Single Piston 4 Ring Set for Deutz Fits Allis 2233074One New Aftermarket Replacement Standard Piston Ring Set for Deutz Fahr (Deutz Allis) FL912 Engine This standard (STD) 4 ring set services a single cylinder of the Deutz FL912 air cooled diesel engine, commonly found in a wide range of Deutz Fahr and Deutz Allis tractors. The set includes two compression rings and one oil control ring, sealing combustion gases and controlling oil consumption to keep the engine running at factory specifications.