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Oil burn rate - IO390

Bavafa

Well Known Member
Just curious to see what others are getting for oil burn/use with their IO390?
Mine seems to be right between 7 to 8 hours a QT and I fill only with 7 QT and add as I get to 6 QT level.
I am throwing some of it out of the breather but not a whole lot
 
I?m getting 9 hours per quarter. I do the same as you, fill to 7 and add when it gets to 6 qts. I don?t see much evidence of oil on the exhaust where the oil breather is but the bottom is getting some oil.
 
Five hours or so...

Right now, planning on the basis of a quart in five hours. I fill to six and add at five. Anything over six seems to go overboard. 73.7 hours so far...
 
I have about 7-8 hours on current oil change and down a bit over half of a quart. Seems to go faster down to 6 then slower. Consumption seems to be slowly going down at about 42-43 hours engine time.
 
Mine seems to be right between 7 to 8 hours a QT and I fill only with 7 QT and add as I get to 6 QT level.

Mine burns through anything over 6qts pretty quick, 7qts is probably too much, try using 6qts as your max and you’ll likely stop seeing the waste.
 
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If your not using Phillips X/C 20/50, try it. Might improve an extra hr or two, mine did.(0-360)
I put cam guard with it. I get about 8 hrs/qt until the oil has around 20hrs on it, then it drops down to around 6/hr., about the time it starts looking dirty. Other oils (Aeroshell 100+) started getting dirty after only about 4 hrs and only got 6 hrs out of it.
 
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measurement variables

Tracking oil consumption accurately takes some specific effort and consistency in recording details, along with quite a bit of flying...

After more than 2000 hours on my 390 I currently fill with 8 quarts and a pint of camguard then add a couple at 6, one more back at 6 and change it at 30-40.

Some long term observations

  • overall I see 6-8 hours per quart
  • reading the first quart down can be deceptive
  • The type of flying can impact the rate
  • Consumption rates at low volumes is higher
  • 8 quarts in the sump is fine with no increase in the consumption rate
  • Indicated oil pressure is lower with less oil and begins to fluctuate below 5 quarts in the engine... at 4 the oil pressure bounces with the slightest bump and is down to 50 psi from a normal steady state of 72
 
Thank you all for providing your consumptions rate and inputs. It seems that 6-8 hr/QT to be the average for the IO390. From what I have learned about Lycoming engine, using some oil is absolutely normal and sign of healthy engine as too much or too little oil consumption indicates abnormal. As for the oil level, my guide is to put as much as possible without getting it to throw out of the breather. One area that more oil level will help is the oil temp, with more oil you will get a lower oil temp. Also type of flying has a direct effect especially if any aerobatic moves are done.
FWIW, I run my engine a bit harder than the last plane, my typical climb is as full power and then lower the RPM to around 2500 for cruise. I wonder running it harder has an impact on oil consumption!?!?!?
 
overall I see 6-8 hours per quart

Similar before adding a case evac system and separator, now closer to 10.

8 quarts in the sump is fine with no increase in the consumption rate

Listen....that was the sound of another hoary myth imploding.

Indicated oil pressure is lower with less oil and begins to fluctuate below 5 quarts in the engine... at 4 the oil pressure bounces with the slightest bump and is down to 50 psi from a normal steady state of 72

Never been below 5. I do see oil temperature creep up below 6 qts, perhaps 5-10 degrees by 5 qts.

Holy cow you put a 390 in a 7? Nice ...

Stephen is my hero. May have more 390 hours than anyone, and runs the snot out of it.
 
Thank you all for providing your consumptions rate and inputs. It seems that 6-8 hr/QT to be the average for the IO390. From what I have learned about Lycoming engine, using some oil is absolutely normal and sign of healthy engine as too much or too little oil consumption indicates abnormal. As for the oil level, my guide is to put as much as possible without getting it to throw out of the breather. One area that more oil level will help is the oil temp, with more oil you will get a lower oil temp. Also type of flying has a direct effect especially if any aerobatic moves are done.
FWIW, I run my engine a bit harder than the last plane, my typical climb is as full power and then lower the RPM to around 2500 for cruise. I wonder running it harder has an impact on oil consumption!?!?!?

“Using oil is normal...too little indicates abnormal.”
OK....interesting....how is that so? Curious...not doubting because if it is written it must be so.
[humor alert]

R
 
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?Using oil is normal...too little indicates abnormal.?
OK....interesting....how is that so? Curious...not doubting because if it is written it must be so.
[humor alert]

R

It was mentioned in a maintenance class I took and I failed to ask the why?
Could it be that it might be absent of enough honing in a cylinder? I am just guessing?
 
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