NEW INFORMATION

I've received a bunch of email questions about these, so I'm providing this additional information. These cylinderes were 'originally' installed as overhauled cylinders. They have had about 650 hours flown on them since then, but I can't say how many hours before they were overhauled. I unpacked two of them this ccccold winter morning to look at them in more details and take some photos. I was surprised to see that the two pistons were marked 'SUPERIOR' inside - I did NOT see any manufacturer markings on the cylinders, either SUPERIOR or LYCOMING. The pistons were marked with the part number 130700, and some other numbers (eg. 35 16 10) that may (or may not) identify the particular casting.

The Cylinders were marked with some other numbers, thought I'm not sure which would be the part number. Numbers included 0A2330, 88732, 73134, and engraved on the cylinders around the base were the numbers W/O 15055-1 and 4-91 CP 85803-03, and on the other W/O 15055-2 and 4-91 CP85803-05.

Please feel free to write with any additional questions you might have, and I'll do my best to answer.

Disclaimer: I'm not a A&P or even a serious mechanic - please keep that in mind when reviewing this information, and bid accordingly.