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Borescope pictures of my io-390

Blake

Well Known Member
Got 25 hrs of use on my new lycoming 390
On my rv-14a. Using approximately a quart every 4 hours. What do you mechanics think?
 

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I went through the same worries and similar high oil burns on my 390 <50 hours. Borescoped, contacted Lycoming and all told me to keep running hard on mineral oil. I did until 75 hours and it got down to a qt every 6 hours or so, then switch to Phillips. By 100 hours it had dropped dramatically. At 250 hours I am burning hardly any oil at all, less than a qt every 10+ hours. Borescope looks ok to me.
 
Run it. Run it hard. Also realize you may be blowing it out the breather line... How high are you running your oil level?
 
6 qts max

Keeping it around 7 quarts.

Try 6 qts and add a qt at 5. I believe Lycoming says you can run down to 4 no issues but check your documentation. The lack of oil on the belly does not mean you are not tossing it overboard. These angle valve engines seem to use a little more oil than the parallel valve engines. Polling 390 users seem to range from 6 to 10 qts. an hour. Rumor has it that Phillips 20 - 50 helps reduce usage in a 390 but not documented.
 
Run it hard for 75 hrs and continue to use mineral oil. The 390 takes a long time for oil consumption to stabilize. I was initially worried but by 75 hrs. when I switched to multi grade consumption settled down. Now getting 9 - 10 hrs on a quart. I keep the level between 5 & 6 quarts.
 
Both of my RV14As have been burning about 1qt every 6 hours but this varies by the type of flying. In my last long x-country flight, trip to Oshkosh, I was planning on the same oil usage but I used only 3/4 of qt in 10.5 hours of flying and just about the same on the flight back home. Switching to Philips X-country has not made any change in the oil usage.
 
I went through the same worries and similar high oil burns on my 390 <50 hours. Borescoped, contacted Lycoming and all told me to keep running hard on mineral oil. I did until 75 hours and it got down to a qt every 6 hours or so, then switch to Phillips. By 100 hours it had dropped dramatically. At 250 hours I am burning hardly any oil at all, less than a qt every 10+ hours. Borescope looks ok to me.

Borescope looks good. A short taxi with colder engine and 7 pts in the sump affects the usage negatively. It will continue to fall even (as above) when changing to full additive oil.

Carry on . . . .
 
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