Left ignition switch ON (still won't start)

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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Scott in NM
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Left ignition switch ON (still won't start)

Post by Scott in NM » Mon Mar 05, 2018 5:19 pm

This is a continuation of my previous post, but different problem.

Replaced coil, cranks nicely, still won't start. Points still seem to be OK. So now the questions is - - What makes electrical contact between the distributor cap and the high voltage side of the top of the coil? I don't recall pulling any extra parts out, but find it hard to believe that the distributor cap and the top of the coil are machined so precisely that contact is made when the cap is put on. I would expect some kind of a spring mechanism, similar to that at the rotor, to ensure electrical continuity. Didn't pull anything out, nothing in the ORD 9, but that doesn't mean I'm not missing something.

If no contact between distributor cap and the high voltage terminal, it won't start, and I can't think of any other problem relating to the initial problem that prevents the engine from starting. Anyone care to hazard a guess how best to proceed from here?

Scott

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Re: Left ignition switch ON (still won't start)

Post by g.keating » Mon Mar 05, 2018 10:36 pm

are you missing the spring on the inner cap????



https://www.ebay.ca/itm/M151-M38-Distri ... L-&vxp=mtr

Scott in NM
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Re: Left ignition switch ON (still won't start)

Post by Scott in NM » Tue Mar 06, 2018 8:33 am

Don't know what I'm missing if anything, I have no reference.

There is a spring that makes contact with the rotor. I don't know if there is anything that is supposed to sit on top of the high voltage side of the coil.

Scott

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Re: Left ignition switch ON (still won't start)

Post by muttguru » Tue Mar 06, 2018 10:09 am

Scott...

look inside your distributor cap. You should see a carbon tip in the centre of the inner cap. This touches the rotor arm.
There is a projection from the side of the inner cap....at the tip of the projection there is a small spring attached. This spring touches the hi-voltage core of the coil.

If the spring is missing or damaged, or if the carbon tip in the inner cap is missing or chipped, replace the inner cap.

Have you made certain that the new coil you have fitted is serviceable? If it's a shiny chrome coil.....try a KNOWN working one instead.
Ken
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Re: Left ignition switch ON (still won't start)

Post by g.keating » Tue Mar 06, 2018 1:21 pm

look at the eBay link i posted in my post above for a picture reference


Scott in NM
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Re: Left ignition switch ON (still won't start)

Post by Scott in NM » Thu Mar 08, 2018 4:26 pm

OK, let's start over on this one. (But still doesn't start).

After resolving a few issues, not the least that I'm stupid, I've put everything back together. Disconnected #1 spark plug lead and had wife start jeep. Got a small yellow, periodic, rather anemic spark (no snap or noise) when the lead got about 1/8" from the engine block. I don't do this procedure often (last time was when I was working on Pharoah's chariot), but kind of remember it should be a violent blue spark when held about 1/2" from the block with a clearly audible snap. So if my memory is correct, the coil is not putting out enough juice. Any of you more experienced care to weigh in whether I'm correct, and if so, is there another coil test I can perform, or do I just repair by substitution?

Scott

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Re: Left ignition switch ON (still won't start)

Post by Ben Dover » Thu Mar 08, 2018 4:38 pm

Check the routing of the two primary wires over the edge of the coil, they can have cracked insulation or get pinched against the inside of the cap and the upper edge of the coil which can affect the spark. The pigtails are easy to make, or you can check with your favorite parts supplier..
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Scott in NM
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Re: Left ignition switch ON (still won't start)

Post by Scott in NM » Fri Mar 09, 2018 10:28 am

Was careful about the pinching and didn't see any cracked insulation. Assume I need another coil?

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Re: Left ignition switch ON (still won't start)

Post by g.keating » Fri Mar 09, 2018 11:42 am

this was discussed several times on the willysmjeeps forum.(Linked below). If you belong than do a search for testing coil. if you don't belong it is worth it for another source of great info. start your topic there




http://www.willysmjeeps.com/v2/

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Re: Left ignition switch ON (still won't start)

Post by Ben Dover » Fri Mar 09, 2018 12:40 pm

Fold up a fresh dollar bill and insert it between the points to wipe clean any residue of sorts. :wink:
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Re: Left ignition switch ON (still won't start)

Post by W. Winget » Fri Mar 09, 2018 7:27 pm

Is there a condenser grounding out or weak?
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Re: Left ignition switch ON (still won't start)

Post by Ben Dover » Sat Mar 10, 2018 6:30 am

The Colonel asked a good question, that Capacitor where #12 wire enters the distributor can act up and cause fireing fits, it's worth a look. I keep spares but did not think to mention the capacitor.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

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Re: Left ignition switch ON (still won't start)

Post by Radtech » Tue Mar 13, 2018 4:53 pm

Check the resistance between the primary terminals on the coil.All of mine show between 11 and 12.5 OHMS.If the resistance is good the coil is good.You will not get any spark unless you ground the spark plug to the block.I have tested all 4 coils in my M38 and they all work fine.

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