Carbon in oil filter

paburke

This is a great forum. I have asked several questions over the last few years and have always received very helpful and informative responses. So I have yet another question if you don’t mind. Still flying my 182L. I have the auto gas STC. I began using some auto gas because last year I flew from Tennessee to Alaska and I knew that there would be some places where 100 low lead would be limited or unavailable. I have noticed no change at all in my airspeed temperatures or fuel burn. At my 50 hour oil changes we have noticed no change in my compressions. what we have noted is that since I have been using up to about 40% auto gas I have been having more carbon particulate matter in my oil filter. I am using ethanol free auto gas and I do test it. Is there any explanation for why I would be getting more carbon particulate matter using auto gas then when I am running 100 low lead?

Scott Sherer

Very good question! Let me send this to our A&P Erich Rempert for his comments. Please stand by!

Scott Sherer

Here's a response from our A&P Erich Rempert:

I’ve chewed on this a bit and the only thing I can think of is the UL fuel is washing the carbon into the oil somehow.

But I’ve got to admit that’s just an idea, and I really don’t know the answer-

Blackstone labs might be a great place to call and ask. They can likely explain the correlation better than anyone-

Let me know if you get to the bottom of it! (Always learning!)

~Erich Rempert, IA Consultant 

Mantoga

Quite possible there is more detergents in the auto gas than 100LL. I have used 87 octane non ethanol almost exclusively for 5 years in my O-470r without any detrimental effects at all. My black stone reports do show that the amount of lead in my oil is a fraction of the norm…

melvyn152

Hi Paburke:

How much more carbon particles? Pics? Consistently?

Do you fly ROP or LOP?

Kind regards,

Melvyn

paburke

I will get some photos of the cut open oil filter next change. Averaging 250 hrs per year so it will not take too long. Have been running about 30-40% of each tank as ethanol free unleaded. Have not had the chance to run 100% yet. I fill with it at home, but still using 100LL when I fill elsewhere. I am running LOP. I still lean the old fashioned way, lean until it starts to run rough then richen a bit. (per POH) I follow this on a JPI 730 as well. Have not changed my leaning methods since using autogas at all. Still suprising to me that leaned at 7-10k I am running around 10gph. (IO470)

paburke

https://forums.cessnaowner.org/discussion/comment/6190#Comment_6190

sorry, not IO, normally aspirated non turbo carb 470.