Not bad articles, except the old wives tails
Lead is also used to provide lubrication of upper cylinder components such as valves, pistons, cylinder walls and valve guides.
Lastly, we emphasized the im- portance of having updated valve train components in any engine in which autogas was going to be burned. Modern valves, guides and seats are more tolerant of the absence of lead so that they will not burn up prematurely.
engine manufacturers have identified high upper cylinder and valve wear as a problem when unleaded fuel is used during the break-in process.
When an engine cylinder is repaired or overhauled, an owner should be certain that the latest style, high quality valves, compat- ible valve guides and valve seats are installed that are designed for use with 100LL fuel. As an additional benefit of the new hardware, the valve train is more tolerant of unleaded fuel use.
After repairs to cylinders are ac- complished such as grinding valve seats, valve refacing, or installing replacement parts such as valve guides, it is important to break in these new parts for approximately 25 hours with leaded fuel to provide some lubrication before using lead-free fuel.
Then to contradict the statements above
This fuel has been approved for use with certain models of Lycoming engines (including engines that originally used 91/96 octane avgas) and is now being used in certified aircraft in Sweden.
The recent unleaded avgas operations with this specific unleaded fuel have been very promising with up-per cylinder and valve wear. It is important to differentiate this fuel from automotive fuel.
I wonder why that is? Could it be no lead thus no deposits that are abrasive.
Folks when reading these articles
remember not to become part of the OWT's that have almost been killed off, but seem to resurface far too often!