learn & do your own so do some reading & ask questions.
I find it interesting that this post finds electro-mechanical induction coils a mystery.
I've never looked but there might be a simple set of Go-Nogo tests. Like a logic tree for instance. Can someone list the proper readings? I think Mark could use it.
In my experience the primary is just rarely at fault except where there has been obvious tampering of the coil. The primary is heavy wire and I buy hundreds of old coils by "beeping" the secondary and I just don't bother to check the primary since I am pulling the entire winding out of the box and will place it in an all new box after I hipot test the windings for issues between primary and secondary and primary to core. That hipot test rarely finds anything but I do it because it is just way to hard to pull the winding back out of a new box at the finish line when it has been cut out, glued, sanded, sealed, stamped with trademark and fully adjusted. The "Coil Beeper" checks the secondary for too high of resistance and too low of resistance and only beeps if the coil falls into the window of being OK. For you guys the box condition is important so you want to make sure the coil is rebuildable by checking the box first. I don't care if the box is even there. I care only about the winding but have the same concerns for them to be OK. I carry my beeper in the door pocket of my truck so I always have it handy because T coils can be found literally ANYWHERE!!! Ford made 60 million of them.
The first time you do NOT buy a box full of coils that someone has "cherry picked" the coil beeper will have paid for itself. I went through a batch of coils that I bought at Chicasha and out of 300 not a single coil that "beeped" had an issue with the primary. It just doesn't happen enough for me to even care about it so long as final testing proves it out.
I made the thing for my own use only but had so many people ask "what is that thing doing" when they heard me "beep-beep-beeping" through a box of swap meet coils. And when I told them what it was they asked where I got it soooooooo.....
Here's a drawing from Ron Patterson that will help you check coil resistance Mark. Clean the three button connections so you have good electrical contact there.
As you use the word, "despondent," I'm going to assume you're sufficiently weary of dealing with your coil problem that you'd like to get it fixed, done and over with as expeditiously as possible. _To that decisive end, I'd suggest you get in touch with one of these reputable craftsmen and have him slam-dunk the problem once and for all:
407 Stonegate Drive
Phone 859 881-1677
Model T Ford Ignition Coils, Generators and Starters rebuilt and tested.
6498 Flaxton Ct.
Model T coils repaired
When I think "despondent", I think of someone with the barrel in their mouth and their finger on the trigger.
Perhaps "annoyed", "weary", "tired of ..", "frustrated" might be more apres peau ?
Disirregardlessly, there are plenty of easy solutions to coil problems.
Question for the experts - From the diagram presented by Garnet, is it possible to check the capacitor between D - E? Provided the points are open.
YES! that is exactly how you do it.
Question: I have a coil that I put a new cap in (orange). I get no reading at all between A and B. The coil fires and will throw a spark almost 1/2". What's going on?
KW by the way.
The secondary is open, but still working (for now).