I’ve owned my C182 since 1990. It came with a Gold Medallion Factory Reman (zero time) with 250 SFREM. O-470R. Around that time 80 started going away. I tried a steady diet of 100LL but ended up with fouled bottom plugs about every 50-100 hrs no matter how aggressively I leaned. The engine is a cold blooded engine with CHTs in the low 320s summer and low 300s winter, even in aggressive high powered climbs it was hard to get CHTs above 360.
I switched to ETOH free mogas at 335 hours SFRM, no appreciable difference in performance, CHTs, EGTS or fuel consumption. The engine ran to 2750 hrs or about 1250 past its 1500 hr TBO. The overhaul was due to increased nickel in the oil and Cam spalling. It ran nearly exclusively on mogas. At teardown, the overhauler told me I’d probably trashed the entire engine. Two days later he said other than the cam, the engine was immaculate.
I flew between 150 and 300 hours/year at altitudes between 2000’ MSL up to 15,000. Never had a whisper of problems. The engine is now on its second run, at 1750, 250 past TBO running mostly on mogas, which is getting harder to find, a smattering of time on Swift 94UL, and the remainder on 100LL. It flies on the average twice a month on 5.5 hour legs, the oil analyses are clean with no wear metals and more lead than I’ve seen in a long time, mainly due to my second base having only 100LL.
So, since the 1990s I’ve run around 4,250 hours on this engine, one overhaul, which might have been avoided if camguard was used.