My IO-550 seems to “like” 7 quarts, tending to blow out that 8th quart fairly quickly like others have commented. However, I have experienced periods wherein it held at 8 quarts - I’m thinking it may have something to do with the type of flying and maybe the conditions flown in, i.e., touch and go’s on a 95 degree day versus relaxed cruising in cool WX. Personally, I don’t like to operate with fewer than 6 and try to stay between 7 and 8 quarts.
During my engine break-in period, I did call Teledyne Continental and ask this question among others. They said that they recommend 8 quarts. For liability reasons, I reckon that’s the only response they could provide. They did bring up a good point though: the extra oil provides an additional safety factor/margin in the event of an oil leak. That extra quart, or two, may very well keep the engine running until a suitable landing place is reached.
Dana Westphal
Legacy RG N97DW I ’t “Built over Geologic Time, but Flying at Warp Speed”
Subject: [LML] Optimum IO-550 oil level - zero oil pressure event
So, again, what are you IO-550 guys using for normal oil level, and when do you add oil? What oil stories can others tell?
Curious Fred