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Oil consumption during break-in

The purpose of digging up this older thread is to possibly get an update on oil usage on the IO-390 A3B6. Now with users obtaining more hours or new users data. Also wanted to add my observation going from AEROSHELL W100 PLUS to PHILLIPS 66 VICTORY AVIATION OIL 20W-50. I'd been hanging in with the Aeroshell product as it was a little cheaper but more important Mike Busch was recommending especially for warmer climate conditions. My oil usage almost from the very beginning was a steady 5 to 6 hours per qt. I never saw the 20 to 30 degrees drop in CHT even actively monitoring the SD card data via Savoy. Around 100 hours switched from W100 to W100 plus. Ran that till 400 hours and saw oil usage slow reduce to 8 to 9 hours a qt. At 25 hours the oil would appear very dark, and I would change it with a new filter every other oil change. At 400 hours switched to the Phillips product. What was almost immediately noticeable was the color of the oil even at 30 hours was considerably lighter than the Aeroshell product and now the oil usage has popped up to a qt every 11 to 12 hours. I fly a very similar flight profile almost every week and don't believe that is the difference. There have been comments about less oil usage with the Phillips product, but I've not read anything on the color difference. Any input?

Are you burning AvGas or auto fuel? I also run the Phillips 20/50 along with burning auto fuel and I find that my oil stays pretty clean until my scheduled oil changes. I think the fuel makes a big difference in how fast the oil get dirty.
 
I am the original poster on this thread. I am just under 200 hours on my 14A. My oil consumption stabilized at 8 hours per quart around 110 hours. I usually fill to 6 and add at 5 but I have noticed that the usage is not linear. The first half a quart goes down faster than the second.
 
I am the original poster on this thread. I am just under 200 hours on my 14A. My oil consumption stabilized at 8 hours per quart around 110 hours. I usually fill to 6 and add at 5 but I have noticed that the usage is not linear. The first half a quart goes down faster than the second.

That is a sign that your engine doesn't like more that 5.5 quarts. Once above what it likes, it blows more of it out the breather. Suggest you add at 4.5 and not 5. I add 6 quarts at an oil change (3/4 of a qt goes to refill the new filter) and then add when down to 4 or 4 1/4 quarts. Though I wouldn't recommend my approach without truly knowing your consumption patterns and are religious about checking oil levels. Each engine is a bit different, but mine has a min level of 1 qt. Differences are mostly due to the pan configuration. The key is making sure that you can't out fly your consumption on any given flight.

I use auto filters that have anti drainback valves, so always have a qt in the filter. Not sure, but suspect that some of the aviation filters don't have this and let this oil drainback, so need to factor that in to your approach to min oil levels.
 
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Note that some Lyc's have a minimum safe oil quantity of 2 quarts, while some have a minimum safe oil quantity of 4 quarts (e.g., IO-360-M1B).
 
I am the original poster on this thread. I am just under 200 hours on my 14A. My oil consumption stabilized at 8 hours per quart around 110 hours. I usually fill to 6 and add at 5 but I have noticed that the usage is not linear. The first half a quart goes down faster than the second.

I have almost 500 hours on my Lyc TB 390. After initial break-in, my oil consumption was 6-7 hours per quart. However it slowly and gradually improved and is now about 10-12 hours per quart. I can fill to 7 quarts with no noticeable consumption increase - in fact I often do before a long cross country to avoid adding while away. Otherwise, fill to 6 and add at 5 is my SOP. After an oil change, adding 6 will read closer to 5 1/2 after first flight due to filling the empty filter - skews that first consumption calculation.
 
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