Bill Boyd
Well Known Member
All other considerations aside, there stands a manufacturer's recommendation to change Lyc engine oil every 4 calendar months.
I understand dirt &filtration, moisture & operating temp, 100LL & lead buildup, and acidity in the crank case. Oil and filter changes on the basis of hours in operation, with consideration of extremes in operating conditions such as unavailability of unleaded mogas or frequent, short flights that don't bring the oil temp well into the green make perfect sense to me. We don't want to ask the oil to suspend but so much abrasive dirt and wear metals. But I don't understand nor can I easily imagine the chemistry or physics behind a recommendation that oil be changed every however many calendar months it has been in the engine. I have a feeling the answer may be in the mystical word "additives." I will need some convincing. My mindset is frugal, but not closed.
As a pilot who averages only 40-50 flight hours per year, this is relevant to my situation. I want to know what is allegedly happening to my engine oil in the months that I only fly 3 or four 0.3 hour hops around the patch that would argue for changing it with, say, 12 hours or less total time on it. I've never seen an expiration date on a bottle of 15W-50.
What do we know about this subject beyond conjecture and legend / O.W.T.'s?
I understand dirt &filtration, moisture & operating temp, 100LL & lead buildup, and acidity in the crank case. Oil and filter changes on the basis of hours in operation, with consideration of extremes in operating conditions such as unavailability of unleaded mogas or frequent, short flights that don't bring the oil temp well into the green make perfect sense to me. We don't want to ask the oil to suspend but so much abrasive dirt and wear metals. But I don't understand nor can I easily imagine the chemistry or physics behind a recommendation that oil be changed every however many calendar months it has been in the engine. I have a feeling the answer may be in the mystical word "additives." I will need some convincing. My mindset is frugal, but not closed.
As a pilot who averages only 40-50 flight hours per year, this is relevant to my situation. I want to know what is allegedly happening to my engine oil in the months that I only fly 3 or four 0.3 hour hops around the patch that would argue for changing it with, say, 12 hours or less total time on it. I've never seen an expiration date on a bottle of 15W-50.
What do we know about this subject beyond conjecture and legend / O.W.T.'s?