Oil

Tom-D

Tom-D

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Tom-D
What chemical is added to a high detergent auto, oil that is not in Aviation oil.

or to put it a differently, What is the detergent?
 
Typically magenesium sulfonate (or derivatives thereof). In addition to dislodging the deposits, their big function is to hold it in suspension so it doesn't gum up something somewhere else.
 
flyingron said:
Typically magenesium sulfonate (or derivatives thereof). In addition to dislodging the deposits, their big function is to hold it in suspension so it doesn't gum up something somewhere else.
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How is this detrimental to aircraft engines?
 
By definition detergents are metallic. They make ash. At least that's my feeble summary.
 
PaulMillner said:
It forms ash in the combustion chamber that can glow and cause preignition...

Paul
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I understand that it can do this, but how much oil consumption does it require to be a hazard to the little flat engine? when we ran big radials and 5 gallons per hour was acceptable, I could see this happening. but I have engines that use less than 1 qt in 25 hours.
 
Stewartb said:
By definition detergents are metallic. They make ash. At least that's my feeble summary.
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That is the common conception, but how much does it require to be a problem for us?
 
Tom-D said:
I understand that it can do this, but how much oil consumption does it require to be a hazard to the little flat engine? When we ran big radials and 5 gallons per hour was acceptable, I could see this happening. but I have engines that use less than 1 qt in 25 hours.
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It’s not driven by your engine, but by the OEM’s max allowable oil consumption, which for Lycoming and Continental is ~1 quart/hour... that’s a lot of ash.

Paul
 
Stewartb said:
The last time I called an engineer at an aviation oil producer was Phillips. He was very accessible. I suggest you try it. Get your answers and spread information instead of attitude.
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Good luck with that.

Seriously though, I’m a big proponent of the Socratic method, but when people intentionally say misleading things it doesn’t work.
 
Tom... do a lil google search on the subject. A couple of years ago you answer this question. Memory must be slipping pal. ;)
 
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.

Doesn't Rotax disprove this when they use auto no lead fuels?
 
Checkout_my_Six said:
Tom... do a lil google search on the subject. A couple of years ago you answer this question. Memory must be slipping pal. ;)
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Show me where I was told what the chemical was? you trying to spin the subject again?
 
Why does the oil look a lot more clear after a flight than before?? As viewed on the dip stick.
 
Tom-D said:
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.

Doesn't Rotax disprove this when they use auto no lead fuels?
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Disproves what? That aircraft engines are air cooled?

You don't use generic "Automotive" oil in a Rotax either. Or, at least, if you follow the Rotax recommendations you don't.
 
Does the manufacturer recommend (should), or does he insist (shall) that certain oil be used? Or does he demand (must)? The AD on the lighting says it all. :p
 
PaulMillner said:
It’s not driven by your engine, but by the OEM’s max allowable oil consumption, which for Lycoming and Continental is ~1 quart/hour... that’s a lot of ash.

Paul
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Makes sense, the worst engine in the fleet governs what the rest of us must do.
 
JAWS said:
Does the manufacturer recommend (should), or does he insist (shall) that certain oil be used? Or does he demand (must)? The AD on the lighting says it all. :p
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I don't know, You tell me,I asked a simple question and got an answer, Thanks to Flyingron, Now the rest of ya play nice.
 
It has been said many times on this page by more than a few, that synthetic oils have problems with lead in fuel.
next question, why should detergents have a problems with lead?
 
Who cares? Why would you be so ignorant to run auto motor oil in an aircraft engine? I known of none that even hint of using the stuff.
 
My old air cooled, horizontally opposed Porsche 911 ran just fine with automotive oil. Me thinks the answer is in 100LL, not the engine specifics.
 
Hang 4 said:
My old air cooled, horizontally opposed Porsche 911 ran just fine with automotive oil. Me thinks the answer is in 100LL, not the engine specifics.
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I do believe that detergents in oils significantly predate the removal of lead from auto fuels.

I also suspect that your old 911 had an oil filter that could remove the solids suspended by the detergents - unlike many aircraft engines.
 
Hang 4 said:
My old air cooled, horizontally opposed Porsche 911 ran just fine with automotive oil. Me thinks the answer is in 100LL, not the engine specifics.
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My old VW ran great on leaded fuel and detergent oil.
Checkout_my_Six said:
Who cares? Why would you be so ignorant to run auto motor oil in an aircraft engine? I known of none that even hint of using the stuff.
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The better question is Why not, and the only sensible answer is from Paulnillner
 
I didn't respond further because my question answered Tom's first question (what is the detergent and why). Indeed the subsequent answers of the AD in aviation oil was there to suspend the crud without leaving an ash that would form a detonation-causing hot spot in the temps involved in the air cooled engines. AD after all does stand for Ashless Dispersant which is pretty descriptive.

Yes, the non-synthetic automotive oil predates the elimination of lead in auto fuel. There are problems with synthetic oils (remember the Mobil 1 debacle) and leaded fuels.

Note that this isn't too uncommon. You don't use a gasoline engine detergent oil in a diesel either.
 
flyingron said:
I You don't use a gasoline engine detergent oil in a diesel either.
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Oh NO? I'm in big trouble, I'm coming up on 56k in my MH, with 15-40 DELO which is a high detergent oil. says so on the bucket. And Did 156k in my dodge 5.9 with it.

And thanks for getting back
 
JAWS said:
You must not have liked Flyingrons answer. You continued with 6 more pedantic questions.
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At least he had an answer, not a word game.
 
JAWS said:
You (Tom) continued with 6 more pedantic questions.
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Pedantic and Tom are two words that I never thought I'd ever see in the same thought.

Many other descriptors have crossed my mind over the years, especially when I'm reading his frequent misspellings and misuse of words, but pedantic has never been at the fore.

I won't go there.
 
Stewartb said:
By definition detergents are metallic. They make ash. At least that's my feeble summary.
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Detergents are just amphipathic materials (they have polar and nonpolar components in their chemical structure to help suspend grunge). They can be ionic, as in sulfonates, which will have a metallic counter ion or nonionic (i.e. neutral, and composed solely of organic material). The nonionic materials will be completely combustible, leaving little or no residue. The ionic detergents will leave behind some refractory metal oxides (ash) if burned. Ash is a pre ignition problem in an aircooled engine, which burns a lot of oil compared to a watercooled engine. (Larger clearances and oil blowby.) Auto oils typically contain ionic detergents, aviation fuels the nonionic variety.
 
chemgeek said:
Detergents are just amphipathic materials (they have polar and nonpolar components in their chemical structure to help suspend grunge). They can be ionic, as in sulfonates, which will have a metallic counter ion or nonionic (i.e. neutral, and composed solely of organic material). The nonionic materials will be completely combustible, leaving little or no residue. The ionic detergents will leave behind some refractory metal oxides (ash) if burned. Ash is a pre ignition problem in an aircooled engine, which burns a lot of oil compared to a watercooled engine. (Larger clearances and oil blowby.) Auto oils typically contain ionic detergents, aviation fuels the nonionic variety.
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I wish I understood what you said.
 
chemgeek said:
Detergents are just amphipathic materials (they have polar and nonpolar components in their chemical structure to help suspend grunge). They can be ionic, as in sulfonates, which will have a metallic counter ion or nonionic (i.e. neutral, and composed solely of organic material). The nonionic materials will be completely combustible, leaving little or no residue. The ionic detergents will leave behind some refractory metal oxides (ash) if burned. Ash is a pre ignition problem in an aircooled engine, which burns a lot of oil compared to a watercooled engine. (Larger clearances and oil blowby.) Auto oils typically contain ionic detergents, aviation fuels the nonionic variety.
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What kinds of additives are included in some of the application specific oils meant for air cooled engines, such as motorcycle oil or garden tractor oil?
 
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