Posted: Fri Sep 21, 2012 9:58 am Post subject: Help with planning electrical system
My 38 came as basically as rolling chassis and some milk crates filled with parts. The electrical system is gone short of a few old parts. The motor was changed at some point to a WW II MB motor, Ford GPW head, etc. I am not going the restoration route since there are so few M38 original parts left. I'm going more towards a jeep that looks like an M38 but I need to economize where I can. I did buy a new reproduction M38 body.
Based on the few electrical parts (headlights, voltage regulator) I have it seems that the electrical system was converted to a civilian six volt with an MB style light switch and key start from a CJ3A.
So I am now laying out my electrical plan. Military 24 volt is out of the question based on the expense. Particularly considering that so much of the original jeep is missing (entire body, electrical system, vacuum system, etc.). I just don't think a full restoration makes any sense when so few original parts are left.
My two options are:
A modern 12 volt with a modern starter, alternator, key start, wiper motors, etc. This would be more reliable and less expensive, however the look of modern parts on a 50's vehicle is not very appealing to me.
The other option is going back to a more visually period correct 6 volt or 12 volt system. Basically using a CJ3A wiring harness and parts. The picture below are the starter and generator that were in one of the milk crates. Is there any way to tell if these are six volt or 12 volt. Do any of the experts here recognize what vehicle they are from originally?
My thought was to have these rebuilt since they look period correct. If they are six volt can they be converted to 12 volt?
As always, your thoughts and suggestions are much appreciated.
1-24 volt electrics aren't much more expensive than 6 or 12 volt rebuilt electrics.
2-Going backwards to 6 volt is not good sense. The reason we developed 12 and 24 volt systems was to improve performance. A properly maintained 12 or 24 volt system will perforn 100% better than a properly maintained 6 volt system.
3-Based on what I percieve to be your position the modern 12 volt system is the answer. The only things that you will notice when showing the jeep are the electric wipers, civvy gauges, civvvy horn, modern one wire alternator and modern wiring harness. You can fool the average smuck by painting the new alternator OD.
4-An accurate ID is not possible from the two photo'd units. One would need tag numbers or in some cases one can come close to model with individual part numbers for things like the end caps and main housings. Those numbers are usually stamped or cast into the parts. The simplest thing you can do is take them to an auto-electric shop and have them bench checked and he should be able to ID them. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Mar 04, 2010 Posts: 37 Location: Kalispell, Montana
Posted: Fri Dec 07, 2012 7:16 pm Post subject:
I have started from a very similar place although it sounds like I had a bit more to begin with. I also have a limited jeep fund and need to save where possible while eventually getting the jeep on the road at some point. I have already committed to a civilian block, but the two subsytems I was wavering on were electric and fuel. You are describing the exact issue I have been thinking about with the electrical system. It occured to me that it is easier to go back and "bolt on" the correct M38 fuel parts years down the road (air cleaner, YS637 carb, fuel pump, etc) whereas the electric system is more of a committed issue (wiring harness, bellhousing/ring gear combo, etc...). For me, it makes sense to locate the 24V parts spending a bit more even if it means running a DJ air cleaner (don"t laugh) on top of a carter WO carb for a while.
Besides, the value you add with the 24V parts will more than pay for themselves if you ever decide to sell. What are the first three questions asked when an M38 comes up for sale on this board and others; original engine? how are the floors/body? still have the 24V system? _________________ 1951 M38 (MC25486)
Joined: Aug 31, 2010 Posts: 1741 Location: SO IDAHO
Posted: Sat Dec 08, 2012 10:44 am Post subject:
You oughta talk to Bretto. He fab'd up a a 12v system and harness recently and to my knowledge is happy with it. I think he built a wiring
diagram as well. _________________ keep 'em rollin'
RICKG MC 51986 DOD 01-52, '50 CJ3a
Joined: Nov 24, 2010 Posts: 1390 Location: Orem, UT
Posted: Sat Dec 08, 2012 10:56 am Post subject:
As Rick says, ya I have a 12V schematic that I threw together that is working fine for me and has a signal circuit incorporated in it. I could send you a copy that you could pick apart or see if it could help you out.
For the wiring, I mainly used 14awg marine wire that is a fine strand fully tinned wire. Then larger gauge wire where applicable.
Brett _________________ Brett
'51 M38
PHOTO DIARY OF MY BUILD
An update. I was able to have the starter and generator shown in the first post rebuilt from 6 volt to 12 volt specs. I purchased a CJ3A wiring harness from Walcks that includes the wiring for a key start and turn signals. I'll be replacing the front blackout lights with amber lenses and using two left tail lights for the rear. I'll also be using 12 volt gauges.
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