Ignition coil measurements

[MikeC5]

Anyone know what the primary and secondary resistane values should be for a '25 coil?

[platt-deutsch]

Primary 4.9 ohms

Sec. 3.8k

I rebuild these for Meyers and Romar. Rebuilt looks exactly like the original.

A ohm reading wont really tell much about the coil because if even one turn on the secondary has a short it will kill the output. There is 12,000 turns on the secondary. I rewind them and encapsulate the coil in 2 part epoxy resin.

Edited April 16, 2011 by platt-deutsch (see edit history)

[idrjoe_sandiego]

PD- a couple of questions for you? Do you have the same info for a 29 DA coil? Do you rebuild these as well? Have you ever measured the operating temp of these coils? Mine seems a bit hot, but I haven't gotten the gun out to actually measure it. I understand that the epoxy filled coils are great for vibration, but the oil filled are best to run cooler? Any thoughts? Thx, Joe.

[platt-deutsch]

The Dodge coils I have built so far are the 12 volt and the 6 volt that looks identical. I dont know about the 29 coil. I would have to see one or at least a picture of it.

As the 25 coils that I am familiar with are not in a metal can I cant fill them with oil. They seem to run cool. I have ran them on test for hours with out getting too hot. The original coils used a varnish coated wire and now we use polythermaleze coating that is good for about 400 deg. F. The old varnish got brittle and cracked with age and so most of the originals have failed because moisture got into them..

[Guest 1930]

I think that I was supposed to send you one some time ago, every once in a while I think of it and then forget to check with you, if you dont mind I would like to send you one and this time I will mail it. If you are still interested than you can e-mail me your address at jhason2@yahoo.com Sorry if I did forget, I would like you to look one over

Edited April 17, 2011 by 1930 (see edit history)

[MikeC5]

Thanks. The coil is currently working but the insulation on the wires under the cover looks very deteriorated. I probably should have left it undisturbed...

[Guest 1930]

Mailed you 6 coils this A.M Gary, 5 DA and one DH. I believe that is what Keiser had told me that it was intended for.

I sent entire assy on the DH, key and all so you could see how everything works, I sent one DA in its entirety as well just in case there were internal differences. I made sure that the screws were lose between the coil and the switch, that is pot metal and it is very fragile so even when I set it down I do so slowly and carefully.

I would admit to knowing nothing ( practially anyway, I do have some literature ) about how to test these old coils, I dont know if you have ever posted an image here but if you can show me how you test them ( I learn best with pictures ) and also explain what has to be done than I personally would much appreciate it.

You will notice that one of the coils has no wear on the bakelite contact, that is supposedely N.O.S, I have two of them that came in boxes but the other did have wear so obviousely used and then put back in its box. You will see the wear at the contact switch portion. I know that just because it is N.O.S that does not mean it is any good and that is why it was sent.

If you decided to remove the switch be carefull since it has springs ect. As long as you remove it slowly though you wont have any problems, things dont just pop-out in other words.

If you can show me how to test them again that would be great. I have at least one other in my car that I would like to test and there are prob. others I need to dig out.

Edited April 18, 2011 by 1930 (see edit history)