The benefits of AD (Ashless Dispersant) oil go a long way.

General Automotive oil, uses oil, which has ash added into it. SAE, and automotive manufacturers claim it is cheaper. But not really...

They want you, as a "misinformed" and "stupid" automotive enthusiasts to put it into your car, not knowing it's true purpose.

Ash oil or your common automotive oil, is used to "not prolong" engine life. In fact, more often than not, it probably shortens engine life.

So here is my basic theory...

Ashless Dispersant Oil, or AD as it is referred to in Aviation, is the "standard" when it comes to reciprocating engines. Why? Well, the main thing is liability.

The FAA dictates that all systems must be redundant, (aka safe a possible). No one certainly wants to see someone fall out of the sky while they are flying their plane, due to mechanical failures.

So, if the FAA mandates reciprocating engines "MUST USE" AD oil, than I say, why in the "HELL"(excuse my somewhat harsh language) are we using it in our cars? Well the answers seem to describe themselves(read my above statements.

Here are some of the main benefits of AD oil:

-1) Possesses a washing action that removes particles, sludge and varnish.

-2) Dispersants keep contaminents from attaching to each other and forming large deposits.

-3)Higher flash point and higher viscosity index number.

-4)Better range of lubricating characteristics.

In theory, this:
Reduces the possibility of:
-Contaminants forming in oil passages.
-Piston Ring grooves from forming deposits.

Automotive oils simply cannot stand up to the loads demanded by aviation, which is a reason why I wonder, if anyone would be willing to experiment with a Renesis by trying it.

The AD oil willl appear more dirty, during the oil changing process(but that is because it's working better).

For you new Rotary enthusiasts, and us old-time folks, or general car enthusiasts we all know that:
Time+wear=engine life.

Carbon deposits within the rotary chamber, more specifically, along the Apex seal grooves and springs are generally what plays a factor(although not a total factor) in effecting Rotary engine and Reciprocating engine life.

The cost, surprisingly, is the same.

More info:
http://www.lanclube.com/Exxon_Elite/Exxon_Elite_20W50.html

http://www.swaviator.com/html/issueja02/Hangar7802.html

http://www.sacskyranch.com/faq_oil/FAQ00006.htm

Choose your brand:

http://www.sacskyranch.com/faq_oil/FAQ00006.htm

15W50 is about the lightest I can find.

Look at the price simularity:
http://www.sacskyranch.com/acatalog/Sacramento_Sky_Ranch_Exxon_Elite_222.html

Just remember however a 20W50 is a thicker oil, the 20 weight oil can operate as low as (0*F) and the 50 as hot as (210*F).

Rotarys run hot, and need great lubrication.

Be forewarned however, I am not by anymeans rich. So if you blow it up, it's your own fault. Simply a discussion of whether it would or would not work.

Just something to think about.
:)

Now, let's discuss

You say the ad oil has a higher flash point. You want the injected oil to burn and burn clean in a rotary. That is why 2-stroke ashless formulations would work best for injecting in the motor.

Originally posted by TurboSE
You say the ad oil has a higher flash point. You want the injected oil to burn and burn clean in a rotary. That is why 2-stroke ashless formulations would work best for injecting in the motor.

Yes, an engine lubricating oil should have a high flash point, so that the vapors it gives off can withstand the high temperatures encountered within the engine.

One more thing to add:

During break-in it would probably be best to start with striahgt mineral oil.

It aids in quicker seating of the seals.

After you're finished with engine break-in, then go to AD oil.

The properties of petroleum-based oils

Dispersant

Dispersant action is the property of an oil that prevents the sticking together of carbon-based particles thereby keeping them in suspension. This characteristic inhibits the settling and depositing of carbon on engine parts and prevents sludge from clogging oil passages. Sludge is a mixture of oil, carbon, water and byproducts of combustion.

Ash

Automotive engine oils contain metallo-organic compounds of calcium, magnesium and zinc that serve as detergents and anti-wear additives. When exposed to the high temperatures in a combustion chamber, these additives burn and form a metallic ash deposit on spark plugs and exhaust valve stems. If used in aircraft engines with their relatively high oil consumption, these ash deposits would tend to foul spark plugs and prevent exhaust valves from closing. Ashless aircraft oils use more expensive non-metallic additives to perform the same function.

Viscosity

Viscosity is the oil's resistance to flow or its "thickness". The viscosity used depends on engine design and ambient operating temperature. 80 and 100 grade oils are normally used at low to medium ambient temperatures while 120 grade is used at high temperatures. Most radial engines use 120 grade.

http://www.wearcheck.co.za/sharedhtml/flyerissue3.htm

This seemed to me to be a telling point from www.swavaitor.com

"7. Automotive oil should never be used in an airplane engine.
The most important reason not to use automotive oil in an aircraft engine is the number of additives in it that are designed for use in water-cooled engines operating within a certain range of temperatures and pressures and at constantly changing levels of power. Aircraft engines are air-cooled and operate under an entirely different set of parameters. "


Would not the converse be true, i.e.,

"Airplane oil should never be used in an automobile engine."

for the same reason mentioned above?

Originally posted by Elevation8


Yes, an engine lubricating oil should have a high flash point, so that the vapors it gives off can withstand the high temperatures encountered within the engine.

Huh? what do you mean by vapors have to "withstand high temperatures.."?

the air-fuel ratios are dropping down to around 12-1 starting somewhere abov 6k, dont remember exactly where though
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I would like some more thoughts on AD oil...some of the additives in put in dino oil only benefit piston engines...lets revive this discussion

Does this type of oil have something to do with planes in WWII? Was this type of oil used in the superchargers of these planes? I rememer hearing something about this, correct me if I'm wrong...

FS

Iknow this thread is seriously back from the dead but anyone? RG for instance

I was under the impression that aviation oils are not based on hydrocarbons but on esters... Would not freeze, be of better quality (i.e., viscosity index), stable at higher temps (no deposits), etc.
Now, the old rotary engines were avoiding the synthetic oils because of seal issues... but the actual damaging chemical from synthetic oils was the ester used in small amounts to promote solubility of other oil additives in the synthetic base stock.
So I would be very scared to put a full aviation oil in a rotary engine. I would better use a higher vis oil grade (5W-40).... but for now I stick with the dealer oil changes. I do use premix - high RPM motorcycle 2-cycle oil, 1/600 dilution in gasoline.
Just my $0.02