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Break In Oil Consumption

pilot28906

Well Known Member
I have 8 hours on a new IO-360-M1B and the engine is not burning much (or any ) oil. Seems like it burned maybe 1/4 qt or so the first couple hours but has not burned any since. Should it be burning more at this point? CHT's got close to 400*F first couple of hours but now are around 350-360*F. It's ready for an oil change so just wondering if I should stay with the straight mineral oil until the next change? Most of the flights have been close to an hour with the longest being 1.5.

Thanks for your input.
 
Looks like it is running well. You will have a better trend as you put more hours. My IO-360-M1B burned about 1qt every 9-10 hours which I believe is the common rate.
 
Break in

It would be safe to assume that the break in process is likely not complete at 8 hrs. Definitely will not hurt anything to run mineral oil for awhile. If it were my engine I would be very pleased with what you are seeing and would run mineral to 50 hrs with a intermediate oil change at 25. Check all screens and filters at each change.

Don Broussard A&P, IA, ATP
RV9 Rebuild in Progress
57 Pacer
 
As Mike Busch states, break-in hours depends on cylinder type. Chrome cylinders take the longest (50+ hrs) while nitride hardened take the least (typically < 5 hrs).

Breaking Good video
 
It would be safe to assume that the break in process is likely not complete at 8 hrs. Definitely will not hurt anything to run mineral oil for awhile. If it were my engine I would be very pleased with what you are seeing and would run mineral to 50 hrs with a intermediate oil change at 25. Check all screens and filters at each change.

Don Broussard A&P, IA, ATP
RV9 Rebuild in Progress
57 Pacer

+1

complete break in is usually longer than the time for CHTs to drop and oil consumption to stabilize. Best to use mineral or any oil with out friction modifiers, such as xc 20w50 for 50 hours. AD additives are fine for breakin.

Larry
 
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