Repairing Plastic Coils

[Harry Lillo]

There have been some comments in the Classifieds about re-building plastic coils. I am starting a new thread on this.
In particular, has anyone successfully opened them up and replaced the capacitors in plastic boxed coils?
If so, how did you get the "lid" open? We have tried to pry them open but distorted the case.
Right now our local coil builder has a set with the capacitors mounted outside the case. This means the old capacitors inside the case as well as the external capacitor are contributing to the function of the units.
They test well but we are not sure about life?
Any experience from others is appreciated.
Harry Lillo
Calgary

[TWrenn]

Been like forever since I had a set of plastic coils, which only worked nominally well. So not being an expert I'll just say as I recall the makeup of the "shell", I'd be betting it would be pretty problematic "opening em up" and doing your thing with them and then especially getting them back together neat and tidy. Maybe I'm wrong. I'd stick with the good old wooden ones myself.

[Moxie26]

Instead of sliding down the side of a wood coil after you remove the two bottom nails, the plastic coil has the same side to open but has to be pried gently off since it will be adhering to the tar innards. Plastic coils usually ran smaller capacitors up in that left upper quadrant.... So for removal you would have to concentrate in that area till you find the old capacitor remove and possibly dig out a little bit more tar to fit your new capacitor inside. Working with clean shiny wires with good twist connections, finished with solder and then placing the new capacitor in the confines of that coil and then finished off with some hot tar would be the beginning of finishing off with a new set of points and proper electronic calibration.

[JohnH]

The lid is held in place with the tar alone, so it’s easily prised off with a putty knife. The condenser needs to be replaced since it’s the wrong type, being too low in value, and not of the high dv/dt type required. I reattach the lid with silicone. The electrical characteristics of these coils is slightly different to the wooden ones, but they seem to set up without any problems on the ECCT.

[Quickm007]

Hi Harry, Hope you doing well. Sometimes when the plastic is not solder or bond to the case, I use a C clamp to distort the case itself and I'm able to removed one side with a flat tiny tool. After you dig carefully in the tar and you have access to the capacitor. Replace it, heat the tar again and put it back. Replace spring or other parts when is required after adjust the coil. I really like Mike Kossor ECCT for adjusting coils. Hope these little insights help. All the best. P.S. Capacitor at Lang's work well.

[Moxie26]

Mario, John & Tim .... Good points !

[Harry Lillo]

Thank you everyone for sharing your experiences.
We will exercise more patience in trying to open the cases.
Most re-builds are with wood boxes. After a while a few plastic
cases pile up and it would be nice to use them rather than tossing them
We have access to a different testers including ECCT, HCCT and
electronic testers.
Harry

[Moxie26]

Harry, even more good news is that the hcct tester will give you a basic reading of 1.3 amp during adjustment, ..........the ECCT will give you a more precise reading, and the same reading for all four coils so each coil will fire off with the same energy at the same firing time ,... And in my experience would give you a better running engine