On the 550’s, even though the quick drain looks like its in the lowest part of the sump, based on angles, you can have a significant hunk of oil left after draining. Maybe up to a cup or so? That lower section does a good job of catching errant parts floating around too. Black oil after 10-20 hrs after change,,, ring issues.
Your oil consumption numbers confusing……..
Consumption up after each change? Not sure i reading correctly. One qt in 8 hrs?? thanks
carl
When we do the 50hr check, I run the engine up to bottom of green arc (oil temp about 90F) and then when it is drained out, I wait 1 minute before taking the sample for analysis (partly to shift any dirt inside the tube) and then we let it run as we do the plugs, oil filter, etc, which is perhaps an hour.
Hi Carl,
after an oil change i notice that over time the consumption seems to go up with time until the next oil change.
then it starts again at 8 hours / qt dropping down to about 5.5 – 6 hours / qt when she is on about 25 hours, then I change the oil
Yes I think that is fairly common.
I would suggest filling it to a slightly lower point on the dipstick and seeing if the ‘consumption’ reduces. My bet is that you’re blowing quite a lot out through the breather, replacing that which you’ve blown out, and then blowing that out!
I think you may well be right
the underside of the ac is definetly a bit oily..
I had a crankcase pressure test as well just for good measure and that was fine so it is pointing to the breather….
thanks Graham and Peter
J
On the IO540, anything above 10 goes fairly quickly out of the breather pipe. I have no idea why they recommend 12. I fill with 9 and keep it between 6 and 9. We had a thread on this before where the TCDS for the engine was referenced and that tells you the actual minimum level, which is about 2 (in level flight).
I fill with 9 and keep it between 6 and 9.
I used to do the same when I owned TB20. I tried few times to fill more just to see what would happen and it was wasted immediately. IIRC the consumption on average was 1 qt every 6 hours and it depended on duration of the flights – longer ones consumed more while several consecutive shorter ones consumed less.
I read that the max oil capacity is to allow use of a worn-out engine – burning oil. Not something normally done, but the military might require it.
Engine development testing, oil consumption hight at end of life, sump capacity set to allow specified engine run time in that condition.
Emir wrote:
I used to do the same when I owned TB20. I tried few times to fill more just to see what would happen and it was wasted immediately. IIRC the consumption on average was 1 qt every 6 hours and it depended on duration of the flights – longer ones consumed more while several consecutive shorter ones consumed less.
We have the same experience with (I)O360 engines, but of course the figures are 6 and 8 qts, respectively. The recommendation in my club is to fill in a whole number of quarts until the level reaches or passes 6 qt, but never more than that.
