[N941WR]

In the past there has been a lot of banter about using automotive oils in our Lyclone engines. Reasons not to have ranged from conflicts with the metals in the engines reacting to the oil additives to you will die a death of a thousand cuts.

Since I have an ECi engine, I called up tech support at ECi and asked about using automotive oil in my engine. I guess I?m not really surprised by the answer.

I was told that there was not metallurgical reason for using aviation oil. However, since the engine is air cooled, aviation oils are formulated for the higher temperatures seen in the cylinder heads of our airplanes. I suppose that if you used oil formulated for air cooled engines (Porches, Harley?s, etc.) you would probably be OK.

However, it might turn out to be false economy by saving money on oil and trashing your engine.

Is anyone running auto oil in their Lyclone?

Before any of you start blasting me, I am running Aviation oil in my engine. This is posted for informational purposes only. Operate your engine according to the manufactures specifications, blah, blah, blah.

 

[N941WR]

FYI – Here is what Lycoming has to say on the subject.

QUESTION: Is there really any difference between good automotive oil and aviation oil?
ANSWER: Yes, indeed there is! Don’t ever use automotive oil in your aircraft engine. These oils are now blended for use with unleaded fuels, and the additives in auto oil cause problems in an aircraft engine that operates at much higher temperatures than the automobile engine. We have encoun¬tered engines with holes burned in pistons due to the use of automotive oils that have an ash deposit causing preignition. It seems awfully hard to convince people who have had great success with the oil used in their car that it may not be used in their aircraft engine.
NOTE — Since we have had several questions on fuels and oils, it might be well to mention that we can’t think of a quicker way to void your engine warranty than by using anything other than the recommended and FAA-approved aviation fuels and oils.

 

[airguy]

I guess it depends on what risks you want to take. I fly my 172 about 300 hours a year, well above the norm and change my oil every 50 hrs (also well above the norm). I don't run auto oil, but I very well could, most likely. I run aviation oil, standard grade (not full synthetic multi-weight).

If you're flying 50hrs/yr and changing oil at annuals, you don't want to take chances. Buy the good oil, it's worth the insurance. If you're flying every other day and changing oil every other month at 50 hrs, it doesn't matter nearly as much. The number one enemy of aircraft engines is sitting still in the hangar, not the type of oil in the sump.

Your engine, your call.

In response to Bill R. above - only partly in jest - I'm much less worried about what Lycoming suggests than I am about what keeps my butt outta the trees. Lycoming sells engines, oil companies sell oil - whaddayu think they are gonna say?

 

[SHIPCHIEF]

So far everyone has done what they were told an runs Aviation Oil.
Is there anyone who runs a Lyclone on different oil?
I am not overly impressed with the notion that only Av Oil can safely lube a Lyc engine to TBO and beyond, but consider that the case price of Av Oil is not significantly higher than buying quality oil at the auto parts store, and you can buy Av Oil at the aviator store...
Until someone does the research and has the data points to show success, and presuming the winning oil type has not been reformulated since the test.....

 

[rv6ejguy]

This question came up a couple years ago and there was lots of speculation about all kinds of things. First, Mobil 1 is probably more stable at high temps than any currently available aviation oil and it is certainly capable of operating at any temps involved on a standard Lycoming so that is a nonsense answer.

Second, I've used it for over 25 years in cars, some sitting for years, never seen any cam corrosion issues so I doubt if the cam material in a Lycoming is much different than a Toyota.

Third, I had a PM from a guy with an O-360 who had run Mobil 1 in his engine for 6 years and 1600 hours on unleaded fuel and had no issues, perfect compression and leakdown, never had any issues with the engine. He only used 100LL occassionally on longer cross country trips.

Is it a good idea to use Mobil 1 in Lycoming burning mostly 100LL? Probably not according to Mobil engineers when I asked them myself by email citing the fact that is will not hold much lead in suspension. A possible way to mitigate this is to use Decalin Runup in the fuel. The Military use this product very successfully in their Rotax powered UAVs running 100LL.

What would I run if I flew a Lycoming? Aeroshell. Well proven at Reno in traditional engines running way more power and heat than anyone here on this forum. Aeroshell is very good stuff, heck I used it for 75 hours in my Subaru and the engine didn't blow up! Old myths seem to die hard.

 

[N395V]

I just spent a couple of hours perusing some airboat forums.
Figured if anyone was using auto oil in aircraft engines it would be them.

For the most part (based on number of posts) they are pretty adamant about using av oil for the same reasons cited above. This group used 100LL as fuel almost exclusively. None of the av oil advocates could point to any actual problems caused by using automotive type oils.

There were several airboaters with O-360s, O-540s, and GSO-480s claiming to have used automotive oil for years without any problems. Some used 100LL and some used Mogas with ethanol as fuel.

There does seem a greater propensity among airboaters to use additives such as MMO and transmission fluid in their fuel and MMO in their oil.

 

[bret]

I was told that the Diesel oil like Delo 400 15w40 starts off with a much higher quality base than the car oils, Think about the turbo shaft spinning at 120,000 RPM on a film of oil with the turbine wheel atached at one end at 1300 deg. I have used this oil in 13,000 RPM street bikes, NOS sprayed big blocks, marine engines, and and of course the Cummins powerd Dodge, no problems over the last 20 or so years.
The only issue I have heard was the 100LL avgas will do bad things to the automotive oil or the engine?
Did the oil change from back in the days of leaded gas at the gas station?

 

[BobTurner]

I have seen no comments about the crux of Lycoming's arguement: AD = "ashless dispersant". Automobile oils have "ash", a compound which makes little tiny flakes of metal-like stuff, designed to clean deposits by abrasion. The Lycoming claim is that if an engine is run for long periods of time at the same power setting, there can be areas within the cylinder where the ash will settle out or stick; and then it will act as a glow plug, cause pre-ignition and destroy the cylinder (usually the aluminum piston is first to go). In cars they claim the frequent power changes don't allow the ash to stick or settle out. That's the claim, I have no idea if there is any evidence to support it.

 

[RV10inOz]

Originally Posted by Lycoming
QUESTION: Is there really any difference between good automotive oil and aviation oil?
ANSWER: Yes, indeed there is! Don?t ever use automotive oil in your aircraft engine. These oils are now blended for use with unleaded fuels, and the additives in auto oil cause problems in an aircraft engine that operates at much higher temperatures than the automobile engine. We have encoun?tered engines with holes burned in pistons due to the use of automotive oils that have an ash deposit causing preignition. It seems awfully hard to convince people who have had great success with the oil used in their car that it may not be used in their aircraft engine.
NOTE ? Since we have had several questions on fuels and oils, it might be well to mention that we can?t think of a quicker way to void your engine warranty than by using anything other than the recommended and FAA-approved aviation fuels and oils.



Sounds like warranty department speak to me. Why do Lycoming allow such things to be printed?

Mobil 1 and avgas have shown to be a bad mix. I use it in my cars and it's wonderful stuff. Not in my plane.

Once we have unleaded avgas though......I wonder what holds them back?