I Don't Buy it
Actually we see plenty of TEL and lead oxide in the oil analysis on automotive engines running 100LL (race and aviation) despite their closer tolerances, plenty makes it past the rings. Some recent work on a high power 930 Porsche running above 1750 EGT on the track showed plenty of lead in the oil after less than 5 hours on the Mobil 1. No ill effects so far. Temperature and piston to wall/ ring end gap clearances seems to make little difference. I've been using Mobil 1 in race engines with 100/130 and 100LL since around 1980. Never seen anything bad happen. Many of these turbocharged engines run relatively loose tolerances because of the high thermal loads and crankshaft bending loads. They are always spotless inside at the end of the season.
If something was going to crater in this Lyco with 400 Mobil 1 hours on it, it would have happened a long time ago IMO.
Works fine if you change often and probably no need if running unleaded. If it scares you, use Aeroshell.
It's always interesting to hear comments that something won't work even though some of us have been doing it for decades. Auto engines and especially race engines have far higher camshaft ramp rates, valve spring pressures, thermal loads, bearing and pin loads than any Lycoming. Funny that Mobil 1 works fine on a 9000 rpm NASCAR engine and a 19,000 rpm F1 engine but for some reason is going to cause a 2700 rpm Lycoming to croak in a few hours. I've heard all the conjecture about it's going to dissolve bearing shells etc... Recommended by Rotax (bike oil) with unleaded fuel as well which also have air cooled jugs.
