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 January 15 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 January 16 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.

[MikeOH]

1 hour ago, Justin Schmidt said:

 not a requirement in part 91.

Which is why I used the words "Lycoming's recommendation". Wait a year or 100 hours to change your oil; I don't care. Just pointing out Lycoming recommends otherwise.

[PT20J]

2 hours ago, Justin Schmidt said:

 not a requirement in part 91.

Under part 91, there is no requirement to change oil ever.

[philiplane]

11 hours ago, ragedracer1977 said:

See replies above.

To be clear, GAMI is not a paint manufacturer. There is no practical way for them to test their fuel with every paint.

A paint system includes the aluminum surface prep, the primer, any sealers, and the top coat. Listing only the top coat doesn't give enough information. Nor does he indicate the mil thickness of the paint, which is a critical item. You can apply Jet Glo, one of best aerospace paints, on top of cheap undercoats. It will fail easily when exposed to solvents, where it will not fail when a complete, compatible system is applied.

I've been painting custom autos, heavy trucks, and airplanes for over 40 years. Dozens of my antique truck restorations are in museums. While the A&P's video is pretty thorough, it lacks the specifics that would tell us if the damaged panels were correctly painted in the first place. From my perspective, they were not.

[redbaron1982]

25 minutes ago, philiplane said:

To be clear, GAMI is not a paint manufacturer. There is no practical way for them to test their fuel with every paint.

A paint system includes the aluminum surface prep, the primer, any sealers, and the top coat. Listing only the top coat doesn't give enough information. Nor does he indicate the mil thickness of the paint, which is a critical item. You can apply Jet Glo, one of best aerospace paints, on top of cheap undercoats. It will fail easily when exposed to solvents, where it will not fail when a complete, compatible system is applied.

I've been painting custom autos, heavy trucks, and airplanes for over 40 years. Dozens of my antique truck restorations are in museums. While the A&P's video is pretty thorough, it lacks the specifics that would tell us if the damaged panels were correctly painted in the first place. From my perspective, they were not.

I get what you're saying, but from a practical point of view, does it matter much?

I see this because we have something that works well (100LL) with our current fleet. It doesn't matter if the paint is not in perfect shape or if the paint job was not correctly done, 100LL seems to have no significant effect on it. The same applies to sealants, bladders, o-rings, EZ Turn, etc. It could be that all these things are worn out, or they are not the best, or they were not applied as they were supposed. But at the end of the day, what matters is that the fleet is safely flying using 100LL.

If changing 100LL for G100UL makes 10% of the fleet have issues with paint, seals, bladders, etc. I don't care if the main culprit is a job poor done, what I care is that G100UL is the variable that changed.

I'm not saying we shouldn't move to G100UL (given that it is safe), but I think GAMI has to be transparent stating it is not a drop-in replacement. Maybe something like: "Hey, if your airplane is new and everything has been done according to best practices, your are safe, G100UL will not affect you. But, if your airplane is old, your sealants are not in the best shape or you have a poorly done paint job, G100UL could have these effects: fuel leaks, paint peel off, etc."

[A64Pilot]

36 minutes ago, philiplane said:

To be clear, GAMI is not a paint manufacturer. There is no practical way for them to test their fuel with every paint.

A paint system includes the aluminum surface prep, the primer, any sealers, and the top coat. Listing only the top coat doesn't give enough information. Nor does he indicate the mil thickness of the paint, which is a critical item. You can apply Jet Glo, one of best aerospace paints, on top of cheap undercoats. It will fail easily when exposed to solvents, where it will not fail when a complete, compatible system is applied.

I've been painting custom autos, heavy trucks, and airplanes for over 40 years. Dozens of my antique truck restorations are in museums. While the A&P's video is pretty thorough, it lacks the specifics that would tell us if the damaged panels were correctly painted in the first place. From my perspective, they were not.

I don’t think it matters actually if it was correctly painted or not, depending on how you define correct I bet most of our aircraft aren’t correctly painted. From my experience many Aircraft paint shops aren’t real professionals, from what I have seen most Auto paint shops especially those that do a lot of classic cars, show cars etc are much better.

What matters in my opinion is that it went I assume years with 100 LL without damage, but the Gami fuel damaged it.

Plus this damage didn’t occur slowly over months or years, it happened pretty quickly.

If it takes correct tank sealing or correct paint to not be damaged I bet a lot of us are in trouble.

My fuel cells are apparently made from Nitrile, now we know what the effects of the Gami fuel is on Nitrile O-rings, it’s logical to assume that fuel cells made from the same material are at risk.

But here is what concerns me, it’s the fact that some problems have been reported very quickly after this fuel was put into use, I would have expected it to take months at least.

I need to get off my Butt and take a pic of the top of the wing of my C-140 that burns Auto fuel, the C-140’s fuel vent is two holes in the fuel cap, so fuel is siphoned out in flight if the tank is full. I have brown / yellowish fuel stains on my Jet-Glo painted wing, but even if I leave it there for months it polishes off telling me it’s not dissolving / eating into the paint.

But it’s my understanding that the Gami fuel stains don’t polish out, telling me that it’s dissolving / eating into the paint.

If it “eats” Jet-Glo that’s troubling, because that stuff is nearly impervious to a lot of pretty aggressive chemicals.

Edited January 16 by A64Pilot

[Marc_B]

52 minutes ago, philiplane said:

While the A&P's video is pretty thorough, it lacks the specifics that would tell us if the damaged panels were correctly painted in the first place. From my perspective, they were not.

In those videos 100LL did not cause the issues that G100UL apparently did. But you’re right, between Luvara’s videos and Braly’s videos, the end user still has no better idea of what the underlying cause or the specific aircraft at risk are.

GAMI is in best position to help determine the cause, but possible financial disincentive.

GAMI points to pictures of bad leaking on a wet wing and says this is the issue (“hard data”), but we didn’t see the extensive paint damage with 100LL. So I’m just left with the impression “it’s not me, it’s you.”  Not a good advertising technique for my business.

More importantly, how am I supposed to know if I can safely use G100UL in my aircraft?  Until the root cause is known and identified, I can’t.

This is the issue that Mr. Braly points the finger as the cause…and the picture he uses to highlight as “proof” that 100LL is equally as damaging…https://www.aviationconsumer.com/maintenance/fuel-tank-reseal-thankless-expensive/

 

[IvanP]

12 minutes ago, Marc_B said:

More importantly, how am I supposed to know if I can safely use G100UL in my aircraft?  Until the root cause is known and identified, I can’t. 

Absolutely agree with your conclusion. Unfortunately, we may soon be faced with the scenario that this will become the only fuel available by govt mandate. 

Edited January 16 by IvanP

[gabez]

I want to bring everyone back to there are 2 STC, one for the engine and one for the airframe. And, from the GAMI website is a "drop in" fuel. G100UL was sold, commercialized and marketed as drop in fuel.

There is no escape from this, the damage is done. Now it's only matter to quantify how much and if it is with GAMI, VITOL or both. 

is that simple. 

Edited January 16 by gabez

[philiplane]

41 minutes ago, A64Pilot said:

I don’t think it matters actually if it was correctly painted or not, depending on how you define correct I bet most of our aircraft aren’t correctly painted. From my experience many Aircraft paint shops aren’t real professionals, from what I have seen most Auto paint shops especially those that do a lot of classic cars, show cars etc are much better.

 

If it “eats” Jet-Glo that’s troubling, because that stuff is nearly impervious to a lot of pretty aggressive chemicals.

Of course it matters how it was painted. Each paint calls for specific mil thickness when dry. Not too thick, and not too thin. Thick paint ages faster since it absorbs more heat rather than passing it to the structure. Thin paint has poor chemical and solvent resistance, and poor abrasion resistance. It tends to peel easily.

You're misunderstanding the damage. It's not "eating" the Jet Glo. It's dissolving the primer underneath it. And then the top coat shrivels up and peels away. Even concrete will crumble if you wash away the soil underneath it.

The majority of paint jobs have poor surface prep and they use cheap primers to save money. The nice paint on top looks great until a scratch, a nick, or edge wear on access panels gives a solvent a chance to contact those cheap materials underneath. Some shops even use generic hardeners instead of the correct (expensive) ones, and the paint never fully cures.

[MikeOH]

14 minutes ago, philiplane said:

Of course it matters how it was painted. Each paint calls for specific mil thickness when dry. Not too thick, and not too thin. Thick paint ages faster since it absorbs more heat rather than passing it to the structure. Thin paint has poor chemical and solvent resistance, and poor abrasion resistance. It tends to peel easily.

You're misunderstanding the damage. It's not "eating" the Jet Glo. It's dissolving the primer underneath it. And then the top coat shrivels up and peels away. Even concrete will crumble if you wash away the soil underneath it.

The majority of paint jobs have poor surface prep and they use cheap primers to save money. The nice paint on top looks great until a scratch, a nick, or edge wear on access panels gives a solvent a chance to contact those cheap materials underneath. Some shops even use generic hardeners instead of the correct (expensive) ones, and the paint never fully cures.

While I appreciate your expertise in this area the FACT remains that 100LL does NOT cause any problems with paint, regardless of quality and application.  It is beginning to seem G100UL does.

[Kelpro999]

25 minutes ago, philiplane said:

You're misunderstanding the damage. It's not "eating" the Jet Glo. It's dissolving the primer underneath it. And then the top coat shrivels up and peels away. Even concrete will crumble if you wash away the soil underneath it.

 If you look at the way all the failures appear you’ll notice the top coat has expanded to the point of being way too large to lay flat. This has nothing to do with underlay although the substrate is responding same.

[philiplane]

GAMI has this on their site:

[MikeOH]

24 minutes ago, philiplane said:

GAMI has this on their site:

Yes, this has been posted, and discussed, multiple times. The problem is that GAMI's test is NOT the same as the ones Mr. Lavara performed (YouTube) which many of us feel better represents real work condition.  Specifically, he allows the fuel to evaporate (like would happen with a spill or slow weep/seep) and then reapplies G100UL and 100LL rather than constant submersion of the GAMI test.  He has posted two videos.  Both very well done, IMHO. You should watch them.

[Kelpro999]

22 minutes ago, philiplane said:

GAMI has this on their site:

 This does look ok when all compounds are ready to use state, however the reality is all aircraft have fuel cells subject too evaporation and absorption that are continuously changing concentrations of elements.

[Marc_B]

50 minutes ago, Kelpro999 said:

 If you look at the way all the failures appear you’ll notice the top coat has expanded to the point of being way too large to lay flat. This has nothing to do with underlay although the substrate is responding same.

Agreed.  If you look at the Aeronca Champ with paint damage, the paint is bubbled up, not just peeling or flaking off.  Same as the Mooney described in this thread, the Cessna 421C, as well as how it looks on the AOPA Baron.  If it was just attacking the primer you'd think it would just chip and peel rather than bubble and expand.

Is Beechcraft paint technique materially different than other manufacturers?  What coating/primer/paint/etc have they typically used?

[ragedracer1977]

39 minutes ago, philiplane said:

GAMI has this on their site:

You don't see the problem with this methodology?  Even setting aside the fact that the test was done differently...  They have stated again and again that they've tested it against Beech louvre panels, and seemingly ONLY Beech louvre panels.  I'd hazard a guess that testing a likely homogenous cohort has less fleetwide applicability than testing multiple panels from multiple planes, painted with multiple systems.

If this is indicative of their testing methodology in other areas, it's concerning.  And, to be frank, I'm a little concerned that it may be.  See the photo below.  One single oil analysis of one single engine does not demonstrate anything.  

[MikeOH]

15 minutes ago, ragedracer1977 said:

You don't see the problem with this methodology?  Even setting aside the fact that the test was done differently...  They have stated again and again that they've tested it against Beech louvre panels, and seemingly ONLY Beech louvre panels.  I'd hazard a guess that testing a likely homogenous cohort has less fleetwide applicability than testing multiple panels from multiple planes, painted with multiple systems.

If this is indicative of their testing methodology in other areas, it's concerning.  And, to be frank, I'm a little concerned that it may be.  See the photo below.  One single oil analysis of one single engine does not demonstrate anything.  

Agreed.  Not to mention what is to say the difference in wear metals is due to some difference between the condition of the left vs. right engine?  What would the chart look like if you swapped fuels for the two engines?

[philiplane]

34 minutes ago, Marc_B said:

Agreed.  If you look at the Aeronca Champ with paint damage, the paint is bubbled up, not just peeling or flaking off.  Same as the Mooney described in this thread, the Cessna 421C, as well as how it looks on the AOPA Baron.  If it was just attacking the primer you'd think it would just chip and peel rather than bubble and expand.

Is Beechcraft paint technique materially different than other manufacturers?  What coating/primer/paint/etc have they typically used?

Beech, Piper, and Cessna use virtually identical paint systems. Cirrus does too. But in the aftermarket, anything goes and quality is anything but uniform. As I mentioned, it is more common than not, to find shops using a mix-match of materials in an effort to contain costs. Very few use the OEM procedures and materials. I've only seen one paint shop measure mil thickness of each step, and on the final finish coat on a light aircraft. That was a jet shop in Oklahoma, who did it in the same manner as their jet work. Many shops will use primers that will do exactly what you've seen in the photos when exposed to xylene or toluene. Again, the top coat is a victim of primer failure, not the other way around.