Need Help Locating Date Code on M38 block

[GAwillysM38]

Trying to determine date of manufacturer (month/year) on my M38 engine block, is there a date code cast into the block?

It is serial number MC 51027 above water pump, block casting number 641087-1-W-12-A-N1-CR-N2
Head casting number 800376
riveted rebuild tag from Schwaeb Gmuend Ordanance Maintenance Depot dated 22-10-56
Series 3 transition block with:
Series 3 features: No reinforced rear flange
Series 4 features: 2 freeze plugs, no clock cast

Any info would be appreciated, thanks

[wesk]

Those without the clock have the day/month in the casting on the left (driver's) side for the casting date. Check the block's lower edge at it's mating surface with the oil pan at the rear end for an assembly date. Not all will have one there. Otherwise only a rough guess can be made based on engine serial alone since an unknown number of engines were built under each contract for spares and the serials run consecutively weather the engine went into a M38 or was shipped to the Army as a spare. No one to date has produced any factory accounting so we can interpolate approximate issue or installation dates, In your case since the engine was overhauled at an Army depot it is a good bet the engine was not your jeep's original engine.

The highest engine serial I have a record of is RMC126145. Keep in mind that all M38 engine serials are sequential starting with MC10001 in 1950. Makes no difference if it was a MCXXXXX installed in an M38 at Willys or a RMCXXXXX new factory spare engine shipped under a contract.

That means we have a total of 62,328 M38's built. We have a total of 116,144 MC/RMC engines built.


This series 4 block was cast Jan 19 of some year.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

[GAwillysM38]

Thanks for the great info and engine production history, I appreciate it