Mag coil ring question

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Model T Ford Forum: Forum 2015: Mag coil ring question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Tuesday, October 06, 2015 - 07:39 pm:

I recently bought an engine which someone else had rebuilt. I got it running on a 12-v battery, but it didn't run at all on mag. I tried to do an in-car recharge of the magnets, which I have done several times with good results. I set it all up with three 12-v batteries in series, per the drawing in the MTFCA Electrical book, as always. But I didn't get a spark at all when I grounded the cable to charge the magnets. I checked the mag post, and it looks good. Does this mean that the coil ring has an open somewhere?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Mikeska, Denver CO on Tuesday, October 06, 2015 - 07:52 pm:

Mike,

Use your Simpson meter on the ohm scale and touch one lead of the meter to the mag post and the other to a good frame ground. It should show almost no resistance (direct short) If there is no reading the mag is open. Note that you need to verify that the mag post is connected to the mag ring.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Tuesday, October 06, 2015 - 08:14 pm:

Good idea, Paul. Thanks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Thursday, October 08, 2015 - 09:27 pm:

OK then, here is an update. I'm not trying to dominate the forum with my concerns, but I think that when a successful outcome is achieved, it might help someone else who encounters a similar problem.

I did as Paul suggested and tested the mag coil through the mag post. Nada. Then I removed the mag post and did the test directly to the mag ring contact. There was some continuity, depending upon where the probe was placed on the contact. So I figured that there must be something on that top contact which was preventing continuity. I took a die grinder stone and worked it by hand on the mag contact, trying to remove whatever was the problem. This took several tries, but it eventually led to good readings with my Simpson meter. The spring-loaded mag post (one for an outside oiler) by itself read good for continuity, both extended and compressed. But when I put it in place on the hogshead, there was no continuity. Finally I tried another new oil line mag post, which I had in stock. It worked perfectly!

This was a head-scratcher for sure, taking up the better part of two days tracking down the problem. I still don't understand what happened, but now the car runs on mag and there is joy in Mudville. I didn't even need to charge the magnets! Good clean living pays off again! :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary Tillstrom 30 miles N of Memphis TN on Thursday, October 08, 2015 - 09:39 pm:

As far as the oil line, if you want something that works well without pulling the hogshead, try the Bendix cover oiler mod. It pumps a ton of oil to the front and is easy to do.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, October 08, 2015 - 09:57 pm:

Some of those mag post oilers the contact is not long enough. A fix for this is to put some fiber washers inside between the top of the post and the threaded contact to lower it a little, however, be sure not to block the oil passage. If the hogs head is off the car, some solder can be added to the contact at the top of the magneto coil, but not worth pulling the hogs head just for that purpose. Your problem is solved. Good for you.

Have fun driving your T.
Norm


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