Originally Posted by
horizon flyer
Compression makes very little difference to power out. Cam wear makes the biggest difference and a big problem on low usage lycomings due to poor design placement of it on top of the crankcase and according to them the I0360 needs to be flown 40 hours a month to make TBO, this keeps the cam oiled. Even so I am very surprised any 10360 or O360 makes it as such a design mess.
The Lycoming IO360 as used on a Cessna172S is the best general aviation aircraft engine ever made. Florida flight schools run them to 4000 hours, and replace the cylinders every 2000 hours with new ones. There is nothing wrong with rebuilt jugs by the way. Many schools use AvBlend oil additive to stop valves sticking.
I own a Lycoming O320. I change the oil and filter every 25 hours. I always use CamGuard oil additive, and Marvel’s Mystery Oil fuel additive. l fly it most weeks, but nowhere near 40 hours a month. Maybe 40 a quarter, but I still expect my zero timed engine to last indefinitely. Always fly at least once a month, for at least one hour, to keep it lubed up and condensation free.
Camshaft wear is caused by corrosion which forms on the lifters, causing them to pit. This then acts as sandpaper on the camshaft. 20w50 oil stays on a camshaft for about seven weeks, whilst SAE 40 or 50 lasts about five. 5% Camguard will prevent any corossion forming even in infrequently used engines.
The Lycoming engine design is not a mess. They make a great product. Just realize that an aircraft is designed to be flown. Use it or lose it. It is after all a tool, not a toy.