John Deere pistons?

[tractorkrum]

Local parts store was moving and there was a new set of pistons on the shelf that was labeled JD B. Numbers stamped in the top are FPA1239P 045 12-15-A, I assume the first number is the P/N, the second is O45 oversize and do not know what the third number stands for. Are these JD B pistons? Is my assumption correct as being 045 oversized? What are these worth? Were there different pistons for different years of JD B's? Thanks for any information you can provide.

 

[fixerupper]

The pistons must be from the aftermarket. I couldn't find that number on the Deere website. Deere piston part numbers start with either a B or AB. If these pistons do fit a B they certainly aren't worth throwing away.

 

[Leroy]

Yes different years used different pistons. Unstyled B use 4 1/4 pistons. 39-46 styled tractor used 4 1/2 low compression pistons but aftermarket high compression pistons for gas were avaible. Late B.s were a slightly larger piston, for get exact size, and could be either low compression for all fuel tractor, higher compression for gas tractor or aftermarket wih even higher compression for higher octain gas for still more power. After market high compression pistons were alao available for mid series B tractors. Then there were the TSC poerw block that had larger pistons with a higher compression . So yes different pistons for deferent years and block and head installed.

 

[Throop]

Per an old post here, it looks like these may be M&W pistons.
https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=jd&th=308422

Rich