Originally Posted by
RatherBeFlying
The majority of engine wear happens during startup.
^ What he said. I use Philips 20W50 in my Grumman AA1 ( Lycoming O 235 ), and Philips 25W60 in my Nanchang Cj6 ( Husoi 9 cylinder radial).
I find that after I switched from a single grade oil I got virtually instantaneous oil pressure after start up vs a bit of wait before the oil pressure started to move.
One of the things that is not well understood is that the principal difference between straight and multi grade oil is that the single grade oil basically has the same viscosity as multi grade oil when it is at operating temperature, that is both will pour like apple juice. However when cold the single grade will be thick and hard to move while the multi grade will still be thin and move easily through the engine oil passages, hence why it reduces engine wear at start up.
I find it odd why so many pilots are so resistant to technological improvements. Multi grade oil is just the next step in the steady improvement of engine oils that started with straight caster oil in rotary engines, moved through mineral oils and then ashless dispersent oils to todays multi grades.
In any case the number one determinate in engine life is regular use. For maximum life the longest interval between flights should not exceed 2 weeks, and please, please don't just run the aircraft on the ground; that is the worse thing you can do to the poor engine
