Deciphering casting and serial numbers

[76291]

CJ-2A 43935 is the engine serial number. Can someone give me a year?

Casting number: 638632 CO -OR N2
WS

As its stamped on the block. Any ideas on this?

[sjalbert]

Late 1946. Should be set up for gear driven timing.

[76291]

Thank you.

[dpcd67]

The number is the block part number. The CO is cobalt. CU is copper. The CR is chromium. The W is Wilson Foundry; the NI is nickel. Sometimes they will have a N2. Must mean more nickel.

[lowenuf]

Late 1946. Should be set up for gear driven timing.

Incorrect.....

it is a 1946, but will be a chain driven motor....

the change to gear did not take place until #44,417.....

[dpcd67]

1946 CJs started out at serial number 12000, and ended at 83000; rounded off.
So the cutoff for the chain drive at 44K, was built in July 46. After that, they used gear drive engines. So, saying "late 46"; that would be a gear drive, depending on the definition of "late".

[sjalbert]

I thought that the cutoff was lower. So CJ but mid 1946, not late. Will a CJ block have a casting date?

[Steve Webb]

Very foggy memory but I think a date was on bottom of block where the oil pan covered it near a corner.