What does the SP at the end stand for on the serial number? Any hints on how to find info on the compressor end? Found no tag as of yet.

SP means special Parts that were installed at the factory for a special application.OM the SNID book says the 2S went in production in 1945 and the D339 34B started production in 1955.Don,t know about the compressor.

Hi SJ,
Don't know what to believe as I saw an owners manual listed for the D8800 Diesel Power Unit 2S1 dated 1943 in the Cat Legendary Literature list:confused:

OM, it seems no two books show the same info.do they it seems on subjects but I know one thing, that was my first year in high school (1943) been a long time ago and my late sister graduated that year from HS.My late younger brother and I were doing the farming as dad was working in a defense plant as the WWII was going on then.He got rid of the horses and got us a Massey Harris tractor to work on the farm.We put in long hours after school and got up early mornings to do the chores at the barn.

Hi Team,
here is a scan from a Caterpillar Technical Bulletin---Model ID of Non-current Engines--Form No P717-15190 Date 01-15-57.
Hope This helps.
Cheers,
Eddie B.

Thanks edb,
That's a good one:)
Got anything that breaks them down by years?

HI OM,
sorry that is the best I have, in fact I believe it is the only sheet I have seen with days and months for end of production, most articles give year only as start and finish of production and there are few sheets with S/No for year produced for any product as you are aware.
This sheet also covers Marine and Electric sets.
Cheers,
Eddie B.