12 volt jeeps

[44MB]

Hi everyone

can someone please tell me when were the jeeps converted to 12 volts in wwii. Were they for radio jeeps and when this convcersion was does wqas the battery mounted between the front seats and covere3d in a metal battery box?

i am trying to find out more info about this and correct serial numbers of parts used in this conversion.Any help much appreciated

Many thanks
Andy

[44MB]

Hi
Does anyone know if there was a manual produced showing correct WWII conversion of 6v to 12 volt jeeps? or where i would find details on this.

Many thanks
andy

[Lester Senn]

Andy,you can find the manual for 6 to 12 volt conversion right here on the G.On the homepage click on Jeepdraw link.It is listed towards the bottom of the page along with some other manuals.Look for MWO ORD G503 W7 on the list.Hope this helps.

[44MB]

thanks Lester, I really appreciate your response and help
andy

[44MB]

Hi all

I have a follow up question to this and hope maybe someone can help me with it.

I noticed that 6 -12Volt conversion manual MWO ORD G503 W7 is dated 1948 but does anyone know if these mods were actually done during WWII to same spec as described in this manual ... my jeep is converted to 12 Volt exactly as described in MWO ORD G503 W7 with battery placed between the two front seats etc but I would like to know if this could have been a WWII era conversion or is it strictly post war conversion with early post war parts etc?

Thanks for your help

Andy

[Mark Tombleson]

The W7 modification is in the February 15, 1945 SNL parts book.

There is an article in Army Motors issue 82 that shows the Army doing a comparison test of 4 different 12v generator systems at Fort Hood in a March 10, 1943 report. These were a 26 amp unit fitted in the standard battery spot (with single 12v battery), a 40 amp unit with a 6v battery in the standard spot and 6v cowl mounted similar to what the M38 has, a 55 amp generator mounted in between the seats with a PTO (this was acceped and is the W5 MWO) and the Ford 12v 55 amp conversion with the generator mounted in the standard location, a two battery rack between the seats and most electrical items on the jeep changed to 12v.

I know the 12v PTO units were in production and Navy contract radio jeeps delivered by Willys-Overland in May of 1943.

The following TM for radio installations implies the conversion was in use at least by Januaray 1944.

TECHNICAL MANUAL TM 11-2715
WAR DEPARTMENT WASHINGTON 25, D.C., 26 January 1944
United States Government Printing Office Washington: 1944
Installation of Radio Equipment in Truck, 1/4-Ton, 4 x 4

"Quote"
7) Assembly and Installation
a) Preliminary Check.
(1) For the installation of Radio Set SCR-193-K, it is necessary that Truck, 1/4-ton, 4 x 4, be modified to have a 12-volt electrical system with two 6-volt batteries connected in series and installed between the front seats of the vehicle. These two batteries furnish power for the vehicular electrical system and the radio set. Make sure that the modification of the vehicle's electrical system has been made before starting the installation of the radio set.

(2) For the installation of Radio Set SCR-193-KB in Truck, 1/4-ton, 4 x 4, a power take-off must be installed in the vehicle. A 12-volt generator and regulator is mounted between the front seats of the vehicle and driven by a belt and pulley from the transmission shaft. Two 6-volt batteries are installed, one behind each front seat. The power supplied to the radio set is independent of the vehicular electrical system. Before proceeding with the installation of the radio set, make sure that the power take-off has been installed in the vehicle.

[Fred Coldwell]

Hi all: . . . I noticed that 6 -12Volt conversion manual MWO ORD G503 W7 is dated 1948 but does anyone know if these mods were actually done during WWII to same spec as described in this manual ... my jeep is converted to 12 Volt exactly as described in MWO ORD G503 W7 with battery placed between the two front seats etc but I would like to know if this could have been a WWII era conversion or is it strictly post war conversion with early post war parts etc? Thanks for your help, Andy

Hi Andy:

The first edition of MWO ORD G503-W7 is dated 25 May, 1944, so this 12 volt "Ford" style batteries-between-the-seats conversion kit was issued and installed during WW II. Change 1 to the first edition MWO was issued on 20 March 1945. This information comes from the asterisked (*) footnote on page 1 of MWO ORD G503-W7 dated 27 April 1948. So, yes, this was a WW II era conversion and NOT strictly postwar. You are fortunate to have this 12 volt conversion kit in your jeep. Enjoy it!

[44MB]

Thanks Mark and Fred so much for this fantastic information - this is really helpful.

I guess my next question is - and excuse my ignorance - but how rare is this original equipment - in terms of collectability and insurance purposes etc does it add much value to my jeep over the standard jeep?

Thanks again
Andy

[Mark Tombleson]

Here is a photo I took of a W7 kit for sale at the 2008 Portland Convention.



I don't remember the price or if it was complete but Fred might as he was there also.

I have enough photos of these setups I have gathered and I know there are quite a few I have seen over the last 10 years. I seem to remember the Greek Army surplused a bunch of them.

I'm not really sure it would add much value in general but to the right buyer, perhaps.

[44MB]

Many thanks again Mark for your info and pic - really appreciated.

All best
Andy

[Fred Coldwell]

Here is a photo I took of a W7 kit for sale at the 2008 Portland Convention. . . .I don't remember the price or if it was complete but Fred might as he was there also.
. . . I'm not really sure it would add much value in general but to the right buyer, perhaps.

Hi Andy:

I didn't pay any attention to the W7 kit while I was at the Portland Convention in 2008, but I had a friend who was interested in it and we chatted about it after the convention. I'm not sure this is the same kit he had his eye on, so what follows is hearsay, not necessarily fact. My understanding is a seller in Portland was asking $2,500 for half of a W7 a kit in one of two kit crates. Mark's photo shows mostly the radio suppression engine and between-the-seats battery installation parts. I think, but am not sure, that the full W7 kit had another crate that contained the 12 volt generator, 12 volt voltage regulator, new wiring, etc. that this seller did not have. So I think anyone buying what he offered for sale was buying only half a W7 kit. It did not sell at the convention, as those interested thought his price was too high for just half a kit. Now I'm not positive the photo shows an incomplete kit or that the complete kit came in two crates. On close inspection, the battery tray cover and battery installation parts might be in the pictured crate. But I don't see any 12 volt generator, voltage regulator, etc., so I think its was half of a W7 kit that was too expensive to most people for what was there.

Does an installed W7 kit add value to a jeep? I think that depends on the owner and how he uses his jeep. If he just needs a runabout to haul 3 buddies to the local cafe, the kit adds little to no value because it takes up some usable foot space. OTOH, 12 volts allows the installation of a large radio set in the back of a jeep (to the exclusion of some other uses), so if an owner has few friends and likes large radio sets he can install one and be in heaven. A 12 volt jeep might start better in cold weather with less maintenance than a 6 volt jeep, but two 6 volt batteries in series cost more than one 6 volt battery (or one could use one out-of-sight 12 volt battery in the battery compartment). If a jeep owner likes unusual accessories, the 12 volt kit is that. Some owners prefer a bone stock 6 volt jeep. Bottom line: if an owner had a particular use for 12 volts in a jeep or likes unusual accessories, the kit would add value for that owner; otherwise not. Personally, I think its a neat addition to a WW II jeep and like it for possible radio installation and because its not seen too often in WW II jeeps. If you are insuring your jeep for replacement value, I'd add $3,000 as the cost of replacing the W7 kit with another one. Realize it could take years to find and acquire all the little parts and pieces of the W7 kit. Hope this helps you a bit.

[44MB]

Hi Fred
Thanks so much for your most informative post. I have had the jeep for a few years and I never really thought much about the originality of its 12 volt set up until now - in fact - TBH I alway did think that being 12 volts it must have been a post war modification - as did others who saw it. I never knew they used 12 volt jeeps in WWII. I am in the process of getting ready to restore the Willys over the Winter so I will take all the more care of the kit now that I know a little more about it.

Thanks again for all the details guys. It all really is very much appreciated.

Andy

[Mark Tombleson]

I know I have been over the 12v before... just some additional information... and a few serial numbers.

Wow, look at that 12v battery!



And... look at this setup with a cowl mounted battery!



As I have noted before 12v tests were done on the MB and GPW.

There were to be 2 vehicle of each type (4) to each of the 4 Army Boards... that would be 32 jeeps (24 MB and 8 GPW).

Armed Forces Board Tests:

26 amp MB generator not tested.

40 amp MB
USA 2095866
USA 2095868

55 amp PTO MB
USA 2095845
USA 2095838

55 amp GPW
no numbers noted


Calvary Board Tests:

26 amp MB (only one jeep tested)
USA 2095859

40 amp MB
USA 2095870
No number for second jeep

55 amp PTO MB
USA 2095837
No second jeep number found

55 amp GPW
USA 20369296
No second jeep number found

Field Artillery Board, Fort Bragg, N.C. Tests:

6 MB and 2 GPWs tested.

26 amp MB
USA 2095862

40 amp MB
USA 2095869

No other USA numbers found

Infantry Board, Fort Benning, Georgia Tests:

6 MB and 2 GPWs tested.

No USA numbers noted or found in photos.

It should be noted that most of the boards chose different generator options.

The Army had 1000 MWO-ORD-G503 W5 (PTO) kits produced and 2500 MWO-ORD-G503-W7 (Ford) kits made.

Let me know if you have one of these jeeps or if I need any corrections!

[Mark Tombleson]

I'm noting the above test with GPW USA 20369296 was similar to but not exactly like the 12v W7 kit made by Ford. The test jeep used a cowl mounted 6v battery and one 6v battery in-between the seats shown in the following photos. Sorry they are weird photos.





The Ford W7 12v kit utilized two 6v batteries between the seats with no modification to the cowl.