Here's a reference to the lawsuit:
http://www.prime-mover.com/Engines/Marvel/index.html

And if you have valve train problems, like lifter spalling, sticking valves,
and premature guide wear with your Lycoming, this may explain why:

http://www.prime-mover.com/Engines/Marvel/tbo3.html

Take your time and read it all and study the diagrams showing Lycoming's
obsolete mushroom valve lifter bodies.

Sometime back we had a discussion about which valves run hotter ---
Lycoming's or Continentals. Most people were surprised to learn that even
with sodium-filled exhaust valves and higher oil pressures, Lycoming valves
and guides ran hotter. These studies may explain a reason why.

If you run a Lycoming O-320 or O-360 and find that the even cylinders
(pilot's side) enjoyed better valve train wear than the odd cylinders
(co-pilot's side), these articles may explain why.

Lycomings are still great engines, just need to be brought into the 21st
century.