A gasoline question!

[Sarikatime]

I have thought about this for a long time but it is time to ask those who know better than me.
We drive our toys once in a while or less, and fill gas into the tank rarely. I use regular gas to fill up before a tour or when I don’t want to be stranded without gas around town. Now, there is obviously some or several gallons that have been in the tank for a while, depending on when you drove last, but as I was told, gas deteriorates after some time. How long is it till it is less powerful, a week, a month, six months, a year? If I were to have three gallons of gas in the tank for the last three months that is stale gas? If I were to add equal amount of premium gas to the stale gas, would it perk up the old gas as it mixes, would it mix, or would it pep up the whole lot and act like fresh gas? Or is this a useless topic to worry about since I fill up to the top before a major drive like a tour? Will the regular gas, even a half full tank, after filled to the top mix enough that will not make a difference in performance? I realize that with a model T, not much will make a difference, unless high performance equipment has been added at a great cost.
Please chime in with words of wisdom. Thank you, Frank

[Steve Jelf]

Since Shorty was a pup I've been reading horror stories of gas gone bad. It's never been a problem for me because I drive enough to use it up. Going to the market for milk? Drive the T. Going to watch the fireworks show? Drive the T. Going down to the prairie preserve to see the bison herd? Drive the T. How long does it have to sit before it goes bad? Beats me.

[big2bird]

As a general rule, 6 months. Longer than that add a touch of Sta-Bil.
Regular is fine. Premium is just wasting $$.

[speedytinc]

Given your parameters, you have nothing to worry about.
Gas (here on the left) starts going bad after about 6 months. I find a noticeable rough running after a year in modern motors. Topping off with fresh gets a good running motor back. Half tank or more old gas, I do refill with premium.
In the T's, I run the carbs dry after every drive just in case I dont drive that T for another 6 months to a year.
Also, I & others have noticed the volitals will evaporate out of T carb bowls rather quickly (2 weeks or more), causing a harder starting condition until the bowl refills with "fresh" fuel. A second reason to run the carb dry.

[WillyR]

The ethanol is what gets nasty sooner than the guzzoline....

I dump a half a quart of marvels in the tank if I don't remember when I drove it last on my other cars. then top off the tank.

I try to rotate cars monthly but one time I let my 65 sit for 6,9,12 months when I didn't wat to rebuild the carb...

[TRDxB2]

The issues with Ethanol gas will never be agreed upon. But here is some information relative to it

I asked the AI Bot and I believe it is an accurate description of what CAN happen. NOTE: It says that stratification occurs when the gas comes in contact with water - not on its own. So the biggest issue is what might cause condensation in the vented tank (the small hole in the gas cap). Humidity & temperature changes.

AI BOT
"Yes, ethanol gas can stratify, particularly when it comes into contact with water, causing a "phase separation" where the ethanol and water separate into a distinct layer at the bottom of the fuel tank, leaving a layer of relatively pure gasoline on top; this can happen when enough water contaminates the fuel, and is a key concern with ethanol-blended gasoline, especially in situations where the fuel is stored for extended periods or exposed to moisture"
"A typical ethanol gas blend, like E10 (10% ethanol), can absorb around 0.5% water by volume before reaching its saturation point and causing "phase separation", where the water separates from the fuel and forms a distinct layer at the bottom of the tank; this translates to roughly 3.8 teaspoons of water per gallon of fuel at 60 degrees Fahrenheit"
"Ethanol evaporates relatively quickly when mixed with gasoline, generally faster than the other components in gasoline, but not as fast as pure ethanol on its own; in a typical scenario, a significant portion of ethanol in a gasoline blend would evaporate within a few hours, especially when exposed to high temperatures and air movement"

--
Last year, as an experiment, I put some 10%Ethanol gas in a vented jar outside. Never observed "phase separation" over the summer months. So did the ethanol evaporate before it has a chance to absorb water? This year I used last years gas in my 2 stage snowblower - no trouble starting it. Nver used Sta-Bil.
--
Remember the product "HEET" was used to unfreeze gas lines (Active ingredient: Methanol or isopropyl alcohol) but it isn't the alcohol, ethanol, in gas. Methyl alcohol (methanol) or isopropyl alcohol, which all act as a fuel additive that absorbs water in the gas tank. These alcohols are not the same as Ethanol

[Norman Kling]

My only experience is with California blend gasoline. We have a summer blend and a winter blend. This has been my experience. When the gas gets old, especially in a partially filled tank. The car sets many months, like a year or more. In that case it is a good idea to drain the tank and run the engine till the carburetor is dry. also drain the sediment bowl. The cars I drive regularly have not had problems, but if they are not used for a long time such as a year or more, the gas actually gets thick like shellac and a wire needs to be run back and forth in the fuel line. Then the line blown out with compressed air. The carburetor also needs to be cleaned completely including all the small passages and vent holes. This gas will actually thicken. Especially if you have a filter other than the sediment bowl, it is hard to get gas through it and can cause starvation especially going up hills. Anyway, that is why I try to rotate the cars I drive and use them at least once a month.
Norm

[TRDxB2]

Norm brings up another variable to stored gas. Is it the Winter or Summer blend......

AI BOT
"The primary difference between winter gas and summer gas is the "Reid Vapor Pressure" (RVP), which measures how easily fuel evaporates; winter gas has a higher RVP, allowing it to vaporize more readily in cold temperatures and start a car easier, while summer gas has a lower RVP to prevent excessive evaporation and smog formation in hot weather"

Winter gas often contains more butane, a highly volatile compound that helps with cold starts.
Summer gas is designed to reduce emissions like smog by limiting evaporation in hot temperatures.
Winter gas is usually cheaper to produce than summer gas.

Sounds like "Winter Gas" doesn't store well

[TXGOAT2]

How quickly and how badly ethanol-adulterated gasoline will deteriorate depends on many factors. The specific blend and quality of the gasoline can be a factor. The temperature, elevation, and ambient humidity are all factors. Whether the tank or container is vented or not affects it. Sunlight degrades gasoline. Stale gasoline can destroy a fuel system as well as causing hard starting, no starting, and problems like stuck valves. It's best to use gasoline within 30 days or so of purchase, and a Model T in storage ought to have the fuel used up or drained while it is still fresh and used elsewhere. I don't think premium would offer any advantage over regular to dilute stale gasoline. Far better to keep stale fuel out of the system, period. It can do far more damage than the cost of the fuel "saved" could ever justify.

[TXGOAT2]

Gasoline today is designed for closed fuel systems with fuel injection. It works well in a T, as long as it is fresh. It can cause issues with vapor lock and carburetor boil-over in older, carburetor equipped vehicles with engine-mounted fuel pumps. The winter blends are worst in this respect on warm winter or spring days.

[RecklessKelly]

If I think the gas will stand for more than a month, I add Stabil to it. I run the carb out of gas every time and I've rarely had a carb go south after I initially went thru it. Coming home in my T, I usually stop in the road right in front of my driveway and shut the gas off and at the top of the drive, it starts to run out. I let it idle until it stalls out.

[Russ T Fender]

My experience with ethanol fuel is that a powdery substance developes eventually that clogs the small passages in the carburetor. The gas is volatile enough even after sitting for a while and is probably still better than anything the car was designed to run on back in the day. I finally got tired of rebuilding carburetors and now only use non ethanol gas and have no more issues.

[Rich P. Bingham]

Perhaps I’m mistaken, but over time, posts about gasoline seem to indicate fuels may vary a lot regionally. Ten years or more back, I found ethanol blends caused me a lot of problems with my small engines. Changing to non-ethanol solved my problems, so I’ve adopted it for my Model T too.

Re/ the problem of fuel degrading while your car is stored, I don’t understand why folks don’t just drain the tank and the carb over winter, or whatever. Is there some reason that’s inadvisable ?

[Norman Kling]

Another problem not mentioned above. On one of my T's I had trouble starting. The choke valve was stuck and flooded the engine. or the choke would not close and needed to be primed. I had to spray on some acetone or carb cleaner and work the choke loose so it will open with the rod or wire and close by the spring when I release it. I have not had problems with more modern cars such as my pickup which was stored for almost a year until I replaced the battery. I got it started when I got a new battery and it started up and passed the smog test with the old gas in it
so I could renew my registration. Now I drive it at least once a week.
Norm

[TXGOAT2]

Handling gasoline is hazardous unless all proper precautions are not taken. That said, I'd use up or drain the gasoline from a Model T or A that is to be stored while that gasoline is still known to be fresh. If you use care and clean containers, the drained gasoline can be safely used in another vehicle.

[TXGOAT2]

Gasoline stays fresh longer in modern, unvented fuel systems with vapor-tight caps. But it will go bad eventually. I believe that gasoline goes bad sooner in motorcycles and small engines. Many of these have vented fuel systems, and when they are in use, they often get the gasoline in the tank rather hot and also subject it to strong vibration. That can drive off co-solvents and other fractions of the gasoline blend.

[jiminbartow]

Ethanol free gas lasts much longer than ethanol gas. To locate ethanol free gas in your area. Www.pure-gas.org.

[Charlie B in N.J.]

According to every small engine manufacturer that I have attended classes at for warranty certification gas begins to deteriorate in 90 days. This is universal across them all. Extensive testing also shows that gas can’t be “preserved”. In other words crap like Stabil is snake oil.

[TXGOAT2]

Gasoline isn't new when you buy it. It has been in storage for some length of time, and all gasoline is not stored and handled under the same conditions. High volume retailers usually have "fresh" product. Name brand gasolines may be handled and stored with more care than no-brand fuels and may be more consistently formulated. Many pumps in this area are labeled: "PRODUCT MAY CONTAIN UP TO 10% ETHANOL". In some cases, a vendor may offer "ethanol-free" gasoline at a substantially higher price. That discourages volume sales, especially in winter, when many boats and small engines are out of regular service. That can lead to old product. Fresh gasoline is ALWAYS the best choice. "Tier One" fuels are of better quality and more consistent formulation than some other fuels. They can often be found at competitive prices.

[TXGOAT2]

Older retail facilities with underground tanks may have water in the tanks. Above ground storage tanks are subject to heat in summer, and water condensation can be an issue all year in some localities. Any or all of these situations can degrade the product prior to sale.

[John Codman]

Ethanol free gas lasts much longer than ethanol gas. To locate ethanol free gas in your area. Www.pure-gas.org.

I do use Ethanol-free gas in my T, but the drivers get the normal Ethanol added gas. When I lived in Massachusetts non-ethanol added gas was not allowed to be delivered into registered automobiles. You could buy super-expensive race gas, but not normal ethanol-free gas. I agree that ethanol-free gas lasts (stores) longer the Ethanol added gas.

[Art M]

Up until about 4 years ago, I used non alcohol gas in the model T. The price jumped from 50 cents per gallon to a dollar difference in price compared to regular ethanol gas.

During winter storage I fill the tank ethanol gas and treat it with Sta-bil. I drain the gas in the carburetor. If needed, I can use this stored gasoline in the standby generator if needed.

Art Mirtes

[Steve Jelf]

[JohnH]

I use E10 in my T. The longest I haven't driven the car is two months, and never had a problem. My lawnmower fuel might sit for 6 or more months and is also E10. Again, no problem. On that note, a few years ago, I had a quantity of old fuel which had sat in a more modern car for something like five years. It had changed colour and absolutely stank. The question was, how to dispose of it? Knowing the Model T is not fussy, that's where it went, and I have to say it never ran better.

[Craig Leach]

I don't know were you would get this information now days. when I had connections in the petroleum industry I found out that all the gas comes
down the same pipeline & the differences are time & treatment. some gas companies put additives to improve performance & stability & some
will pay more to get the gas as soon as they can, while others will wait to get a better price. I have found that Chevron will go for the freshest &
do a good job of treating their gas. Your findings may vary. Gas from my local Chevron will stay fresh 2-4 months longer than most of the others.
As far as treating yourself I have found many additives that work good for me some are Sea-foam, Star-Tron, both look and smell similar. Stabil
works well & so does the Briggs & Stratton. For two stroke mix I prefer synthetic castor oil, it lubricates excellent and preserves. I over treat
my fuel if I think there is a chance it will not be used for some time. I have no issue with storing gas for 18 months in 5 gal. race jugs stored
out of the sun light. I find that storing gas in a vehicle with a carb that can gravity feed will allow the gas to evaporate threw the bowl vent
leaving behind a build up of nasty stuff that gums up linkage & jets. I have a downer pickup & a boom truck that need to be moved from time
to time that using Sea-Foam have not been to a gas station in many many years & start right up every time the battery is not dead
I run synthetic castor for a upper cylinder lube in my speedster & it's fun to watch peoples noses go up trying to figure out what that funny
smell is. If you use castor in two stroke weed eaters & chain saws, if you don't smell the castor when you start it up shut it off you put the
wrong gas in it.
Craig.

[TXGOAT2]

To sum up:
There is no fixed time line for how long gasoline, especially ethanol-adulterated gasoline, will stay in good condition.
Bad gasoline can do A LOT OF DAMAGE and it can cause a LOT OF ISSUES short of actual damage.
Model Ts only hold about 10 gallons of gasoline maximum.
It's best to use it up or drain it before storing the car over 6 weeks or so.
Storing gasoline can be dangerous, and stored gasoline can lose quality or become worse than useless due to decay.
Model Ts are equipped with the means to drain residue fuel and condensate water from the fuel system.
For most people, there is no need to store gasoline for long periods of time, so why do it?

[Charlie B in N.J.]

I'm with Pat above. If you are in a longer that usual storage situation AT THE VERY LEAST keep the fuel out of the rest of the fuel system. IE: drain the carb although opening the valve and letting that old fuel back into the system doesn't sit well with me and kind of defeats the purpose. The motto of that small engine shop I worked at after I retired was "If it ran before you drained it it'll run when you refill it". Fresh fuel of course. Very very few listened. They wanted a full tank with stabil in the gas. We usually saw them again when the new season started. Especially the snow blower folks.

[Art M]

I use aviation fuel in the my snow blowers and in the chain saws. I don't run out the gas when i put them away. They always easily start when needed.

Art Mirtes

[TXGOAT2]

Av gas is great, if you can afford it. The lowest octane Av gas available is fine for a Model T or any pre-1955 car.

[CALLEN1234]

I use recreational gas in my Model T, boats and outdoor equipment. I do not have any issues. Aviation gas is great if you can get it.

[Art M]

Boat gas and Av fuel are about the same price in my area.
The Av fuel I can get is 100 octane is supposed to be good for 10 years. I have had good luck with ethanol gas in the model T. I drive about 2000 miles between April and November, so the gas stays fresh in the summer.

Art Mirtes

[Sean Butler]

I am lucky enough that the closest gas station to me offers ethanol free. My question is if I'm out on a long run and need to refuel and there is no ethanol free in sight, what are the potential consequences? Am I safe to run "normal" gas and just flush it "clean" with ethanol free when I get low? I run a Stromberg OF carb.

[TXGOAT2]

A T will run just fine on E10. The only issue is that it can decay over time, usually several months.
Non-ethanol gas will probably last better, give a little more power and MPG, and may make starting the car a little easier.

[TXGOAT2]

"E10" may or may not contain 10% ethanol.
"E10" is supposed to mean that it is 10% ethanol OR LESS.