NO SPARK

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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YLG80
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Re: NO SPARK

Post by YLG80 » Thu May 30, 2024 5:21 am

Hi John,
If you have a multimeter, it’s time to use it in ohmmeter mode.
Disconnect the battery first, as you cannot use the multimeter in that mode when the circuit is live.
You would destroy the meter, or at the minimum burn the fuse inside.

In ohmmeter (continuity test), you should insure that the ground connexions are OK in your distributor et likely at the filter between the ignition switch and the distributor.
I read that you have changed the coil, so we could assume that it is OK, but perhaps the coil is not correctly grounded inside the distributor,
Is there a spark when you manually open and close the points?
Is the insulator in good shape at the connexion to the point plate. see here
http://willysmjeeps.com/v2/modules.php? ... 4286#64286

Again you could test it with the multimeter in ohmmeter mode.
IMG_8037.jpeg

Check also if the points are perfectly clean. When closed, the ohmmeter should display nearly 0 ohms.


Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794


JMZ421
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Re: NO SPARK

Post by JMZ421 » Fri May 31, 2024 2:51 am

Yves, Thank for helping, I have been busy at work. I am going to look at the connections in the distributor. Really nothing there.
What is this "thermal" connection where the condenser and coil wire connect? I thought the coil was grounded once you install the 2 screws in the housing. I do get an sporadic light spark and occasional nice snap opening the points so I am wondering if these 7 year old batteries just are shot even though they were tested good. I need batteries anyway after 7 years of being on trickle charge. They are Napa 51R . I was getting between 22 and 24 volts when starting on meter.

Does anyone know where this " Small Insulator" is in the distributor? It's in or near the where the wires and points are tightened together. An old post mentioned this could cause connections issues. Thank you

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Re: NO SPARK

Post by Ron D » Fri May 31, 2024 1:36 pm

JMZ421 wrote:
Fri May 31, 2024 2:51 am
Does anyone know where this " Small Insulator" is in the distributor? It's in or near the where the wires and points are tightened together. An old post mentioned this could cause connections issues.
Did you look at the photo in the link provided above by Yves, and here again: http://willysmjeeps.com/v2/modules.php? ... 4286#64286

It's labeled "Insulated Terminal Bracket" in the photo.
Can't miss it. But you have to look.
Ron D
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Re: NO SPARK

Post by JMZ421 » Fri May 31, 2024 6:09 pm

Hi Ron. Yes I have seen that photo 25 times and all I can gather is the coil wire and condenser wire connectors are insulated. I was thinking there was some sort of special washer/spacer/fiber or something in that connection where the wires and points are connected That is why I asked. The arrow is pointed to a screw. I just wanted to make sure I wasn’t missing something but after a couple phone calls today I am not. Thanks. John



is another photo of that

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Re: NO SPARK

Post by YLG80 » Sat Jun 01, 2024 12:39 am

JMZ421 wrote:
Fri May 31, 2024 6:09 pm
Hi Ron. Yes I have seen that photo 25 times and all I can gather is the coil wire and condenser wire connectors are insulated. I was thinking there was some sort of special washer/spacer/fiber or something in that connection where the wires and points are connected That is why I asked. The arrow is pointed to a screw. I just wanted to make sure I wasn’t missing something but after a couple phone calls today I am not. Thanks. John



is another photo of that
HI john,
Normally you have two insulated plates with a hole and an insulated sleeve.
The insulated plates are assembled on both sides of the ignition points connector and the sleeve insulates the screw from the ground.
If that insulating assembly is broken, there is no way to get good sparks.
Yves.
Ford GPW 1943 - Louisville - DoD 12-7-43
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Re: NO SPARK

Post by YLG80 » Sat Jun 01, 2024 2:39 am

JMZ421 wrote:
Fri May 31, 2024 6:09 pm
Hi Ron. Yes I have seen that photo 25 times and all I can gather is the coil wire and condenser wire connectors are insulated. I was thinking there was some sort of special washer/spacer/fiber or something in that connection where the wires and points are connected That is why I asked. The arrow is pointed to a screw. I just wanted to make sure I wasn’t missing something but after a couple phone calls today I am not. Thanks. John



is another photo of that
Perhaps in an M38 24V, this is that configuration.
http://www.willysmjeeps.com/v2/modules. ... ic&p=78588
They give the method to probe/test the distributor and the coil.

In an M201 shielded distributor similar to the one in the M38, the insulator is there :

M201_DISTRIBUTOR_PLATE_INSULATOR.jpg

Yves
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Re: NO SPARK

Post by JMZ421 » Sat Jun 01, 2024 8:34 am

Yves, all I have in the distributor is a threaded bolt going thru that connector piece with the 2 rivets with 2 nuts on each side and that's the way it has been since I have owned this for maybe 8 years now. If the setup was correct from the beginning I would have made sure to keep it that way. After I cut this tree down in my yard I am going to finish tightening up the grounds on the Jeep and focus on this now. I need the find the correct parts for this. I want to Thank you and the others for helping, Maybe I can find a good distributor rebuilder that can me.

The link you sent me is very interesting. Thank you, John

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Re: NO SPARK

Post by YLG80 » Sat Jun 01, 2024 10:16 am

« Timbeeeer! »

So the point little plate is most probably sitting on an insulator.
Yves
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Re: NO SPARK

Post by JMZ421 » Sun Jun 02, 2024 3:10 pm

Update:

Yesterday I went to auto parts store and they charged my batteries, even though they told me the batteries checked out Ok prior. Actually another chain did also. This morning after coming home from church I installed a new reproduction Ammeter. The original AC was in there but it never worked since I had it. I go to try and start and it fires up after the 3rd attempt. It was really flooded from prior attempts. I let her idle for about 45 minutes pressing on the pedal every so often and she kept running although I am getting a little putt, putt, sound out of the exhaust. I did drive around the block and came right back but I started it several times since and she fires up. I purchased the ammeter so I could follow the manual. I was getting power to the #12 plug at the distributor before the ammeter was changed. IDK, maybe these freaking batteries are the issue. I wasn't sure if the ammeter has anything to do with this if had power to distributor.

Does anyone know what the red stuff is around the terminal connection like a paint!! Is that called "Insulating Varnish" That picture Yves shows that painted around that terminal connection. I finally understand there is a small pad of some sort installed underneath(as Yves showed me) that terminal connection for grounding.

Hope everyone enjoys my stories, Thanks, John

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Re: NO SPARK

Post by YLG80 » Mon Jun 03, 2024 11:49 pm

Hi John,
I believe that the red insulation is simply red RTV silicone.

Always test your battery under heavy load, like while cranking the engine.

I also have an original AC ammeter that does not produce any reading.
As long as the coil inside the gauge is not broken, it does not cause any problem with the jeep.
I still have to open mine and debug the issue.
Probably a demagnetized frame.
A few weeks ago I have prepared a resistive load to debug that gauge.
I still need to add a few 12V 50W halogen lamps to load further the ammeter and get readings in the 30-40 A range.



I will share what I discover :wink:

Yves
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Re: NO SPARK

Post by JMZ421 » Wed Jun 05, 2024 1:40 am

Good info Yves, Thanks. I did purchase a small bottle of red "insulating varnish" pretty cheap from Amazon. It arrived yesterday and has two small brushes. Again, while I was cleaning the distributor plate I did see some red area around that insulator and it came off. I then saw that picture and I will take a second an recoat that terminal area with this stuff so there is no arching or grounding. John

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Re: NO SPARK

Post by HoustonMule » Wed Jun 05, 2024 12:33 pm

I have to agree with possible loss of amperage though you measured 24 vdc. Same issue on my buddies M38. Just rebuilt engine and could not get it to fire up. Weak to no spark. Changed all distributor parts and no change. Ran a jumper wire directly from batteries to distributor feed wire input and we had hot spark. Replaced military ignition switch and all good.


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