Compatible distributor?

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
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Scott in NM
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Compatible distributor?

Post by Scott in NM » Tue Jul 20, 2021 8:00 am

My M38 still doesn't work after the engine rebuild and at least three months of trying. A team of five old-fart mechanics are baffled as am I as the distributor carburetor, and fuel pump have all been professionally rebuilt and individually tested per appropriate manuals and meet all specs. Unfortunately, it still has no power and is hard to start. Will now start repair by replacement starting with the distributor. Is there a replacement distributor that is compatible with an L134 engine and 24V system? The local auto parts stores never answer phones so I can't ask and hope the community knowledge can assist.

Scott


sweetjeep
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Re: Compatible distributor?

Post by sweetjeep » Wed Jul 21, 2021 6:52 pm

Serious question: Do you have the right wires to the right plugs? I know this sounds elementary, and "Jesus Morgan, YES!", but once upon a time I swore up and down I did too, and in fact I had them reversed (if I recall correctly) and it was running forward, but on 2 cylinders, and I suspect purely on accident. But, it started (hard) and then ran with NO power.

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W. Winget
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Re: Compatible distributor?

Post by W. Winget » Thu Jul 22, 2021 5:03 am

You could go backwards and install a distributor from a MB/GPW/CJ2/CJ3 with standard wires. As long as you use one from a gear driven camshaft (which M38 would be).

I cannot state emphatically the base of the dizzy/and it's drive shaft will match the drive slot on the M38, but it should.
This means you would go backwards to 12 volts, and regular sparkplugs and wires as well.

Your not going to find anything other than fluids and perhaps hose clamps at a local autoparts store for an M38. :lol:
Ron or other vendor sources on-line would be your best resource.

"A team of five old-fart mechanics are baffled as am I" If they have never worked on 24V military systems they are not the correct mechanics you require perhaps... :wink:

Go back to the basics

Air
Fuel
Compression
Spark

Have to have these for her to run, and in the correct order.
Have you pulled a plug (attached to a sparkplug wire) and placed it on a ground (or ground it with a alligator clip) and cranked the engine to see if it sparks?
24V coils are notorious for being DOA from China, they are just crap. Look at rotor rotation in the dizzy and see if it follows the firing order (embossed on the head) as it rotates to the next wire....as he said, you could be 180 out on wires if it's rotating the opposite way of the firing order :oops:
V/R W. Winget
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dpcd67
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Re: Compatible distributor?

Post by dpcd67 » Thu Jul 22, 2021 7:06 am

Do what WW said.
Fire your "mechanics" they are useless.
Stop replacing parts; (although a Cj2A distributor will fit, your wires won't connect to the cap).
These things are the simplest engines to make run of all and there has to be something obvious in order for them not to run. Get a TM and check what was said above. It will be a "duh" moment when you find the cause.
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Scott in NM
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Re: Compatible distributor?

Post by Scott in NM » Fri Jul 23, 2021 5:25 am

I could go through all the inputs and respond individually but that could take a book. Bottom line, this is what happened:

Since all components were professionally rebuilt and individually tested, that should be eliminated. (I know, if you don't do it yourself how do you know it was done correctly but I won't invest in a complete engine rebuild machine shop, the year or two to learn how to do it, and then let it sit for another 30 years until the next rebuild is required.)

TM's all consulted at every step of the way. I have a complete library both print and digital.

So what happened? Performing yet another spark test with #2 plug wire removed and watching the spark results. Engine gets cranked, mechanic gets a rather nasty jolt that passes through him to another mechanic a foot and a half away. OK, COIL IS GOOD! Although this test had been performed several times previously, he was holding it differently. The small crack in the corner of the pink rubber boot was opened and exposed the high tension wire that was now sticking out. Contact made! Once installed inside the spark plug, spark would be shorted to the spark plug case and not to the gap. I guess engines don't like to run well on three cylinders. Spark plug cables replaced, all spark plugs inspected and resistance testing performed, #2 plug also replaced due to higher than normal resistance. SUCCESS!

Moral of story - The little things become the biggest things very quickly.

Incidentally, anyone know where I can get replacement pink rubber insulator boots that fit inside the spark plug? Hate to scrap an otherwise good wire for the sake of a boot.

Scott

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Re: Compatible distributor?

Post by dpcd67 » Fri Jul 23, 2021 6:58 am

Glad it's running.
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sweetjeep
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Re: Compatible distributor?

Post by sweetjeep » Sun Jul 25, 2021 5:14 pm

Huzzah!

Scott in NM
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Re: Compatible distributor?

Post by Scott in NM » Mon Jul 26, 2021 3:43 am

Not so fast, see the new post "Distributor electrical testing". I think my new condenser burned out the coil somehow. Now I'm afraid to test any new condensers as coils are becoming expensive!

Scott


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