Can fuel really go stale ? | FerrariChat

Can fuel really go stale ?

Discussion in 'Other Off Topic Forum' started by Skindiver, Dec 14, 2005.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. Skindiver

    Skindiver Karting

    Apr 22, 2004
    203
    JHB SA.
    Full Name:
    Greg
    In South Africa there is a bit of a fuel shortage at the moment as all stations switch to 'cleaner" heavy metal free fuel, as well as starting to cease supply of leaded fuel entirely.
    Airlines and holiday motorists have been hit with many depots and stations out of fuel.

    Accusations have been flying about directed at the fuel companies that they did not carry enough stock to meet demand during this period. One of the retorts from a fuel company is that it would cost 15% more per litre to stock pile fuel for a years supply.
    It would have been more effective to say that fuel had a limited shelf life and that they cannot stockpile more than a few months supply as it will go stale.

    I know from comments on the internet that Americans all seem to accept that fuel will go off and they add all sorts of additives to prevent that in vehicles bedded down for a long period.

    Besides the US, I have never ever even heard of the concept at all, let alone a widespread acceptance that fuel can go off. Not in South- Africa or any other other country than the US.

    Can it really go off ? Is it only unleaded fuel that goes off ( stale ) ? How ? does it cease to ignite, combust or work properly if its old ?


    Skin.
     
  2. 285ferrari

    285ferrari Two Time F1 World Champ
    Sponsor

    Sep 11, 2004
    20,958
    MD and NE
    Full Name:
    Robbie
    Yes it can go stale--after enough time it will turn to a varnish like liquid. Not sure how it works when it gets to that point. I make sure all my lawn stuff, mower, weedeaters, etc. are empty before storing for the winter..
     
  3. tomberlin

    tomberlin Formula Junior
    Silver Subscribed

    Apr 9, 2005
    849
    Bethesda
    Full Name:
    tom berlin
    What 285 said. Not much is more certain in this world.
     
  4. mk e

    mk e F1 World Champ

    Oct 31, 2003
    13,742
    The twilight zone
    Full Name:
    Help me get this thing finished! https://gofund.me/39def36c
    It doesn't work, all it doesn't is foul the plugs or if you wait long enough the whole fuel system, but that takes many years.
     
  5. Dubai Vol

    Dubai Vol Formula 3

    Aug 12, 2005
    1,418
    back in Dubai
    Full Name:
    Scot Danner
    Fuel goes "stale" because the lighter fractions evaporate off. This happens in cars and lawnmowers because the system is vented, and temperature changes make the system "breathe." When it heats up, the low-boiling-point fractions vaporise and spew out the vent. When it cools down the light fractions condense, which creates a vacuum, so air is sucked into the tank. The air contains water, which diffuses into the fuel. This cycle repeats itself daily, to a small extent, and over the course of the seasons to a larger extent.

    Fuel in hermetically sealed metal containers does not suffer this problem, at least not to anything like the same degree. But the average fuel can is not hermetically sealed. Jerry cans with a good rubber seal are reasonably stable.

    Fuel in plastic containers suffers more than you might think, because plastic is actually porous. Ever wonder why 2 liter cokes are often on sale? It's because the CO2 migrates through the plastic and the coke goes flat over time. Same applies to gasoline, to a lesser extent.

    Bottom line: A fuel depot CAN store fuel for long periods because they keep it in proper containers, i.e. massive tank farms.

    But those tank farms cost money to build and maintain. Ask an oil company to triple or quadruple their storage capacity and they have to pass that cost along to you, and we are talking hundreds of millions of dollars, and except for a special circumstance like the OP describes, that storage capacity is just sitting around being wasted.

    Oh man, chemistry and economics in one post, I must be an engineer!
     
  6. BT

    BT F1 World Champ
    Lifetime Rossa

    Mar 21, 2005
    15,291
    FL / GA
    Full Name:
    Bill Tracy
    While fuel may go bad over time, I think it must be a long time (at least in a warm climate). I have never had problems with fuel turning to varnish and have had lawn equipment and cars sit for at least 9 months without running.
    BT
     
  7. Skindiver

    Skindiver Karting

    Apr 22, 2004
    203
    JHB SA.
    Full Name:
    Greg
    Dubai Vol i tend to side with your ideas in that it makes sense to me that some elements of fuel will evaporate in an unsealed environment ( like most solvents will do, ) and that some stuff will be left behind and get more concentrated per volume. ( the varnish like stuff consistently referred to )

    I also feel that in a well sealed environment it will keep just fine for a reasonably long time. ( years )

    I cant help but get the feeling that many that believe that " fuel goes stale " rather blandly believe that it just has a limited ( and short at that, i.e. over winter ) shelf life sealed or not, and do not consider the evaporation of volatile elements as the cause.

    Skin.
     
  8. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Owner Rossa Subscribed

    May 4, 2001
    36,437
    Birmingham, AL
    Full Name:
    Tommy
    You can tell by the smell. It is really different than "fresh" fuel
     
  9. Glassman

    Glassman F1 World Champ
    Rossa Subscribed

    If you try to start a car with fuel that has turned to varnish you are screwed. The entire fuel system will have to be cleaned out. What it does to carburators is kinda like running enamel paint thru them. Ask me how I know!!!
     
  10. sandersja

    sandersja Formula Junior

    Jan 16, 2003
    367
    Portland OR
    Full Name:
    John Sanders
    Storing your gear with a full tank of gas is the only thing that keeps the (metal) gas tanks from rusting extremely quickly.

    Unless you are talking several years of storage, I do not think that evaporation of "lighter fractions" will be significant since any vent hole is typically very small and the exposed evaporative surface area is very small. The coke-can analogy is (IMHO) misleading.
     
  11. venusone

    venusone F1 Rookie

    Mar 20, 2004
    3,238
    Gas stored over time starts to stink. I mean the odor changes from a fresh hydrocarbon volatile mixture to really rancor icky-stinky. I know, not scientific, but true.
     
  12. Dubai Vol

    Dubai Vol Formula 3

    Aug 12, 2005
    1,418
    back in Dubai
    Full Name:
    Scot Danner
    Good points, but think about what you are saying. If the fuel tank is full, the interior surfaces of the tank are not exposed to atmosphere, so they will not rust. That is good. And if the tank is truly full, the surface area of fuel exposed to atmosphere is also small. Again, good. Less air, with its inherent miosture, in contact with the fuel. But the temperature variations will still boil off the light fractions, and make the fuel less volatile over time.

    I am making qualitative statements, not quantitative statements, because the degree to which these changes affect the fuel is dependent on many variables. I know people who won't let race fuel sit for two weeks, and knowing the fine line that thay are treading on their on-the-edge engines, I don't blame them.

    Best practice is not to let fuel sit around for long periods, and the best way to avoid that situation is to run the engine regularly. Not to mention that regular running lubricates seals, prevents oil from solidifying in critical passages, and generally is the best thing you can do for any engine. Let it sit and it will rot. Same goes for wheel bearings and such. Drive the damn thin already: it's actually GOOD for it!

    [/rant]
     
  13. pete04222

    pete04222 Formula Junior

    Nov 1, 2003
    613
    Maine, USA
    Full Name:
    Peter Cyr
    All fuels, gasoline, kerosene, diesel, etc, are organic compounds that do degrade over time. The molecules react with oxygen and other atmospheric contaminants to form new compounds that change the characteristics of the fuel. It can take as little as 3 months for these new compounds to form. Oxidation inhibitors can be added to fuel, but that makes the cost go up.
     
  14. racerx

    racerx Guest

    Nov 23, 2003
    882
    Very interesting thread. But how does the above make sense if the same person always drives his/her car but keeps the fuel level low, never fills up. Same deal applies the car sits most of the day anyway and then sloshes around for an hour while driven.

    Under the above theory most tanks should rust out fast, driven or not Right??
     
  15. mk e

    mk e F1 World Champ

    Oct 31, 2003
    13,742
    The twilight zone
    Full Name:
    Help me get this thing finished! https://gofund.me/39def36c
    Sloshing prevents that.
     
  16. mk e

    mk e F1 World Champ

    Oct 31, 2003
    13,742
    The twilight zone
    Full Name:
    Help me get this thing finished! https://gofund.me/39def36c
    I learned the same way :)
     
  17. ryalex

    ryalex Two Time F1 World Champ
    Consultant Owner

    Aug 6, 2003
    25,992
    Las Vegas, NV
    Full Name:
    Ryan Alexander
    I didn't know this... I always though it went flat from being too warm and perhaps rattled when shelved. You learn something new on Fchat every day!
     
  18. Erich

    Erich Formula 3

    Sep 9, 2003
    1,190
    Poway CA
    Full Name:
    Erich Coiner
    It smells like paint thinner.

    Erich
     
  19. SrfCity

    SrfCity F1 World Champ

    Sorry you guys are getting screwed like this. They are deliberately reducing supply so that prices can be raised. We just went through a similar scenario and at the same time the oil companies made record profits.
     
  20. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
    Full Name:
    Paul
    First I need to say I live in one of those greatly fluctuating environments. I have seen tamperture swings of close to 100 degrees in one day, between areas less than 50 miles apart. That can build some truly facinating weather. But our greatest obstacle here is winter. From early October to late April, all of our lawn mowers, garden tillers, pressure washers, and of course our F cars or such, are put into dormancy. So which is best, full tank or empty? Well, what I have found, is it depends. I have personally never had any trouble, as long as you get it running the next year. But if it sits one addition winter, without running or getting fresh fuel, it goes downhill rapidly.

    Your machines should be stored inside a dry building, protected from the great temperture changes. Full fuel tanks on a cold day can equal major fuel leakage on a warm day. And once it cools down, no more full tank. And if you fill it up on a hot day, it wont be full when its cold either. The best, is totally empty and run out of fuel, then drain all remaining in lines, carbs, filters, etc. But thats a big hassle. Also, carbs with no fuel in them seem to corrode. So which is worse, gummed up varnished carbs, or corroded fuel bowls? Ive seen a lot of each. But if you just drive out one tank a year, it all works out okay.

    As far as the oil companies, between the governments of the world, and the totally lame liberal self serving idiots who control the media, we will never get a straight story. My Mother taught me as a child, to believe half of what I see, and nothing of what I hear, until I have proof. Its amazing how well that works out.
     
  21. lusso64

    lusso64 Formula 3

    Apr 12, 2004
    1,535
    Simi Valley
    Full Name:
    David
    This happened on the Lusso. Nothing short of stripping the carbs and replacing fuel lines and filters will fix it once it has happened. Even then, there will always be that little bit that keeps blocking something in the carbs. This can go on for YEARS if the car is still not used that much....
     
  22. tedwentz

    tedwentz Karting

    Aug 29, 2004
    64
    Mid Atlantic USA
    Full Name:
    Ted Wentz
    Like many things in life your fuel should pass the sniff test.
    Before firing up any car/lawnmower/weedeater/motorcycle/boat/generator or gas powered margarita blender that has been sitting for a while you should smell the fuel first. The gas should still smell like gas, if it has a slight or a strong paint thinner smell do NOT start the motor.
    The good news is that you can put Stabil in the fuel for long layups and rest easy.
    FWIW, I've never had untreated fuel go bad after one winter of layup.
     
  23. lusso64

    lusso64 Formula 3

    Apr 12, 2004
    1,535
    Simi Valley
    Full Name:
    David
    The big problem I faced was that I did not know what California gas is meant to smell like! To me, it all smells weird. In Australia, well, it smells like petrol!

    On a closely related note, back in Australia I would happily use petrol/gas as a solvent when stripping most engine parts and would not wear gloves etc. I tried that once here and my skin got inflamed and itchy for a few days. The stuff is like acid.

    I wonder if the "going off" problem is in some way related to some of the wonderful chemicals that are added?

    Dave
     
  24. Skindiver

    Skindiver Karting

    Apr 22, 2004
    203
    JHB SA.
    Full Name:
    Greg
    For those of you that have first hand experience of fuel turning to thinners or varnish or enamel like paint, how long did the car stand for ? How old was that fuel ?

    So far we have some testimony that one winter ie six odd months was fine, possibly even the next summer ie another six months was also ok, but another winter ie. a total of 18 months started to prove problematic .

    Skin.
     
  25. dpospres

    dpospres Formula Junior

    Jun 29, 2005
    275
    I was always told in the boating world, that depending on the container that the fuel is stored in, it can lose up to 1 point of octane rating per month.
     

Share This Page