Posted: Tue Aug 07, 2018 10:37 am Post subject: Is it worth changing a 12v to a 24v
Ok long post with questions. I bought what I thought was m38a1. I didn't do much research or even know how to identify and actual m38a1. I got it home and it was a cj5. The body was so beat up that I scrapped it. I have since then taken the motor and it is in the process of being rebuilt. I have also bought an actual m38a1 tub rolling chassis. I am wanting as close to orginal as possible m38a1. the motor is set up 12v. is it worth the money to change it to a 24v system? Ive been thinking about this for a while but I don't think it will add any value to the jeep because its going to have a cj engine without the fording system and so forth. any advice would be helpful. Thank you
It does add a lot of value to a well done restoration.
If you are building a daily driver and intend to make it as street worthy as possible by today's standard then the 24V system does not add any serious value to your project. But do keep in mind that the tub's electrics and instruments are all 24V so when folks start preaching too much money they usually are not considering the cost of converting the entire jeep to 12 volts.
The military dictated the desire for 24 V electrical systems to all their tactical vehicle OEM's starting in 1948 for several reasons. Much of their heavy equipment was already 24V. 24V meant much better starting in cold climates. And 24V gave them commonality in parts in their supply system and commonality with their NATO allies. The only reason our civilian cars are still 12 volts is mass economics and supplier demand and consumer desires.
You do have the option of maintaining some collector value with your M38A1 by keeping the entire electrical system 24V. And this is not that expensive. Yet you can maintain a modern level of convenience and cost. Many commercial and emergency vehicles in our country 24V. You can buy a 24 V delco one wire alternator rated at 100 amps and that alternator is 1/4th the size of the standard military 24V 25A generator. Or you can buy a used 12V delco one wire 60 or 90 amp alternator and have the auto/electric shop convert it to 24V. There are inexpensive mounting brackets available on the aftermarket for them. Stay with your CJ5 F134's original YF Carb and Civvy distributor. A simple ballast resister on the firewall will accommodate it. You can have the starter rewound for 24V as well. Then leave the tub wiring the way it was. This is how I set up my M38.
Why would I do a nice period correct resto on my M38 and use a Delco one wire 24 volt alternator you ask? Well price, weight and reliability. The military were aware of the limitations their 24V 25A generators had concerning ability to operated heavy loads like the 50's vintage radios so they developed several options. They offered a 60 Amp alternator conversion that was the same size and weight as the 24V 25A generator, They also offered complex 100 amp and 300 amp systems for large radio systems that were truck/jeep mounted. I use a 60 Amp GI alternator on my M37 but be careful, the sticker shock of over $300 will turn you away from that option. Just the replacement regulator for the 60A alternator is over $150. So when you look at my M38 it looks exactly like an Air Force M38 in 1952 until you open the hood and see the tiny Delco 24V 60A alternator and you notive the big military external regulator mounting plate on the right frame is missing.
So my advice is simple, think the whole thing out carefully before you make the final decision on 24V stock, 24V modern, 12V conversion engine only, 12V conversion entire jeep. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Really interesting reading Wes. I to am in kind of the same boat. I was leaning towards a 12v restoration but sometimes think I should go 24v. I am basically starting from scratch as the only 12v components I currently have are the starter and some gauges. The original wiring harness was brittle and kind of hacked up so I yanked it and when I started adding the cost of everything I would need to restore it to original it really started to add up but after reading your post about converting 12v parts to 24v it make me rethink things but I would still need a $800 wiring harness plus also what about wanting my jeep to be street legal I don't think the blackout lights would pass nys inspection. Is there such a thing as 24v taillights and 24v front blinkers?
Yes, the tail lights will pass inspection muster, but it helps to change the covers to "Gamma Goat" lenses. They came on a later M vehicle but are far more visible. Turn signals in front...there is M way to achieve that too. There are stand alone turn signals that can be added, or you can just change the wiring and the covers on the front blackout marker lights to amber. _________________ 2004 M1025, 1952 Dodge M37, 1968 Dodge M615 export ambulance, 1942 MB script, 1948 FrankenJeep CJ2A/M38, 1951 M38, (2) M1941 Sperry 60" Anti-Aircraft Searchlight, (3) John Deere M-gators.
I am basically starting from scratch as the only 12v components I currently have are the starter and some gauges.
This is why I suggested you stop, inventory your project, research costs and make a firm choice on what level of resto you wish to do.
The original wiring harness was brittle and kind of hacked up so I yanked it and when I started adding the cost of everything I would need to restore it to original it really started to add up but after reading your post about converting 12v parts to 24v it make me rethink things but I would still need a $800 wiring harness
Either way you will need a harness. Have you priced a replacement CJ5 harness yet? I refuse to pay that $800 price tag and when I get my CJ5 1960 V-6 project ready I will not pay $400 - $500 for a CJ 5 replacement harness. You have the original M38A1 Harness and so all you need is fresh wire and fresh rubber pieces for the metal Douglas connectors. I have scratch built these harnesses in the past. They are not that tough. Now that I am over 70 I cheat a bit and buy cheap surplus later model military heavy truck harnesses and adapt the new harness with most of the connectors I needed right on it to the jeep. The adapting generally means making length adjustments to parts of the harness which is terribly simple.
I don't think the blackout lights would pass nys inspection.
Most states allow minimal lighting in the case of antique / classic cars & trucks so long as it meets the minimum which is usually one tail/brake lamp. two headlamps and a pair of front parking lamps. Most vintage jeeps meet these requirements stock. Granted you should check your DMV first before making any choices. For the sake of safety with a driver that I was restoring with 24V electrics I would upgrade to military add-on turn signal kit (2 are available) early and late and either fits the 24V military jeeps. Or you can go to an aftermarket 24 volt system (yes they are out there). The original blackout lighting system on the M38's and the M38A1 series meet the minimums in most states in their original stock form. The service drive position gives you one red tail/stop lamp, two white front parking lamps and two headlights with Hi/Lo beams. However again in the interest of safety one should add a second rear red tail/stop lamp which entails very minor altering of the rear light harness.
Is there such a thing as 24v taillights and 24v front blinkers?
Conversion of lamps simply requires switching the existing lamp with one of the desired voltage. Both the military turn signal kits will give you a pair of turn lamps on the front and a pair of turn lamps on the rear. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
I guess the biggest issue for me when deciding whether to go 12v or 24v was my lack of 24v components and the difficulty and expense of finding them. I agree with you Wes I do not want to spend $800 on a harness but the one that I pulled out is incomplete I believe. Looking at the photo of the three harness zones I assume zone c is the engine compartment which is missing from my harness. I bought my jeep without an engine so everything 24v under the hood was gone except the regulator. So as of right now I have very little 24v components except the regulator and gauges and a partial harness and I am also missing bo lights front and rear. The only 12v parts that I have on hand so far are some gauges and starter. So as you can see I could go in either direction but I am really lacking in the 24v department so that is why I was leaning more towards 12v.
Now that I am over 70 I cheat a bit and buy cheap surplus later model military heavy truck harnesses and adapt the new harness with most of the connectors I needed right on it to the jeep. The adapting generally means making length adjustments to parts of the harness which is terribly simple.
I had considered this. I assume you mean the M35 and similar trucks? What are you finding to be a "cheap" price?
Posted: Wed Aug 08, 2018 2:00 pm Post subject: 12v to 24v turn signals.
Wesk, I'm sorry if I missed it but can you tell me when they switched to the late model transistorized turn signal switch. I haven't tried mine but I'm hoping it will work with 12v and a standard 3 pole flasher. It's off of a Vietnam era vehicle. Thanks. _________________ 1952 M-38 # 53623 - 2-52. M 416 trailer.
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