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Synthetic Oil

My guess is: "No".
Recommend a visit to Lyc's website and see what they recommend.
Try searching this forum, as well.
 
Many of today's aviation oils are semi-synthetic, which means a blend of synthetics and mineral oils. When pure synthetics were tried (Mobile, if I recall correctly), they ended up with some serious problems because the synthetic oil couldn't suspend the lead combustion byproducts, and all the lead ended up as sludge in the crankcase. That, in turn, led to Mobile paying to rebuild quite a few engines.

So, none of the commercial sources sell pure synthetics for aviation. However, if you were running unleaded fuel, a synthetic might work. Or might not... ;-)
 
sure do!

I run Amsoil 20W-50 at about 25% in my TCM 550. I know of past problems with lead deposits & sludge, but I'm not running the stuff at 100% in this engine. I'm expecting the Phillips X-CY (@ 75%) to scavenge the lead. I'm expecting the Amsoil to reduce or eliminate internal rust in this application.

I did run this Amsoil straight (100% synth) in a 540 -- no oil changes in about 140 hrs after puttiing the stuff in. Dropped it at a mech's place for HP upgrade (cyls/pistons/cold air) -- he called when he opened 'er up and asked me how many hrs were on it and what oil did I use. He related that the inside looked new, and very clean. The engine had about 500 hrs on it then, and as I mentioned the oil had 140 hrs on it. I did change filters every 50 hrs....

Amsoil is an ashless dispersant oil, so I wouldn't expect any problems if you did decide to run it straight.

You can get on their distributor program, and get the stuff for far less than full retail. The extended change interval available with this type of oil is a good thing -- be sure to figure that into your cost equation.

Carry on!
Mark
 
high hours on oil

I have no particular view on Amsoil, but the idea of running 140 hours on one oil change seems not very wise. It is not an issue of the oil "wearing out". It is an issue of chemical pollution. Filters remove gross particles in the multiple micron size range. Some say that our clearances are so loose that the smaller particles are thus OK. None of this, however, deals with the issue of the pollution of the oil by by-products of combustion and the consequent formation of, for example, acids. Even the elimination of water vapor from the engine during non-running periods can't prevent that. Water vapor is a result of burning gasoline. It gets into the crankcase by getting past the rings; then it gets into the oil. And, of course, some the oil is burnt and the burnt stuff lodges in the oil, too.

Would any of you who do run long oil-change intervals like to help me understand this from your perspective?
 
Does anyone use synthetic oil in there Lyc's successfully?

Pat

After the Mobil 1 aviation oil lawsuit, I will not even try a full synthetic aviation oil but have no problem running the semi-synthetic aviation oils that are approved for aircraft engines.

Info on the lawsuit and Mobil 1 Aviation oil can be found at the following two links.

http://www.avweb.com/news/news/182891-1.html

http://www.avweb.com/news/news/182892-1.html

I will not use any oil that is not approved for the engine and fuel that I am using regardless of the application that I use the engine in.

BTW. I use a manufacturer recommended Rotella synthetic diesel oil in my diesel car. It is recommended to be changed every 10,000 miles. I forgot at the last change and went 14,000 before change. It was down one quart when I changed and I did not add any between change.

I like synthetic oil, I do not exceed manufacturer recommend change intervals on purpose, I do not have a issue with paying a little more, and I have a BIG issue with paying a LOT more for it.
 
A friend of mine bought every bit of Mobil 1 synthetic aircraft oil he could find when they discontinued it, and continued running it in his Aerostar for hundreds of hours with no problems. Still has cases of it in his hangar. He ended up trading the Aerostar for a Cheyenne 400LS, otherwise the oil would be used up by now.
 
You have to ask yourself, what actual advantage do you hope to gain with the more expensive synthetic (at the risk of it not performing as well) when oil changes should be done at 50 hour intervals anyway?

Friends don't let friends use synthetic for aviation. At least, not in Lycs burning 100LL. Maybe in a Subie burning Premium.
 
Shell 100W Plus is the only way to fly... 15W50 Syn does absolutely nothing for you... well, I take that back, it will take more money out of your wallet!!
 
What semi-syn does for you

Shell 100W Plus is the only way to fly... 15W50 Syn does absolutely nothing for you... well, I take that back, it will take more money out of your wallet!!
  1. Don't have to worry about spring and fall when the WX here in MI keeps changing from one "bracket" to the other. Multi-viscosity solves it.
  2. The mfr (Superior) recommends it.
  3. It is proven to retard rust better.
  4. The former head of oil research at Phillips said it (Elite) was better/best in a presentation at OSH a few years ago.
  5. Since synthetics have superior lubrication properties, you get some improvement over non-synthetic.
  6. When starting in temps at the bottom of the acceptable range for the viscosity you are using, the straight-weight oil does not flow as well at first and thus is lubricating less at a critical time.
 
Shell 100W Plus is the only way to fly... 15W50 Syn does absolutely nothing for you... well, I take that back, it will take more money out of your wallet!!

The only problem with 100% synthetic oil in aircraft engines running 100LL is it does not suspend the lead. This is why Shell has 50/50 oil. The synthetic component provides vastly superior engine protection and better flow in cold temps, and the dino componet suspends the lead. The theory is you get the best of both worlds.
 
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I like the idea of full synthetic, and we do run Redline 50w (actually 15/50 I believe) in our little O-200 race motor with no ill effects. However, since that oil gets changed every hour or two, and it's application is severely different than day-to-day use of a RV, I don't think I'd run it.

Here in socal, Aeroshell 100w (NOT plus) in everything, it's cheap, and NEVER had a problem with it. In colder climates, Phillips 20w50 (Non syn, non Lyc additive). If you have an H2AD, I buy the Lyc additive seperately and add it myself.

Why do I? Because it just works, why mess with something that just works?
 
Geez....

So have any of you fellas switched to AMSOIL yet? In case you don't know, it is an ashless/dispersent oil - same as all other aviation oil. So yes - it does keep the lead in suspension.

As for costing you more, remember the change interval is at least 2 what std oils recommend, and yes I did run out to a 140hr change to see if anything happened. NADA, and the re-builder wanted to know why the case/cam/rods/under side of the pistons etc were so clean when he opened 'er up.

AMSOIL break-in oil has a big dose of zinc - better to help the cam and other sliding surfaces break in with no problems. Our aircraft engines needs zinc anyway - it's not like a modern auto engine that has all that stuff in the exhaust pathway that gets plugged up by a big dose of zinc...

Again - you don't need the full oil change to be AMSOIL - about 25% will do it. I would use regular intervals if mixed that way.
 
An Independent Test

A million years ago when I was an engineer at Kennedy Space Center, I had contacts in the labs there. These were young co-workers/fellow pilots/hot rodders that liked to get their hands on new products, test their claims, etc. Ex. they did a test on the "new" preservative oils/treatments of the day; ACF-50, Boeshield, LPS, later CorrosionX.

They tested some full syn oil versus AD and multi-weights (there was another "revolutionary" car oil additive at the time included. Edit = Slick 50). The full synthetic was superior in all of the property/characteristic tests they performed (lead scavenging/suspension not included). On paper (ASTM, ASME, API standards) it was fantastic. A big surprise to the lab guys; the more synthetic in the blend, the less affinity the oil had for metal surfaces (their words). The oil film didn't remain on the test surfaces very long compared to the dino blends. It led to lots of discussions of a needing a pre-oiler, only using in OH valve engines unless it was a daily driver, etc. Think of starting something with an OH cam days/weeks after it's last run. My mind was made up there to never use it in an aircraft. Though I'm sure there's been improvements in the properties since then, that prejudice has remained.

If anyone has real evidence (not anecdotal) if this property has been improved, could you please share? This woke up some ancient memories. Much appreciated.
 
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So have any of you fellas switched to AMSOIL yet? In case you don't know, it is an ashless/dispersent oil - same as all other aviation oil. So yes - it does keep the lead in suspension.

As for costing you more, remember the change interval is at least 2 what std oils recommend, and yes I did run out to a 140hr change to see if anything happened. NADA, and the re-builder wanted to know why the case/cam/rods/under side of the pistons etc were so clean when he opened 'er up.

AMSOIL break-in oil has a big dose of zinc - better to help the cam and other sliding surfaces break in with no problems. Our aircraft engines needs zinc anyway - it's not like a modern auto engine that has all that stuff in the exhaust pathway that gets plugged up by a big dose of zinc...

Again - you don't need the full oil change to be AMSOIL - about 25% will do it. I would use regular intervals if mixed that way.

After my experience with AMSOIL in my racecar years ago I wouldn't recommend it to anyone. We had been running Mobile then switched to AMSOIL and blew two or three engines within a year. After that we switched to Brad Penn and never had another issue. AMSOIL is also ridiculously expensive, even if you get the distributor price. Granted our engines were turning 16,000rpm, but still...
 
Rotella

I've also been hearing of people running Shell Rotella T. Anyone out there doing this?
 
Sure have

I know I did a test on that oil too - no problems - but I recall that one might have a particular smell when pulling to idle when landing. I do not know if that oil is ashless...
 
Does anyone use synthetic oil in there Lyc's successfully?

Pat
You mean, like, Mobil 1? And when you say "successfully", do you mean "no serious engine damage " or "no catastrophic engine failure"?

I can't think of any reason I'd elect to use any oil in my engine other than what Lycoming recommends. I recognize that this is "experimental" aviation, I applaud the ingenuity of many of you guys, but my engine is not something that I'd be willing to "experiment" with.
 
So have any of you fellas switched to AMSOIL yet? In case you don't know, it is an ashless/dispersent oil - same as all other aviation oil. So yes - it does keep the lead in suspension.

As for costing you more, remember the change interval is at least 2 what std oils recommend, and yes I did run out to a 140hr change to see if anything happened. NADA, and the re-builder wanted to know why the case/cam/rods/under side of the pistons etc were so clean when he opened 'er up.

AMSOIL break-in oil has a big dose of zinc - better to help the cam and other sliding surfaces break in with no problems. Our aircraft engines needs zinc anyway - it's not like a modern auto engine that has all that stuff in the exhaust pathway that gets plugged up by a big dose of zinc...

Again - you don't need the full oil change to be AMSOIL - about 25% will do it. I would use regular intervals if mixed that way.

AMSOIL is not an ashless dispersant oil. I know many people with certified, as well as experimental aircraft, that have used it over many years without any issues at all. Even though it is not designed to handle lead deposits, it some how does it. Keep in mind that since it is designed for ground vehicles there is no warranty offered for any aircraft use. george
 
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