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I have a 1952 M38 with engine MC72,042. I have the brass bellhousing "T" in the vent system and yet all the documentation I read notes this only started after Eng# 74,419. Is this possible? Is that engine # not really stamped in stone?

I also had a very old (cut off) piece of 3/16 copper tube coming out to the transfer case vent. Is it more correct to put back copper or the noted "S" in ORD 9- copper coated steel? Only thing I can find is the alloy copper-Nickel tubing.

I have 4 stamped "M"'s in my frame. The one on the inside of right horn is very hard to see, but the other three are clear. (Lf side radiator support, Voltage Regular support and under the battery support. Is that common? I read that most only have three.

Thank you for your comments!

74419 was the official cutoff. But a test run of the new engine block and fording system was done on a group of jeeps in Jan 52. Also in the field it was not uncommon for a motor pool to standardize their fleets by upgrading earlier jeeps to later standards. You see this done a lot in the wiring harnesses. Since there is no way to marry that engine serial to your jeep serial it may well have been a case of a complete powerplant replacement by the Army or a later owner.

It was common and if you look closely in the ORD 7, 8, 9, s for the Army to use copper for field replacement of factory steel tubes.

The frames were assembled at the frame plant right alongside the CJ3A frames and the Factory as a precaution marked all weld on components of the M38 frame that differed from the 3A frame with an M for military frame part.

Interesting and thank you!
So, I guess its personal preference as to using copper or the available copper-nickel tubing for vent lines?

Is it true that the master brake cylinder works better, if vented? The double baffle type? Thx

They are all vented. The military fording system simply routes the vent air intake up away from any water. If they were not vented the fluid would not feed very long from the reservoir to the piston chamber.

My M38 is Serial # 62,925 4/52 it has the early style motor and bell housing, Go Figure Buzzz

There was a run in Jan '52 with the "late" venting system from MC 51887-MC 51988. I have 51898 and it had the closed bellhousing and remains of the late style vent configuration.

The original copper clad steel tube was Bundyweld. It has a look of a copper wash over bead blasted steel. I suspect the jeeps were originally fitted with the copper clad steel instead of copper due to steels better ability to withstand crushing especially considering the power pack could be removed as a single unit. Bundyweld is still available but challenging to find and pricy. Considering physical durability the copper/nickel tube is durable and easy to work with. I'd prefer it over copper considering its crush resistance. If you plan to concourse show your M38 the CuNi pipe may not please the pickiest judge but if you have a driver it will last your lifetime.
There are some copper tubes throughout the venting system most being high in the engine compartment.

TomM wrote:There was a run in Jan '52 with the "late" venting system from MC 51887-MC 51988. I have 51898 and it had the closed bellhousing and remains of the late style vent configuration.

Tom, I didn't realize you had one of the late vented Jan '52 units. As you and I discussed a couple of years back I have MC51986 from
the same run. Yours being early in that run and mine on the tail end. It's cool to have that part of history documented with our rigs.

My orig hood# is 20927543 and I wonder what your orig hood# is..

Our Jeeps probably "met" in Toledo years back

EDIT: the hood# was incorrectly posted as 208, edited to 209. RG

Hi Rick,
The hood # on mine:20928544. Big difference! But no doubt the rigs probably came off the line together. Hoods could have been switched on mine considering it has an RMC engine. But there were plenty of holes drilled for the hood blanket, power plant heater, personnel heater and arctic top that all spells the parts were together for part of its '52-'62 service when it surplused out.

My bad, Tom. I incorrectly typed my hood#. The 1st 3 numbers are 209
for 20927543. That puts our hood numbers 1001 apart. I have edited my orig post

Plus your hood numbers are backwards. Tom early serial / late number & Rick late erial / early number. I don't have any survey forms on file for your two jeeps either!

[quote="wesk I don't have any survey forms on file for your two jeeps either![/quote]
I remember submitting the survey form back in 2010 when I first joined.
Will be happy to resubmit. (I wondered why my jeep wasn't represented in the d-base).

Shoot me the form and i'll resubmit asap..