hello everybody,
i'm glad to inform you that my nightmare is over.
The oil increases because the fuel was contaminated by a very little part of Diesel. I discover that the truck tank that brings to us the RON95 gasoline is usually used to carry Diesel (10'000 ltrs tank capacity). When they ( the "smart guys") fill the truck tank with gasoline (1000' ltr) , they simply don't care to wash the tank from the Diesel. There' also a remaining of diesel in the truck-tank that they didn't drain before refuel the truck-tank with gasoline. The result is the delivering of a mixture of 1000 ltr of gasoline and 100 ltr ( or more ??) of Diesel. Now, after we changed fuel supplier, cleaned our tank, changed the oil engine the problem disappears.
This was my experience that i wanted share with you, and i thank you all of you for your help.
marry christmas ! Buon Natale !
Leonardo
Nice to know info. I had never heard of the diesel fuel issue before. That said I don't know of anyone that had diesel in the fuel.
Thanks for sharing and getting back to us.
Roger Lee LSRM-A & Rotax Instructor & Rotax IRC Tucson, AZ Ryan Airfield (KRYN) 520-349-7056 Cell
Hi all, I'm having the same problem and looks like here, in northern Italy, I'm not alone. I've heard that there's a sort of "epidemy" of fuel to oil transfer and despite many hypothesis on the outcome, no one has isolated yet a root cause for this problem.
The diesel contamination of fuel used to be one of the favourite hypothesis but at my airfield this has been ruled out after having completed the chemical analysis of our fuel (we have a gas pump in the airfield and all aircraft based here use that fuel). The fuel looks perfect with no trace of diesel inside but, despite that, from time to time, we have aircraft exhibiting the issue of oil level incresing due to fuel being transferred into oil.
At the moment we have four aircraft affected (2 high wing and 2 low wing) 3 of which are powered by the 912ULS and one of which is installing the 912UL.
As I said the problem is not always present. After an oil change restoring the level, it is possible that the aircraft flies several hours before experiencing again the issue or it is even possible that, within a single flight of 30 minutes the oil level increases well above max level.
The only common cause seems to be the temperature as the issue started surfacing with the first cold temperatures typical of north Italy wintertime.
Any help will be greatly appreciated as there are really many engines that are now suffering from this issue.
I've never experienced this with our 914s, so I has to find a link to educate myself on some possibilities: http://forums.iboats.com/showthread.php?t=158085
Good Luck!
-Daniel Grotte
References
JB, (2005, Apr. 2). 4Stroke “Making Oil“ by Willy B. Wright [Msg #1]. Message posted to
http://forums.iboats.com/showthread.php?t=158085
Thank you very much Daniel. It has been really an interesting reading although I doubt that this explanation fits my case as both my oil temp and CHT temp are constantly in the 100°C zone so this kind of contaminant should "vapour out". :dry:
I'll keep looking for an answer.
By the way, today, I've extracted 1 liter of oil form the bowl and replaced it with 0.8 liter of fresh oil to see if the situation improved but, when I run the engine, even if I jept it running on the ground until the oil temp was 80°C I kept having oil pressure fluctuations with values going from 3 bar down to almost 0 ad back. Thise fluctuations came in the form of "kicks" of the oil pressure needle as if there were air or vapur bubbles coming through the pump making it cavitating. With the throttle wide open, I've seen the pressure dropping almost to 0.5 bar and reducing it it came back to about 2 bar. :blink:
I definitively need to have the engine checked out :(
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