I've just completed a batch of coils of which 8 was for a buddy that supplied me 8 cores. On inpection two of them where lighter than the rest and rattled somewhat. When controlling the capacitor on the Strobospark, the values where spot on and virtually no leak on the one and no readings on the second.
Here is what I found in the one with no readings:
My buddy had replaced the capacitor with the right type of orange drop capacitor, but not refilled the coil with tar.
After som driving, the one lead to the capacitor broke of fatigue and the capacitor did not do its job no more.
I replaced the capacitor with the flat ones so I could also reinsert the glass insulator which where also missing.
And just search for "type 3 steep roof tar" in these fora to find out why you should use tar and not some modern replacement.
100 million coils made with tar can't be a mistake :-)
Two reasons, maybe more, but for me the most important.
- first vibration, as you said before.
- second, by heating the tar over 100°C you get all the moisture out of the box and the system.
I just finished to rebuild 22 coils with new points, capacitors (the flat from FP or Lang) and rebuild boxes. Those 22 was what was repairable out of a pile of 26 coils. 4 had open secondary coils. Out of these 4 I take what I can, The wood, the bolts and nuts, the low tension coil and the most important: the tar.
Since I rebuild coils I always did it that way. I was never short of original tar.
With the wood I repair the broken boxes and I also rebuild boxes.
The good nuts and bolts are used to replace bad ones on good coils.
The low tension coils are used to replace the wiring during the rebuild of the coils. A few are used to replace the low tension coils as I need to rebuild Heinze coils.
The original low tension coil in the Heinze are unusable with the replacement high tension coils on the market or the normal Ford coils. There for I use the Ford coil and make it shorter.
In most of the Heinze coils is no tar but a brown stone like stuff. I replace it with the tar that I find in the normal coils. Till now I did a few and they work great but are expensive to rebuild.
a few more photos
Andre - looks marvelous. We are on the same page I will say. Except I do not deal with the older coils.
The most tricky is to take the box apart without destroying the finger connection.
The setting is different because there is no cushion spring in the contacts. About this it is al about the same.
Here is maybe a trick regarding taking out the tar - "bake" them 3-4 minutes in an electric table oven:
That softens the tar so it is easy to remove with a screwdriver or chisel for wood and to get the condenser out.
Only the upper heater is on - the lower will "tone" the wood in an unwanted darker tone (do not ask how I know).
And here is my setup for pouring the tar back in:
NO open flames to any of the tasks as I was warned about the fire hazard.
Andre: Any concerns regarding off gassing of corrosive acetic acid from the silicone material used to position the parts before pouring the tar? Not criticizing, just asking, I was cautioned against using RTV Silicone in such applications where corrosion of hardware components could cause problems.
Beautiful craftsmanship on your coil restorations! jb
James, I suspect that is hot melt glue Andre is using to secure parts before pouring tar. Hot melt tends to be a plastic base. Regards John
John is right.
I will take some photos tomorrow of the glue gun.
It is easy but you need to pay attention it is hot too.
For cleaning the wood I use sand paper aceton and cellulose paint thinner.
John, Andre: Thanks for that information. jb
As you can see I do not work alone There is always an assistant.