Aviation's Version of Mobil 1 EP

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I have a friend that runs areoshell i think it's 15w 50. He is an a and p mechanic but he runs this in his suburban. How is a piston engine add pack different from an automotive add pack? I'm not sure running aeroshell in a suburban is a good idea.
 
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dkryan

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Originally Posted By: spasm3
I have a friend that runs areoshell i think it's 15w 50. He is an a and p mechanic but he runs this in his suburban. How is a piston engine add pack different from an automotive add pack? I'm not sure running aeroshell in a suburban is a good idea.
That's a good question, Spasm, and while I could take a wild *** guess at an answer, I'll defer to Molakule and those more knowledgeable. I would agree that running Aeroshell in a Suburban is not a good idea.
 
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Something to do with lead in av gas... the oil has additional additives to deal with the lead blowby/ contamination. Don't think it would hurt the truck engine in any way... Both applications are piston engine, so very similar in basic lubrication needs.
 
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Originally Posted By: geeman789
Both applications are piston engine, so very similar in basic lubrication needs.
I thought aviation oils did not have any detergents.
 
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The Mobil Jet 387 referenced in the opening post is a 4th generation jet turbine engine oil and is completely different from piston aircraft engine oil. Jet turbine engine oils are based entirely on polyol esters (93-96%) and contain mainly anti-oxidants, anti-wear, and anti-corrosion additives, and sometime a dash of anti-foam, EP, and other additives. They have no detergents, dispersants, or organometallic additives. They are very light oils, thinner than 0W-20s. Piston aircraft engine oils are much thicker, often XW-50s, and are based on mineral oils, sometimes blended with PAO. Additives are mainly dispersants, anti-oxidants, and anti-corrosion with no organometallic additives. Neither are suitable for automotive engines. They contain no detergents or ZDDP, and the jet oils typically have a phosphorus content of 0.18-0.24%. Tom NJ
 
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Originally Posted By: dkryan
Originally Posted By: spasm3
I have a friend that runs areoshell i think it's 15w 50. He is an a and p mechanic but he runs this in his suburban. How is a piston engine add pack different from an automotive add pack? I'm not sure running aeroshell in a suburban is a good idea.
That's a good question, Spasm, and while I could take a wild *** guess at an answer, I'll defer to Molakule and those more knowledgeable. I would agree that running Aeroshell in a Suburban is not a good idea.
Unless he's getting the Aeroshell at well below cost, the economics alone make it a bad deal. I saw some Aeroshell 15W-50 on CL at a killer price a few years ago and thought about buying a couple of cases to do a few runs in my old BMW followed with a UOA, just for grins. What I was able to find about the add pack of this oil convinced me that this wouldn't be a wise idea. I wouldn't run any av oil in any road vehicle.
 
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I worked with a fellow A&P years ago that was using Aeroshell 15W-50 in his Chrysler that had over 250,000 miles on it. He was completely convinced that if this oil was good enough for the Continental O-470 in his airplane, then it was completely suitable for the 2.5l in his Lebaron. Even way back then I knew this was not the best idea, but he had a quarter of a million miles on his engine, who was I to argue. Not all of those miles were on aviation oil but he had been doing it quote "for years" and he drove about 50 miles daily each way to school so I have no doubt it was a significant amount. I wanted to have the conversation and try to convince him AeroShell, fine oil that it is, was not appropriate for his car, but I knew all he would do is pop the hood, point at the engine, then march me around and point at the odometer. He wasnt the type you wanted to have a debate with, no matter how wrong he was and how correct you are. I moved on and lost touch with him, but it would have been very interesting to see the interior of that engine....
 
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I suspect that the inside of that automotive engine was quite clean. AS 15-50 is partly PAO and it does a great job keeping aircraft engines clean. It also works well on flat tappet engines. It does not use ZDDP, however the add pack does contain EP additives. I suspect the oil will work just fine, with the exception of very cold weather ops. As it's quite thick in sub freezing temps.
 
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My first thought was that any oil changed on fifty hour intervals should keep any engine clean, since that would only represent 1.5-2.5K miles of driving. I thought a bit more and realized that wasn't a valid comparison. Even a very abstemious piston single operated at low cruise power settings will burn through more than 350 gallons of fuel in fifty hours and that fuel contains plenty of lead. In contrast, our least economical car will use only about a third of that in fifty hours and it uses a fuel containing no lead. The aircraft will also cover at least 6K miles in those fifty hours, even if it's a slow one operated at low power settings. Maybe AS 15W-50 would work well in a car engine for which such a thick oil is recommended, like my old BMW? Maybe the next time I see some for cheap, I should give it a few runs, just for the sake of satisfying my curiosity? Incidentally, when you wrote "EP additives" did you really mean AW adds?
 

MolaKule

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Recip engine oils use a high viscosity oil film for the majority of wear protection and to assist compression. Extra AW protection is provided by an ashless AW additive. The dispersant is provided by an ashless succinic dispersant. Then there are corrosion inhibitors and rust inhibitors added to combat any rust or corrosion. Neither Jet Turbine oil nor aviation recip oil is appropriate for terrestrial engines.
 
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MolaKule

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Originally Posted By: Oldmoparguy1
AeroShell 15-50 works great in my B&S lawn tractor. Wayne
Maybe so, but you are using a lot of fuel to churn and heat the oil.
 
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Originally Posted By: MolaKule
Originally Posted By: Oldmoparguy1
AeroShell 15-50 works great in my B&S lawn tractor. Wayne
Maybe so, but you are using a lot of fuel to churn and heat the oil.
I decided to test that this morning, on my Briggs Quantum mower. Have been using 5W20 synthetic through winter (grass hasn't died off at all this year it's been so mild). Mowed this morning, then left it sitting at the Governor for 10 mins or so. Temperature of the oil (thermocouple down dipstick hole) was 87C. Changed oil to 20W60...97C. For explanation, that's the new equilibrium temperature that the oil has to sit at to dissipate the extra work the engine is doing against it.
 

MolaKule

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Those results are similar to tests I ran in Kansas about 2003/4. Engine was a 20HP B&S mounted on a riding mower. I went from a synthetic 0W30 to a 5W30 to 10w30 to a 10W40 to a 15W50 and measured head temperatures at the same spot with the ambient temperature at about 95F, low humidity about 35%. Temp went up about 7-10F for every step increase in oil weight. Using the lowest viscosity oil for the lowest wear is still a good motto.
 
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