what is the easiest way to tell if a coil is rebuildable? I need to get some done and want to start with good cores.

Don
Check the secondary winding. If good there is a 90% chance it can be rebuilt. If not the coil is firewood.
Ron the Coilman

But remove the tar before you burn the wood!

how does one check the secondary windings?

Put an ohm meter across the two side terminals (Spark plug and timer terminals). It should read somewhere in the neighborhood of 3200 ohms. Some may be different. The main thing is that they not be open across those two terminals.

See

http://www.mtfca.com/discus/messages/179374/210199.html

Dave

If the secondary is bad why not replace it with one of the reproduction secondaries?

It's easier to find a rebuildable coil for $5.

(Not outside the states it's not)

I stand corrected.

or even in Missouri

There's allot of BTU's in that thar tar.

And the copper wire will add pretty colors to the flame!

BTU's ... British Tar Units ????

Garnet

So what are you guys offering for coils with bad secondaries?

Probably burn about as long as a "presto log".

Also, there may be parts on a coil with bad secondary windings that would be worth saving. Sometimes even a wood side can be used on a coil of the same vintage.

If the cases are bad and they have continuity I normally can get 3.50 for them, if no continuity they are junk, not rebuildable, so says John Regan

I agree. One day I might change my mind, but right now, it's not worth my while to swap windings out in a coil. I toss 'em if they are bad. I do have a couple of exceptions that the wood was so very nice, that I put them on the shelf.

Why toss them when you can sell them on ebay as rare Model t coils that are highly collectable. Hmmmm.....$50?? Has to be a bargain.

Gotta sleep at night. 'Course, it don't seem to bother some folks.