macrafic
Well Known Member
Background: Just completed RV-7A. IO-360 engine new. Started with 7 qts of oil, with the assumption that the better part of 1 qt would go to the oil filter. At 2.0 (tach)/3.5 (hobbs) hrs, I added a quart of oil. Probably could have waited another 2-3 hrs, as not quite a quart had been consumed. I now have 13.8 (tach)/16.8 (hobbs) hrs and am not needing to add additional oil yet. Maybe another couple of hours? So, in summary, I have 11.8 (tach)/13.3 (hobbs) hrs on this last quart of oil.
CHTs are behaving, but I did not unfortunately record the very initial CHTs at a particular power setting for a current comparison. As a result, I don't know if I have experienced the 50 degree drop in CHTs that I have heard about (as another indication that the engine has broken in).
In trying to summarize the various VAF posts on oil consumption, it seems to be the general opinion that 10 hrs per qt is a pretty decent consumption. Obviously, some are getting less and some more than that. So, I am definitely above that. I have read Lycomings documentation, but they only specify the max allowable oil consumption, not a desirable range. They also only specify a maximum schedule for mineral oil (25 and 50 hrs), with a stipulation that the key criteria is stabilized oil consumption.
So, the questions I am pondering. With so few hours, could the engine already be broken in? The oil has gotten much darker the last couple of flights, so I would like to change it. Should I again use mineral oil or go to standard oil?
Anybody have any other perspectives/thoughts/experiences that I should contemplate as I make these decisions? Any thoughts welcome.
CHTs are behaving, but I did not unfortunately record the very initial CHTs at a particular power setting for a current comparison. As a result, I don't know if I have experienced the 50 degree drop in CHTs that I have heard about (as another indication that the engine has broken in).
In trying to summarize the various VAF posts on oil consumption, it seems to be the general opinion that 10 hrs per qt is a pretty decent consumption. Obviously, some are getting less and some more than that. So, I am definitely above that. I have read Lycomings documentation, but they only specify the max allowable oil consumption, not a desirable range. They also only specify a maximum schedule for mineral oil (25 and 50 hrs), with a stipulation that the key criteria is stabilized oil consumption.
So, the questions I am pondering. With so few hours, could the engine already be broken in? The oil has gotten much darker the last couple of flights, so I would like to change it. Should I again use mineral oil or go to standard oil?
Anybody have any other perspectives/thoughts/experiences that I should contemplate as I make these decisions? Any thoughts welcome.