wrote:

Lycoming apparently recommends operation at 65-75% for the first 50 hours
"or until oil consumption stabilizes." This is to assure proper piston ring
seating. They also recommend use of straight mineral oil during this
period, and we plan to run on Aeroshell 50 weight mineral oil. Anybody
suggest otherwise?

That was the recommendation for breakin of my O-320 when I bought the Maule. It had
1.6 hours on it by the time we finished the factory demo ride, and we put 10 hours on
it coming home. We made the first half of the trip at ~65% power and the last half
nearer to redline. Oil consumption had apparently stabilized at 25 hours, so I
changed to 15W-50 Aeroshell at that point. Still runs great and uses little oil after
500 hours.

Any thoughts from the
group on oil selection for general (after break-in) operation?

I run multigrade for two reasons. I want the Lycoming additive that Aeroshell has,
and I don't want to be changing oil weights when the seasons change.

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.