Early or Late?

Trip · Post by **Trip** » Thu Apr 12, 2018 9:02 am

From everyone's research is an M38 with a serial number of: 36832 considered to be an "early or late" vehicle?

Charles

Post by **wesk** » Thu Apr 12, 2018 9:22 am

If one must decide on a point to call the dividing line then 1951 was the end of early and 1952 was the beginning of late. This places the transition at the initial experiment and subsequent move to the later engine 804380 and the later fording system. So your serial would be an early model.

I personally use a three tier system with [Early] Sep 1950 MC10001 thu May 1951 MC20XXX, then [Mid] May 51 MC20XXX thru Feb 52 MC53262, then [Late] Feb 52 MC53263 thru end of production Jun/Jul 52 MC 72329.

Trip · Post by **Trip** » Thu Apr 12, 2018 9:37 am

So if S/N 36862 is an early model, am I correct is saying it would not have left the assembly line with a fording system, which my current project shows no signs of.

Thanks Wes.

Charles

Post by **wesk** » Thu Apr 12, 2018 9:55 am

If you research the fording system thoroughly you'll see that all M38's left Willys with a fording system. There is a point where the system changed dramatically from the early fording system to the late fording system and that was officially at MC53262 Feb 52.

However there is one small glitch in all of this. The new engine casting 804380 along with it's associated bell housing made a test appearance for a short production run MC51887 thru MC 51988 Jan 52 that I believe included the late fording system. The ORD 9 doesn't offer this info. Also the new 802380 casting was incorrectly introduced in Jan 52 because even though the blueprint changed the folks erred and left the old 641087 casting number on the new style block. It was like this till June 52 before the 804380 numbered blocks hit the line.

Here's the new 804380 casting with the wrong 641087 number on it

Here's the 804380 casting with the correct number on it.

4x4M38 · Post by **4x4M38** » Thu Apr 12, 2018 12:39 pm

Then the fun begins.

MC11481 as purchased, in rough ranch condition in 2014,
had an 804380 block and corresponding rear plate and later
bell housing. A rebuild plate from Pueblo Ordnance Depot
indicates that engine was rebuilt in 1955.

Did they change the fording ventilation system over to the
latter one or only the lines necessary to make the newer
motor installation work?

We will never know.

Somewhere between 1955 and now Bubba struck.

radtech · Post by **radtech** » Thu Apr 12, 2018 8:27 pm

My father told me that the USAF removed the fording systems on M38's between 1956-1958 and at the same time changed the bell housings and starters to the late ones.

4x4M38 · Post by **4x4M38** » Thu Apr 12, 2018 9:17 pm

You’d have to change the block as well to match the later bell housing, iirc.

What would be the benefit of swapping all that equipment, particularly if you
removed the fording equipment?

Interesting.

Post by **wesk** » Thu Apr 12, 2018 11:03 pm

By late 1953 the Army had given up on Fording Jeeps. The Air Force was never interested in Fording jeeps at all. That only left the Marines & Navy who still installed fording kits long after Willys quit production of the M38A1 with them.

The other issue was parts. In the majority of cases where a later part will easily replace an earlier production part the Army & Air Force just quit procuring and stocking the early part. This forced the Army & Air Force to install later parts when replacement was needed like bell housings. Transitioning to the later bell housings across the board helped with other parts. IE the Army & Air Force could now only need to stock the late starter for the M38/M38A1/M170.

Since no motor pool records followed these jeeps to their civilian life it is impossible to ascertain when any upgrade in parts occurred unless you were the first civvy owner and picked it up at the base where it was surplused direct from the military.

4x4M38 · Post by **4x4M38** » Fri Apr 13, 2018 10:47 am

In my case the POD Base rebuild tag is affixed
to the block. Which has been decked of course...

I can’t remember Wes. Can you install the later
bell housing and plate on the early block or is it
the other way around?

Post by **wesk** » Fri Apr 13, 2018 10:56 am

In my case the POD Base rebuild tag is affixed
to the block.

Again that is a nice touch but again there's no proof that engine was in that jeep the day it left the military. Unless of course you drove it off the base with the newly minted SF-97. That engine itself could have been a surplus piece on it's own that ended up finding your jeep while it was already in civilian hands.

Can you install the later
bell housing and plate on the early block or is it
the other way around?

You can make them fit either way. However when the engine is the late 10 bolt rear and you try to use an old bell you must grind some metal to see the timing mark on the flywheel.