willysmjeeps.com

Hello!

I'm having some troubles with my M38A1 engine. More specificly the ignition system.
Does anyone know what order the sparkplug cables should be in from the distributor to the sylinders? And wich sylinder is nr. 1, 2, 3 and 4? A drawing over this would be fantastic.

Regards hannijr

Fig 79 in TM 8014 was revised in like 1960. The numbers should be changed to 1 is 3, 4 is 2, 2 is 1, 3 is 4. I just installed my distributor after overhaul of my engine and scratched my head until i found the change in the downloads section here. So that makes the firing order 1342. one is the front by the fan then 234 to the rear. figure 79 almost screwed me up but I knew the distributor was installed correctly and the rotor was pointing to the wrong wire until I found the revision in the updates download section then it was AHA.

Ok I may be having the same issue with my M38A1. I am not sure which version of TM 8014 I am going by but I changed my distributor cap and now the engine won't start. It turns over but just makes an occasional puff of smoke out the rear tailpipe and seems to me to be a firing order issue. Going by 1 is by the fan and 2,3,4 preceding to the cab I put the wires on the distributor cap as follows (IP is the inspection plug).


------4---3
IP
------2---1

What rdsar2k is saying is that it actually should be:


------2---4
IP
------1---3

Is this correct?

So to be clear:

D = 1
C = 2
A = 3
B = 4

Yep! Just like my photos.

A word of caution if you do not understand the ignition system's functioning very clearly. Re-arranging wires will not solve any problems with an improperly installed distributor. Not only does #1 wire need to be at the 7 O'clock position but the rotor needs to be in the same 7 O'clock position with #1 cylinder TDC on compression.

Thanks Wes...I almost want to run out to the garage and try swapping them now...darn job gets in the way too many times!

Well got it up and running! Woohoo! Wes - I knew it was installed right, just kept scratching my head taking the manual as gospel. Thanks for all the help!

I feel like a lump of coal

Sorry! Thanks rdsar2k! You were the one that originally mentioned it and identified the problem and I neglected that. I feel like the coal now..

I was actually surprised this issue wasn't discussed more at some point in time. To be honest that is why I posted a picture as well just to make sure it was clear to everyone.

This is why I love my jeep and love working on it. Reminds me of a simpler time when everyone helped everyone else out. Today if this would have happened someone would have sued the manufacturer, the mechanic, the supplier, etc etc etc!

Wes is a guru. No doubt. I was just acting the neglected child. The original cap/wire location will work but you have to severely rotate the distributor. I considered that before I found the update to the manual. The problem for me is it didn't "look" right based on all the pictures in all the manuals. The distributor being rotated horizontal seemed to stretch all the vacuum lines and it was at the end of the rotation adjustment for the distributor. After stowing this in the back of my brain I have begun to notice that half of guy's rigs have the distributor one way and half another. You got screwed up in that someone timed yours based on the revised way and you tried to wire the cap the old pictured way.

I have to revel the small victories as I will never be able to compete with the guru's. I do enjoy the nuances of these Jeeps.

I am wanting to know the correct way to install spark plug wires on my 1955 M38A1. For some reason I can't view the pictures that someone posted on here. Please help. Thanks

#? #?
IP
#? #?

2---4
IP
------1---3


Is this correct? Thanks

If you installed the distributor correctly per the TM then this is the correct placement of wires.




This is the correct position of the distributor and rotor with #1 piston TDC on compression.

Thanks, Does anyone have any pictures showing the spark plug wires labeled correctly on the distributer for a M38A1 24 volt system? I'm still not sure that I have mine corrrect. My Jeep will start but "misses" like crazy. Thanks

If you download the Change 5 from our free downloads page and read it then apply the pen and ink change to your copy of TM 9-8014 you will have them correct.
http://willysmjeeps.com/downloads/TM%20 ... 7MAR60.pdf

It is best you do this now in your manual because as is usually the case we come back two years later having completely forgot about this dog and pony show and wow our manual shows the wires not the way I have them so we change the wires and it won't start and we pop up on the Mjeeps site and ask the beginning question.

Or just look up the firing order on page 170 of TM 9-8014 and apply it to the illustration I posted starting with #1 on the rotor in the photo and then go around CCW with the remaining 3 wires following the firing order.