Av gas & reg gas

I would think the vapor pressure differences would be a real concern with automotive fuel in aviation use!
 
There is no water content in gasolin3. It all settles to the bottom of the tank. That is why every preflight includes draining the sump of each tank into a clear glass container and checking for water.
 
I totally agree with your comments. Here in NJ we have had 10 % for years. I use it all my old cars for over 20 years or when ever it came out.. Never had a fuel related problem - pumps, carbs, etc. The gas in put in October/November is the same that starts the car in April with no problem. no junk like sta-bil either. My son used sta-bil one year and it totally gummed up his carb


keith oh said:
I think this "Alcohol gas problem" is way over stated. I have used the 10% Alcohol gas since it came out with no problems in my Flathead V8, Cessna 85, 100, 145, Lycoming 150 Hp, numerous tractors, lawn mowers, chain saws and smaller engines with no problems. My only problem was when lead was removed I was suckered into using some of the "Insted of Lead " product that a while jelled up in the float chamber carbs. I have many times allowed alcohol gas to remain for over a year and had no problem. Beats me why I am so lucky.
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As far as I'm concerned, it is overkill. Never used it and never had a problem with 10 % in cars that sat over the winter.


34fordy said:
Would that indicate products such as Sta-Bil might be overkill and no longer necessary over winter storage?
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I have and continue to use 10% ethanol in all my small engines and modern cars.

I do use an emzine-based additive to neutralize the alcohol in my flathead gas just to protect the steel tank from corrosion. The rest of the fuel system in it has been rebuilt to avoid ethanol problems.
 
Guess it just depends on your experiences with the stuff. I have seen a lot of damage from the ethanol, it eats up aluminum, rubber, steel, etc. If you can get by using it, guess that is a good thing, but not my experience. Non-ethanol gas is easy to come by where I live so problem solved (for me).
 
I agree with JSeery. The few extra bucks each year for me is not worth the chance. I use non-ethanol in everything I have that has a carb.
 
For years folks would purchase a pint of an alcohol product to absorb the condensate water that forms in the fuel tank over the summer months and tends to freeze up during the winter causing problems. This was long before they actually started adding it to fuel. Now that they add it in there on a regular basis, it shows up another problem with alcohol. When it absorbs water, it will get saturated and fall to the bottom of the tank where is starts growing fungus and picking up other trace materials in the fuel that can come from long term storage. The volatile compounds in fuel tend to evaporate and leaves the chemical structure changed as further oxidation occurs. The mix of all this is what corrodes metals & deteriorates rubber compounds and it takes a while for it to clear the system since most fuel tanks have a bit of a stand pipe in the bottom. Most tanks are vented and fuel likes to be sealed up away from air to keep it from oxidation.


A similar thing can happen in the float bowl of the carburetor or in fuel pumps if the vehicle sets for long periods. This can be reduced a lot by daily use of the vehicle and a constant renewal of fuel in the tank but this isn't always practical. Draining the tank and fuel system is not all that practical either unless the car is going to set for extended periods but I doubt if it's common for folks to do this. Sea Foam, Sta-Bil, and other fuel stabilizer additives might slow the oxidation process some but it won't completely stop it or evaporation. Your engine has to burn that stuff too right along with everything else.


Colder times of the year generally have less condensation unless the vehicle is subjected to more extreme changes in temperature from cold to warm & warm to cold. Evaporation is slower in colder months so that can be a good thing for fuel. Humidity drops a lot during the cold months so that helps too. When I worked in the Rockies, we would get a rapid warm up coming up from Arizona at times during the winter months. We would be having vapor lock problems with the fuel trucks till a cold front would come through again. The winter fuel with it's higher volatility would vapor lock easily if it gets too warm.
 
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Agree Rotorwrench ethanol in fuel is detrimental to small engines and old engines anything carburated. We need to explore for more oil (it's here) and bury more politicians.
 
34fordy said:
Is aviation gas less prone to becoming stale? Or is that an old wives tale?
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This is Mike Jr... posting on dad's old account. I get on here every few months to keep up on old messages, etc... look through his old messages for info on his old cars I still have, and sometimes browse though the forums.

Anyway, as was said, gasoline has a certain average volatility... which is how easily it evaporates. Gasoline is also a mixture. It's a mixture of lights and heavies... components that evaporate easily, and not so easily. Auto fuel has a fairly wide range... especially nowadays, since the higher pressure EFI fuel systems (in tank pump) of today's cars are not prone to vapor lock. This allows their fuel to have a wide range of lights and heavies, and still maintain the correct 'average'.

Aviation fuel does NOT have this luxury. It cannot have as many 'lights' as automotive fuel, as vapor lock is a HUGE issue in an airplane. Vapor lock is further aggravated by the lower air pressure of altitude. To have the proper AVERAGE volatility, it has to have a tighter blend of components... fewer lights, fewer heavies, and more in the middle.

Gasoline goes stale by the lights evaporating off. Since Av-Gas has fewer 'lights', or easily evaporating components, it has a longer shelf life, and does not go stale as easily as automotive fuel. Its longer shelf life, along with the fact that it has no ethanol, makes it PERFECT for small engines, and applications like our cars, that are only operated infrequently, and are stored for periods of time. Sure, these items do not need the extra octane, and if you have non-ethanol fuel nearby, that's fine... but, Av-Gas is the best... as it has an incredible shelf life, as well as no ethanol.

Fuel goes 'stale' by the lights evaporating out... so to maximize shelf life, store the vehicle in a cool place. Store it with a full tank, so the lights have less head/air space above the fuel to evaporate into... and if you're storing the fuel in containers, store them in SEALED units, filled to the top if possible, so the lights cannot evaporate out. Out of the sunlight is also good.

Good Luck
 
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keith oh said:
I think this "Alcohol gas problem" is way over stated. I have used the 10% Alcohol gas since it came out with no problems in my Flathead V8, Cessna 85, 100, 145, Lycoming 150 Hp, numerous tractors, lawn mowers, chain saws and smaller engines with no problems. My only problem was when lead was removed I was suckered into using some of the "Insted of Lead " product that a while jelled up in the float chamber carbs. I have many times allowed alcohol gas to remain for over a year and had no problem. Beats me why I am so lucky.
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Consider yourself lucky. 10% ethanol blend has destroyed the carburetors in 4 of our Stihl chainsaws/leaf blowers/string trimmers. It's caused us significant headaches in all carbureted 4 cycle engines also.
 
I do consider myself lucky,Seth, having survived for 86 years eating, drinking and breathing all kinds of BAD foods, liquids and air warned about by EPA, OSHA and well meaning organization plus others. I will keep on and maybe my vehicles and I lill make it another couple of years.
 
An old time marine mechanic told me he has been using AV gas in all his small equipment including 2cyl outboards He say he can leave it in the tank and carb with no ill effects like you would get from gas with alcohol in it. Another friend said he ran 30% 102 octane AV gas and 70% regular gas in his vintage midget and said the car ran better and he had much quicker lap times. Thank you for all your thoughts. We live in Massachusetts, and there no such thing as alcohol free gas here. I used to run Amoco Ultimate, that all went away.
 
I tied in an outboard once and I could not get the damn thing to fire. Think the fuel was just to lazy.
 
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Funny we put 10% Eth in our now $40-50g trucks. They run fine. But they are made for it... I guess. Norm is to buy a new vehicle every 10 yrs sooo... Maybe that's all they are made for.



Here there is non-eth available. called Non-Oxygenated. I'll continue to buy this for boat motors, lawn mowers. trimmers, and my fords that may sit for long periods. No issues.



If you are going to burn a tank on a trip in a few days, eth isn't going to do "huge" damage if anything in my experience.


I'm waiting on my nuclear powered lawn mower as promised in the 50's :).
 
Seth Swoboda said:
Agree Rotorwrench ethanol in fuel is detrimental to small engines and old engines anything carburated. We need to explore for more oil (it's here) and bury more politicians.
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I'm a naturalist, so I'm with ya but... All that LP they tapped in the bush yrs on public land, will be going to the EU now. We will see very little.


That land was setup as a national treasure for everyone in American. Sure it's complicated. But it's really like a savings account or a place we can just enjoy.


Kinda wish we could make solar and electric cars work, then there would be more gas available. or not... my 2 cents.
 
Talkwrench said:
If you're using it for that equipment and most certainly at 100% it wont work.
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And that statement is 100% wrong!
The only difference in small equipment is, over a long period of time it may, but not likely, lead foul the spark plug.
As noted before, the old av gas, before 100LL, would store for a LONG time without going bad, even for racing. The 100LL of today WILL store and stay good longer than regular street gas if corked up and kept cool.
I have been running av gas for racing since the early 50's. In vintage racing of today, it is still a bargain over "race gas". In any automotive engine, you need to know how to tune for it though. It will generally need 4 to 5 degrees more advance on the timing and slightly richer on the mixture. The plugs will appear gray from the lead so don't let that send you astray. Read the center electrode only.
At the end of racing season, I have always run what is left in the barrel out in my chain saws , weed trimmers and parts chaser.
 
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