Based on the G100UL fuel leak thread what's your position?

[A64Pilot]

The chief reason we change oil at 50 hours, 25 if we have no filter isn’t lead. The cutting the interval in half for no filter is a clue as a filter doesn’t filter lead out.

It’s carbon and other combustion by products, see we have very loose, sloppy cylinder to piston tolerances that result in a very high rate of blow by when compared to most any water cooled engines.

Being air cooled and rather huge bores (V8 displacement with 4 cylinders) and the fact that no matter how badly the pilot abuses it, it isn’t allowed to seize means we have to have sloppy tolerances, that’s why we run such thick oil. 0W-20 would go past our rings at an astonishing rate.

Not saying getting rid of lead isn’t desirable, but I’m not extending oil change intervals, oil is just too important. I don’t fly a lot of hours and change mine every 25 hours myself, if I flew long flights then I’d probably do 50.

Ref Syn oil, there isn’t any. Perhaps maybe there will be after some time but I’d be surprised if there was, the market is so small I don’t think there is real money in it, or Exxon would still be selling Elite.

Besides there is very little actual Synthetic oil anymore since years ago Castrol marketed their mineral oil as Synthetic and got away with it, even Mobil 1 had to sell mineral oil as Syn because they couldn’t compete price wise if they didn’t.

http://xtremerevolution.net/a-defining-moment-for-synthetics-by-katherine-bui-lubricants-world-1999/

I think Amsoil may still be PAO Synthetic, but not sure, but there are very few actual PAO base stock oils out there anymore.

[dzeleski]

52 minutes ago, A64Pilot said:

The chief reason we change oil at 50 hours, 25 if we have no filter isn’t lead. The cutting the interval in half for no filter is a clue as a filter doesn’t filter lead out.

It’s carbon and other combustion by products, see we have very loose, sloppy cylinder to piston tolerances that result in a very high rate of blow by when compared to most any water cooled engines.

Being air cooled and rather huge bores (V8 displacement with 4 cylinders) and the fact that no matter how badly the pilot abuses it, it isn’t allowed to seize means we have to have sloppy tolerances, that’s why we run such thick oil. 0W-20 would go past our rings at an astonishing rate.

Not saying getting rid of lead isn’t desirable, but I’m not extending oil change intervals, oil is just too important. I don’t fly a lot of hours and change mine every 25 hours myself, if I flew long flights then I’d probably do 50.

Ref Syn oil, there isn’t any. Perhaps maybe there will be after some time but I’d be surprised if there was, the market is so small I don’t think there is real money in it, or Exxon would still be selling Elite.

Besides there is very little actual Synthetic oil anymore since years ago Castrol marketed their mineral oil as Synthetic and got away with it, even Mobil 1 had to sell mineral oil as Syn because they couldn’t compete price wise if they didn’t.

http://xtremerevolution.net/a-defining-moment-for-synthetics-by-katherine-bui-lubricants-world-1999/

I think Amsoil may still be PAO Synthetic, but not sure, but there are very few actual PAO base stock oils out there anymore.

https://www.boldmethod.com/blog/2013/11/aircraft-oil-mineral-ashless-dispersant-synthetic/
 

Shell Oil tested all-synthetic oils in aircraft engines, and what they found wasn't good. At 600 to 900 hours, the engines began to burn more oil and lost compression. "When the engines were disassembled, we found that the piston rings were covered with a gray tacky substance that was primarily made up of the lead by-products of combustion."

 

https://generalaviationnews.com/2005/03/11/synthetic-oil-is-it-right-for-your-plane/

Back in the 1960s, Shell ran several flight evaluations of oil formulated with all-PAO base oil. The oil performed very well except in large engines, (turbocharged 520s and 540s). In some of these engines, the oil failed to absorb the lead salts from the combustion process. This resulted in gray sludge buildup in the ring belt and props. Shell then changed to a semi-synthetic containing only 50% synthetic base oil and the rest normal mineral oil to alleviate the problem.

 

There are plenty of synthetic oils but most companies are using blends today. Amsoil, redline, motul are all using group 4 or group 5 oils. Our airplane oils are clogged up with lead by products which is the primary reason we need to replace it so often.

 

 

Edited 5 hours ago by dzeleski

[Echo]

20 hours ago, gabez said:

I think you are missing the point....G100UL is a drop in replacement, it is supposed to behave like 100LL....it doesn't....otherwise our deficient airplanes would have experienced the same problems with 100LL. 

That’s a bingo

[A64Pilot]

I understand that “true” Syn oil, PAO’s won’t put lead into suspension, or at least they won’t in our engines. They do fine in Automobile engines though. I was stationed in Germany from 93 to 96 and every station had leaded fuel then and many ran PAO oils.

Mobil 1 found that out the hard way, it was FAA approved of course, but obviously wasn’t adequately tested. It doesn’t take much mineral oil to prevent the problem, so blends are fine.

What I am saying is that if you remove the lead, yes you can most certainly run PAO but it shouldn’t significantly increase your oil change interval, because we, very much like Diesels don’t change oil because it’s worn out, changing viscosity or the additive packages breaking down, we change oil to get the carbon etc out, carbon as I’m sure you know is very abrasive. Diesels trash their oil with soot, especially newer ones with EGR

Some turbo motors are the exception, some turbo motors if they are run hard (hot) are hard on oil and can cause it to prematurely break down, those possibly could run normal 50 hour change intervals with PAO oil.

All I’m saying is if or when we go to unleaded fuel, it’s unlikely our oil change intervals will change, we aren’t Rotax engines

Edited 4 hours ago by A64Pilot

[MikeOH]

Unless Lycoming changes their recommendations, even if UL fuel would allow 100 hour oil change intervals it is no practical help for most of us.  Per Lycoming SB480F you have to change every 4 months, anyway.  So, unless you fly over 150 hours/year you won't save on oil changes.

 

[Justin Schmidt]

44 minutes ago, MikeOH said:

Unless Lycoming changes their recommendations, even if UL fuel would allow 100 hour oil change intervals it is no practical help for most of us.  Per Lycoming SB480F you have to change every 4 months, anyway.  So, unless you fly over 150 hours/year you won't save on oil changes.

 

 not a requirement in part 91.

[ragedracer1977]

13 hours ago, philiplane said:

For what it's worth, fuels are not tested to be compatible with paint. They're not expected to be routinely applied to painted surfaces. 

that’s true, because there’s only one fuel. However, paint manufacturers absolutely test for resistance to chemicals expected to be encountered.  This applies to automotive paint manufacturers too.

Also, the test videos shown do not specify what paint systems were used on the parts. This is a critical part of testing. 

If you mean GAMIs videos, you’d be correct.  If you mean the other guys, you’d couldn’t be more wrong.  He not only tells you what paint, but when it was painted.  In some cases even shows you the actual lot number the part was painted with. Yes, there are a few panels he doesn’t know, but for the most part he is very specific.

As for rubber components in the fuel storage and distribution system, it seems obvious that more testing is needed to identify and develop solutions to any potential G100UL compatibility issues.

100% yes.

See replies above.