COIL BAD?

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
JMZ421
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Re: COIL BAD?

Post by JMZ421 » Sat May 27, 2017 1:01 pm

I have spent the last 2 nights trying to figure out why M38 would start then idle a bit then stall. It has been an ongoing issue. I found a vacuum leak at the air cleaner with spray and fixed that. I sprayed the entire engine and and appears NO vaccum leaks. Distributor has all new parts. I lubed everything in distributor . I tightned all vaccum lines and changed the fuel filter. I cleaned all grounds. I am getting a good squirt of fuel. The timing appeared on but I decided to move the distributor anyway and now it idles OK!! Right when it wanted to stall I turned the distributor clockwise a bit and it held the idle, I tightned. Now the pulley marks are off when I hit it with the light, but it does idle now. Can you please give me your thoughts. Do I need to adjust valves as I was told before? I appreciate your help, John


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Re: COIL BAD?

Post by Joe Gopan » Sat May 27, 2017 5:11 pm

Take out your plugs (I hope you are not tightening the brass nuts more than finger tight) Turn the engine over with your thumb over #1 and stop at top dead center. Where the rotor pointing?
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JMZ421
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Re: COIL BAD?

Post by JMZ421 » Sun May 28, 2017 4:53 am

Yes, I actually checked that first thing and indeed rotor is pointing at lower left at TDC, 1,3,4,2. The engine was rebuilt in 1998 and not used much at all since. My block is MC 47190 . Now, there is a pointer on the timimg cover and notch in pulley. Could this be off for some reason? Before I had the speed screw in all the way to keep from stalling, now with the timing set as is, I am able to back that speed screw almost all the way to get to idle like it's supposed to be. Thanks again and have a nice Memorial Day, John

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Re: COIL BAD?

Post by JMZ421 » Fri Jun 02, 2017 9:22 am

I finally attempted the valve adjustment on my M38 and I did all this without removing a fender or manifold. 6 of the valves were tight so I am surprised my M38 ran at all. I do not think the valves were touched since 1998 when the engine was rebuilt. There are 2 copper like gaskets on the screws that hold the valve cover in place. Are there small round cork gaskets that the copper presses in to? Your help is appreciated. John

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Re: COIL BAD?

Post by Joe Gopan » Fri Jun 02, 2017 10:07 am

Check your SNL and you will discover 2 Ea. 51875 Copper Gaskets.
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
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JMZ421
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Re: COIL BAD?

Post by JMZ421 » Sat Jun 03, 2017 1:40 pm

Ok will do that Thanks, John

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Re: COIL BAD?

Post by JMZ421 » Fri Jun 09, 2017 12:23 pm

UPDATE:

I adjusted the valves and WOW, what a difference and more power. She even idles now. Some of the valves had like no gap whatsoever. I only have to adjust the timing a little and adjust the speed screw and I think Im good. This valve adjustment must have been the problem all along. The jeep even sounds and feels like so much more get up and go. Thanks everyone for your help with the process to adjust the valves. Hopefully bring her to some shows now. John

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Re: COIL BAD?

Post by Wolfman » Sun Jun 11, 2017 6:57 am

Outstanding !!!!
:D go have some fun !! :D
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Re: COIL BAD?

Post by JMZ421 » Sun Jun 11, 2017 12:09 pm

Thanks Wolfman, the inexpensive vacuum guage was the key to fine tuning. I was getting a sputtering when warm and I hooked up that gauge, maximized the reading by turing the distributor then backed off the speed screw until almost a stall and then adjusted the idle mixture screw until the vac guage improved even more. Now, lots of pep and no more sputtering. Thanks again John

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Re: COIL BAD?

Post by diamondjim » Wed Apr 04, 2018 4:14 pm

I bet its the new condenser,drove my M170 on the MVPA rt 66 convoy,went threw 2 shiny coils,3 new condensers ,1 brand new dist cap(century brand/not firing on #3),all aftermarket stuff is junk,jim


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