24 volt Coil Difference???????

oilleaker1 · Post by **oilleaker1** » Wed Oct 17, 2018 4:20 am

New issue cropped up. One of my friends recently discovered his M38 (Not A1) keeps burning his points in his 24 volt waterproof Autolite distributor with a original Autolite type coil. I've not had this . His is actually transferring metal or melting them shut. If he replaces them it runs perfect until it melts them again. He is using Echlin points and condenser from NAPA.

Would this be a condenser issue? Or are there 24 Autolite coils that are not internally resisted? If so his coil is not marked either way.

M37's, M38's, and M38a1's all use this coil in their waterproof distributors. Then there are the chrome Chi Com type coils which will or won't work well. They are a crap shoot. The Black aftermarket internal caps are junk also.

How do you know if the coil is causing this. My electrical knowledge is poor in this area.

I typed in a search and it came back no results. Anyway , if you've been down this road, what fixed the burned points problem???? Thanks, Oilly

skyjeep50 · Post by **skyjeep50** » Wed Oct 17, 2018 7:10 am

One thing to check first is to make sure he isn't leaving the ignition switch on accidentally or turning the ignition on without engaging the starter immediately. That can burn the points out if they are in contact.

oilleaker1 · Post by **oilleaker1** » Wed Oct 17, 2018 7:17 am

Already asked. The answer was no, he did not leave the switch on for a abnormal amount of time. Oilly

Post by **wesk** » Wed Oct 17, 2018 9:23 am

Abnormal amount of time is rather arbitrary. If the points were open after shutdown you can leave the switch on overnight and not harm the points. If the points are closed after shutdown it only takes a few minutes to burn the contacts. Now if this guy has short term memory issues and often steps out of the jeep with the engine off and the switch on for this "Arbitrary amount" of time then it just may be the switch. Anytime you want to power these jeeps up to operate something while the engine is off you must disable the #12 wire or you always run the risk of burning points in just a few minutes.

Not all 24 V coils have internal resistance. However most do. You can review page 2 of my photo album index and cruise thru Ignition Systems:

Note Primary resistance value!

These are just a few of the Doc's in my photo album.

Note the coil primary resistance check on the Prestolite Data Sheet. That will tell you if the internal resistance is kaput or not.

oilleaker1 · Post by **oilleaker1** » Wed Oct 17, 2018 12:37 pm

Thanks Wes. The coil test data from prestolite is what we need to check next. As far as testing microfarads

, well that is beyond me. Ohms I recognize.

interesting how just turning on the switch to test the heater blower or lights will fry the points in minutes if they are closed.

Oilly

RICKG · Post by **RICKG** » Wed Oct 17, 2018 1:36 pm

Pic from Wes' foto album.

RICKG · Post by **RICKG** » Wed Oct 17, 2018 1:48 pm

Wes, respectfully request permission to post a few of your ign sys fotos to a discussion ongoing at Scoutpilot's old jeep carb page as well. Not to terminate the discussion here on WillysM but to supplement the other..
RickG.

G740 · Post by **G740** » Wed Oct 17, 2018 7:28 pm

Huge difference in point sets. It is probably not the coil. I have had this conversation with a ton of customers and when they use my point sets, they do not have this issue.
John
MWM, Inc.

Post by **wesk** » Wed Oct 17, 2018 9:39 pm

Rick, No problem.

John, You lost us there.

Huge difference in point sets.

Which points sets?

oilleaker1 · Post by **oilleaker1** » Thu Oct 18, 2018 4:52 am

I had another friend who bought a set of Napa Echlin points and his Jeep would stumble and fall flat on it's face above a certain RPM. I took a look and discovered he did not install the spring steel band under the arm of the points on one side correctly. The only tension was the copper band. He had points bounce.

I've had no problems with the Echlin points in my Jeeps. I'm not a fan of the copper band with blue insulating sleeve condenser that Napa sells.

I'd like to see/hear what type of points John B. is talking about. Oilly

RICKG · Post by **RICKG** » Thu Oct 18, 2018 9:03 am

wesk wrote:Rick, No problem.

John, You lost us there.

Huge difference in point sets.
Which points sets?

Rick, No problem. Thanks Wes.

John, You lost us there. I called John this AM and ordered a set of points- when they arrive i'll inspect, compare and post pics.

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RICKG · Post by **RICKG** » Fri Oct 19, 2018 1:28 pm

A tidbit I learned today..
a condenser with too much capacitance will cause metal transfer to points stationary mounting side.
a condenser with too little capacitance will cause metal transfer to points moving arm side.

in my case the transfer was from stationary mount to moving arm side.

Still researching..

RICKG · Post by **RICKG** » Sun Oct 21, 2018 12:54 pm

Blue streak points and cond sold by Uncle John @ MWM on left, Napa-Echlin on rt.
The visible differences are the felt lube wick on the Blue streak, the stationary contact
on the Blue streak is vented (like a donut) whereas the Napa is not.

oilleaker1 · Post by **oilleaker1** » Sun Oct 21, 2018 2:26 pm

So, less points contact on the stationary side. Gets hotter quicker or slower. Cools faster no doubt. Black plastic VS bakelite cam rider? Wears longer or shorter? Lots to consider.

Then there is Petronix with no points. Electronic trigger instead.

Just fix it and tell me what works so I don't have to think, just take a nap and ride along on your shoulders correct?

Post by **wesk** » Sun Oct 21, 2018 3:15 pm

Rick, Any manufacturer's markings or place of origin markings on any of the four?