100 LL fuel

[Castorero]

Anyone know what the longevity of 100LL fuel might be?

I have heard a lot of contradicting opinions on this question over the years, but never had to really worry about it as my burn rate was pretty consistent.

The issues is a cache of 1200 gallons of100LL that is at least 10 years old, stored in a remote area in a single tank inside a shed.

Can the fuel be tested in any way and who would do that?

Are there additives to bring it back to life if it has become somewhat flaccid?

I am reluctant to start using this fuel before we shine some light on it...

Any thought?

Castorero

[Heliian]

DO NOT USE THAT FUEL!!

1. it's expired
2. It's probably full of water.
3. there is no test or additives to bring it back.


I'd use it in my old boat motor though. Maybe even an old car.


DEFINITELY DO NOT USE IT IN AN AIRCRAFT.

There's probably not 1200gals anymore just from evaporation. The tank is probably corroded too.

[digits_]

6 year old avgas in a sealed barrel has been ok.

10 year in a tank sounds.... exciting...

[AirFrame]

I have heard a lot of contradicting opinions on this question over the years...

So you thought you'd go to an anonymous internet forum to get the *definitive* answer?

Maybe call Shell or Imperial Oil or someone who makes it?

[Commonwealth]

..[/quote]

Maybe call Shell or Imperial Oil or someone who makes it?
[/quote]

The only thing a fuel manufacturer can say is that the fuel is unsafe and should be disposed of in accordance with local laws.

I believe this is the perfect place to discuss this topic because we can read all opinions.

I have many questions but I’ll only ask one. Does this fuel belong to you?

[Cessna 180]

Sounds good to use in a dirtbike, lawnmower, carbureted motorcycle, once you drain the water and check for tank corrosion. Wouldn't use it in an airplane.

[JAHinYYC]

The Google took about 0.0001 seconds to spit out that 100LL is considered usable for about a year after manufacture (ex Shell scientist)...

https://generalaviationnews.com/2011/05 ... -stored-2/

After ten years stored in uncontrolled conditions do you really want to be the test pilot for this cache, especially when your ability to remain aloft is contingent on the fuel being of sufficient quality to sustain flight and not damage the engine it is used in?

[PilotDAR]

Research the standards to which the Avgas was certified. ASTM D910 & D439 are starting points. You may come to understand that Avgas and Mogas are not at all alike in their formulation, and age differently as a result.

Of course, contamination and water content are vitally important factors for safety. If the fuel is perfectly clean, and water free - and you're very sure about that, your next step is to understand the standards, and how the fuel is formulated. Mogas ages because of how it is forumlated. Mogas such that if it is too old, you probably won't get an engine to start on it, so running on it is not really a risk - it didn't run!

Understand terms including "light ends" and "vapour pressure", how age affects them, and how they're different in Avgas and Mogas, and you're headed in the right direction to form your own informed opinion...

I'm not giving you an answer, nor telling you what you should do (nor what I would do), but hopefully some hints will help you inform yourself...

[photofly]

Don't forget to look at the oxidation of the tetraethyl lead, and the decomposition of the ethylene dibromide lead scavenger

[goingnowherefast]

Sounds good to use in a dirtbike, lawnmower, carbureted motorcycle, once you drain the water and check for tank corrosion. Wouldn't use it in an airplane.

Even then, you'll be changing spark plugs for lead fowling. I ran a generator off avgas for a day before it started misfiring. No modern engines are designed to deal with lead. Maybe some vintage car owners would be able to use it, but that's about all.

[trey kule]

Really? Fuel that has been sitting in a tank in a shed for 10 years.

And there is a discussion regarding using it to put in an aircraft engine...to fly.

Has common sense gone so far south?

Avgas can be tested to see if it is within spec. But that is a complete waste of time after 10 years.

This is one of those discussions where one has to just shake their head in wonder.

To the original poster....”No it is not usable”.

[Castorero]

Thanks for all the replies.

There is much that I dont know about aircraft fuel. I read that 100/130 was indestructible over time, if properly stored. A far cry from the fate of Mogas etc.

This will necessitate some more in depth research to understand the organic chemistry.

I neglected this fuel for some time, but there is no contamination and the tank has never had any condensation and it has had a pressure cap on it.
I would have thought that an R-985 would burn just about anything you fed it...

Stay tuned, I will look into this in some depth and report back in due course.

From some accounts this may turn out into a fool's errand. I am keeping a slightly open mind....

Castorero

[RedAndWhiteBaron]

I don't use gas older than 2 years in my boat, a little 7.5hp two-stroke, and even then, that's with a fuel stabilizer to get it to last over the winter. Even after one winter, I can tell within two or three pulls of the crank that I'm running old gas, before the engine has even turned over. It's dirtier after a winter too, visibly, in the exhaust and by the fouling on the spark plugs. And this is regular 87 octane mogas.

And if my boat's engine stops, I'm just stuck rowing. Airplanes sort of have a different risk profile.

So, no, I'll repeat the refrain here. DO NOT USE THAT FUEL.

Now, on the other hand, I've always wanted to build a massive trebuchet, and launch 40 gallon drums of gasoline kitted out like giant molotov cocktails with it. This fuel would be perfect for that, at least.

[Castorero]

How time flies...

This Summer Season is almost over and so is the 1200 Gls of 100LL that has been sitting idle for at least 10 years.
I didn' t have too many qualms about burning this "old" fuel in a R-985 that was certified to function in the days of 80/87 octane.

The fuel was well stored in a closed fuel shed in a tank with a slight rearward tilt for drainage and a pressure cap on top.
The fuel passed the sniff test with flying colors and the empty rear tank was filled for a test flight.

As expected,when a good safe altitude was reached over the lake, the rear tank was selected and, well nothing unusual happened. Over the next week the other two tanks were filled sequentially with the old fuel and the rest is almost history.

As expected, talking to the experts, and engineers at two refineries yielded the usual legal caveats, which is understandable.

Not being a chemist, what I took away from this experience is that 100LL, being a clean fuel, what remained in the tank after 10 years was pretty much the same as it was, and being free of the usual contaminants like rust, water and dead mice, performed as expected in the R-985.
This is pretty much also what I got from talking to pilots that have been around since that engine was certified.

This was a seat of the pants experiment and I don't recommend it to anyone.

I should add that Mogas is a beast of a different color that deteriorates very differently than 100LL and definitely should not be used in any airplane engine after 3 months, in my opinion.
Given the variable quality control of Mogas, I would not use it in any airplane that my life depended on.

[digits_]

Hehe. I like your style...

Thanks for reporting back, and happy that you still could do so!

[Choppermech1986]

I read your question and though, "It'd probably be fine", and thinking to myself that I must be an absolute cowboy after reading all the replies you got.

Glad to know that I'm not so silly. Mogas is indeed different, with ethanol in it, it's madness to put it through a certified normally aspirated engine at anything less than 1:4 in a pinch and even then, it's to be run out of the aircraft ASAP.

Good on you for making a judgement call and using some common sense and then getting back to us with your results.

[PilotDAR]

Fuel caution and awareness is great, and if in doubt, don't. Assure that the fuel you plan to burn is free of water and contamination. And use a fuel approved for your engine and airframe.

100LL is much more aging resistant than Mogas, so understanding, and caution is great. Fuel manufacturers will of course, promote caution. My experience has been that there is some comfort zone on the edge of manufacturer's recommended practices. For many years, I bought my Mogas once a year or so (that's the rate I used the tankful I bought), and never had a problem with aging. It was used in an STC approved airframe and engine. I did check it for Ethanol at each purchase (and it was always ethanol free, as I requested it). The ethanol is not approved in the airframe fuel system - it can attack non metallic fuel system components.

That said, an airplane fuel system intended for the use of ethanol works fine, when operated correctly. I have about 30 hours flying experience in a 100% ethanol powered Cessna 150, powered by an O-200. It worked perfectly fine, and we never had a problem for the whole test program. If ethanol were a viable fuel to obtain for recreational aviation use, I would have no problem running it. We just found that we really couldn't go anywhere in the plane, as you'd have to buy gasoline to fly home, and that complicated things. It worked, but was complicated, so not worth the effort - but it works. Ethanol in Mogas is fine in an aircraft engine slightly modified to accept it, and similarly in a modified airplane fuel system (compatible non metallic materials) - the planes just aren't modified as needed, it's not that it doesn't work well....