24 Volt?

1955 CJ5. How can I visually identify a 24 volt system?:? Is the starter different? There has been an alternator installed, in place of the generator. I am looking to try to start it up and don't want to burn everything out if it is converted to a 12 volt system. Also if it is a 24V, will it start with 12 volts? Thanks

 

Post pictures.

The 24V parts were only used in the M38A1 military version, and they are expensive to buy or repair, bulky and waterproof. No civilian version, ie CJ-5, came with a 24V system. The M38A1 used 2 12V batteries in series, in a waterproof battery box in the cowl. Hard to mistake one for the other.

 

I have the M38A1 version. The battery box is in the cowl and ignition system is all water proof. I am questioning because the generator has been replaced by an alternator. If I just hook up a 12v battery, would it even turn over or start if it is indeed a 24v system? I will take some pictures today and post.

 

Check the battery cables. If it was still 24 volt it will be set up for two batteries in series, in the cowl. There is a jumper between the two batteries.

You could also try putting 12 volts into the system and see if the lights are bright. If not, it needs 24volts. I very much doubt it would operate at all on 12v.

If the headlights have three pigtail wires with waterproof connecters on them, they are still 24 volt. http://www.us-army-military-shop.de/images/product_images/popup_images/6246_0.jpg

Personally I love the the military waterproof components - very high quality. Durable and maintenance free in my experience.

 

Thanks for the info. I will take a look at the headlight wiring. As far as the batteries, there are none, just a pos and neg cable.
Here is a picture of the set up. The alternator is pretty large.
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Do the pos and neg cables look like they could reach to fit onto a single battery?

Maybe you can find a number on the Alternator and google it. (Catapilar and other heavy trucks/vehicles sometimes have 24volt systems. Aircraft too.)

BTW many military surplus jeeps are low hours, sold by the govt. at about 25K miles to fire departments etc.

 

The healights are different wiring than what's pictured in the link. I pulled a headlight bulb and it was marked 28V. I then pulled a signal light and googled the part number (GE 1665) and it turns out to be 28 Volt. So now I'm going to install two batteries within the next couple of days and see if she will fire up and run!
The odemeter reads a little over 33k miles. Wish me luck.

 

Good luck!

Try and get the G.I. manual (TM9-8014) and parts book (ORD 9 SNL G-758 )

They are also accessible free on-line.

 

Steelsoldiers.com is awesome for all the military stuff

 

24v alternators are easy to find and it's probable that an inspection of the back side of the alternator will show it stamped 24v. It looks from the pic that the original dist and starter are intact along with the original carb, so the A1 seems pretty stock, except for the alternator.

The system you have will be lighter and essentially trouble free as far as charging is concerned. The use of an internally-resisted alternator gets rid of both the bulky generator (which weighs a ton) and the cantankerous regulator. Also, notice that the original set up has two fan belts. I think this is due to the sheer amount of engine power needed to turn the generator, so if that is the case, you should benefit- even if only slightly- in the power category. I can't dispute PeteL when he says the parts are high quality and traditionally have low miles, but they are ~60 yrs old. Quite a few A1 owners have trouble with the charging system, especially the regulator.

One thing nice about keeping the 24v system is you can retain the original gauges; as I recall, they are all voltage-specific.

My A1 came with a 12v conversion by the PO- everything else was bone stock. I put on a 4008 distributor. It came to me with about 31000 on the odometer and I can trace its history back to the Oregon Natl Guard unit it was in, so I think that's accurate.

 

I think the M38A1 may have carried either a generator OR an optional alternator in military service. The parts book shows both.

The dual fan belt may be partly because at 25 amps and 24 volts, it had about twice the output of a civilian generator, hence twice the drag at full load.
Also because, military.

Troubles "with the charging system" and regulation may come from trying to keep two individual batteries in series equally charged. If the internal resistances become unbalanced, one will never get a full charge and the other will continuously overcharge. They must be a matched pair, and always "topped off" equally.

NOS parts prices may be higher than chinese stuff at Pep Boys, but they are very available, since the specs never changed year to year, many are common with other M-series vehicles, and the govt kept warehouses full of spares.

 

Thanks everyone for the info. I am already having fun learning about these.

 

My Sept 1956 ORD 9 SNL G-758 shows both Autolite and Delco Remy generators but no alternators. A1s were built for the USMC into the 60s and may have been the A1s that were upgraded to alternators that show in your book.

If you want to use your A1 as a daily driver, most people would benefit from going to the alternator. It's no different than any other upgrade. From what I read in the past, the Army mechanics used to cuss the 24 volt systems even when the jeeps were new.

I buy NOS almost exclusively unless I simply can't find it...or, if NOS means it has exceeded its shelf life. Rubber components (such as carb parts) come into this category. And occasionally, new parts can sometimes simply reflect better material used. I wonder what a NOS 24v regulator would run?

 

I don't disagree. But I love that everything is sealed, always factory fresh internally. I've had no issues.

 

Oh, I hear you on that. The M series jeeps had a great variety of idiosynchrases that are fascinating (IMO).

 

Think I would disconnect the cables from the starter, put the nuts back on to protect the threads and use jumper cables from a 12 volt battery to see if it would turn over. Using a 12 volt battery on 24 volt system is better than on a 6 volt but I would wont to start out slow and isolate other circuits.