how long can you let av gas sit?

[70shortwide]

Ive come across a deal on some av gas, about 40 gallons. its ll av100. im thinking of running it in the truck this summer. only thing that has me a little leary is that hes had it "for a year or so". how long will it sit before it breaks down or goes bad? he says its been in a sealed drum.

[scott123]

If its in a sealed container , a long time. Evaporation kills fuel.\

as for running it in your truck, unless it is high compression and really built ( I mean really built) you will prob ruin your engine.

[Salt-shaker]

Good afternoon 70shortwide, It been sometime for me on the aviation fuel issue but here is my input..Av gas normally came in a rich- lean rating such as 80-87 octane ( RED Colored) common or less common 100-130 ( BLUE Colored )..There were five grades as I remember from 80 to 145 octane. I remember this fuel as having a formula make-up for use in air cooled engines exception being some WW2 fighters ( P51 etc). I run racing fuel in a gas powered race car and it has the appearance ( PURPLE ) and aroma of av gas but I believe the chemical make-up is different. I store 55 gallon drums for long periods ( one year and greater ) without a problem if properly resealed kept moisture free and in a cool spot.. I don't see a real advantage to getting some aviation 80-87 when you can go to the local service station pump for this and you can avoid the danger and possible canceled Fire insurance policy if something bad occurs. I know it hard to pass on a good deal but...........why risk a gasoline of unknown quality value or make-up in your vintage fuel system.. Hope this information is of some help..

[averagef250]

AV gas never ran right in any high compression engine I had. It smells like VP, but sure doesn't burn like it. I'd liken it to running ethanol based fuel, it doesn't ping, but it doesn't make any power either. I buy VP or 92 with octane boost under 11:1.

[flyboy71]

Av gas will last a lot longer than auto gas in storage but Im unsure how many years. I used to buy extra when I filled my plane to put in my garden equipment for over the winter to prevent "bad gas" in the spring. Av fuel (blue color) is 100 LL (low lead). It contains a small portion of lead because air cooled engines in aircraft need it to allow the valves to seat properly given the loose tolerances. In a car engine you will get a lead buildup on the valve seats over time which is not good. In my plane I lost the #3 cylinder during flight because of a sticky valve so even there its not a good thing to a point. It is essentially pure gasoline with no additives. There is no alcohol like in auto gas because alcohol will destroy the fuel systems in most airplanes. Alcohol is used in auto gas to keep any water in suspension so it flows through the fuel lines, which is why cars no longer suffer fuel line freeze in winter like years ago. They add more alcohol in winter and less in summer. Plus of course there are other additives like ethanol and such. If you have water in Av gas it will sink to the bottom of the tank and coagulate. Pilots drain the fuel system before each flight looking for this water because if it gets to the carb it increases the pucker factor when the engine sputters after takeoff.

Theres my experience with it if its any help.

[70shortwide]

maybe I should come clean about my motor, as it seems some are concerned about it. it is built, sort of. it is a ford racing crate 514. once i do my exhaust (next week, hopefully) it should put down 650 to 700hp. i may be a little optimistic on the numbers, but not completely out of line. we will see.

sounds as though i might be better of to pass on this deal, i would prefer to run race gas anyway. i just wanted to see if i could get by with av gas because of this deal. he says it a year old, i wasnt there when he bought it. id believe him, but even at a year old its only good if its been sealed right. i wasnt there when he sealed it either. ill hang on to my money.

[fordman]

what kind of deal is a good deal for it?

[70shortwide]

a little over $2 a gallon (asking price). last time i bought av gas (same stuff) i paid about $4.50 a gallon...

[flyboy71]

You said 40 gallons? Mix it 50/50 with auto gas and just run it. 40 gallons wont go far in a bump. That little bit wont do much ruin, its if you burn it 100% of the time for years.

[ka_jd7and1]

You said 40 gallons? Mix it 50/50 with auto gas and just run it. 40 gallons wont go far in a bump. That little bit wont do much ruin, its if you burn it 100% of the time for years.

What octane do you need to run with that engine? We mix 110LL AV gas and 93 pump gas for our race car to have higher octane fuel without $8 a gallon price tag.

[70shortwide]

im just thinkin to bring up the octane a little. i dont know much about fuel, other than my truck doesnt really like pump gas so much. itll run on it but not as good and i cant run much timing. the way things are going now, ill be lucky to burn 40 gallons through it this summer . i think it would be fun to put a gallon or two in friends cars and bikes. itd be fun to see if it does them any good. in moderation of course. (mixed)

[flyboy71]

To be honest you wont see too much difference in performance over high octane pump gas. It will burn different and probably hotter so dont get too crazy or you might burn a piston. At the airport they ran the mowers and utility truck on it just because it was there already and they bought it at cost. One thing youll notice is the smell out the exhuast is uniquely different if you run it straight.

Good link to 'splain it better http://en.wikipedia.org/wiki/Avgas

[miner3do]

not completely sure but av gas might still be leaded might be a little better for an older motor but not sure

edit* my grandpa uses the blue stuff in his Cessna it really doesn't look to different from regular gas

[70shortwide]

ive run it before. i was just wondering about how long it can sit and still be good

[flyboy71]

You asked for it so here goes http://www.eaa.org/autofuel/autogas/art ... avgas_.pdf

and another unofficial post http://www.vansairforce.com/community/a ... -9157.html

You asked how long it can sit and still be good? Probably a lot longer than my kids can.