The effects of OLD gasoline in a classic car

[Kern Dog]

Although I enjoy the show, The Walking Dead really stretched the truth in many ways. They had people driving cars YEARS after the world crashed using gasoline that was several years old.
That would never work here in California.
Our gas is "Up to 10% Ethanol". Testing has found it to be approximately 6% as of 2 years ago. I've read that the Ethanol gas has a shorter shelf life than pure petroleum based gasoline.
I have had a persistent cold start problem with my Charger for several months. The last time I drove it to a gas pump was early this year. Since then, I've driven it less than 100 miles. I've been working on several things with it including a new Classic Auto Air heater and A/C system, wiring upgrades, windage tray, radiator, water pump and housing...all sorts of things. Because of that, the gas in the car got old.
So, since about June of this year, it ha been hard to start and when it did, it ran really rough. The Air/Fuel gauge read really lean as well.  It slowly smoothed out as it got up to temperature. Once it was warm, it ran great. The Air/Fuel readings read rich as it warmed up, with numbers in the 12 to 12.5 range.
I looked for the causes of the rough cold idle. First off, I did NOT have a choke on the carburetor. This Demon 850 always allowed the 440/493 to run pretty good at cold starts without a choke. 20-30 seconds of feathering the throttle and it would run on it's own. The rough running felt like a serious misfire, as if 4 holes were just not getting spark. I swapped parts around including the distributor, spark box, ballast resistor, coil and I even tried a different carburetor. The Holley 750 from another car was the only thing that made a difference. With it, the engine ran like it used to before any of the problems started. I had my Demon rebuilt and the man installed a new electric choke kit. Yesterday I put the 850 back on and the car ran just as bad as it did before. What the heck?
It turns out that this 11 month old gasoline was the problem. Today I drained the tank and the bowls of the carburetor and poured in fresh 91 octane gas. The car runs great again.
Why did it run good with the Holley 750? I think that it was because it still had gas in it from the other car!
MY understanding, after reading up a bit, is that as gasoline ages, it evaporates and loses the volatile compounds first.  This leaves behind a thicker, yellower and less potent blend. Cold starts need MORE fuel than a warm start. The fuel needs potency to ignite.
I guess I'll keep some Sta-Bil on hand if I think the car will sit for more than a month.

[Dans 68]

Nice problem solving/starting. Unintended consequences....

Dan

[green69rt]

Although I enjoy the show, The Walking Dead really stretched the truth in many ways. They had people driving cars YEARS after the world crashed using gasoline that was several years old.
That would never work here in California.
Our gas is "Up to 10% Ethanol". Testing has found it to be approximately 6% as of 2 years ago. I've read that the Ethanol gas has a shorter shelf life than pure petroleum based gasoline.
I have had a persistent cold start problem with my Charger for several months. The last time I drove it to a gas pump was early this year. Since then, I've driven it less than 100 miles. I've been working on several things with it including a new Classic Auto Air heater and A/C system, wiring upgrades, windage tray, radiator, water pump and housing...all sorts of things. Because of that, the gas in the car got old.
So, since about June of this year, it ha been hard to start and when it did, it ran really rough. The Air/Fuel gauge read really lean as well.  It slowly smoothed out as it got up to temperature. Once it was warm, it ran great. The Air/Fuel readings read rich as it warmed up, with numbers in the 12 to 12.5 range.
I looked for the causes of the rough cold idle. First off, I did NOT have a choke on the carburetor. This Demon 850 always allowed the 440/493 to run pretty good at cold starts without a choke. 20-30 seconds of feathering the throttle and it would run on it's own. The rough running felt like a serious misfire, as if 4 holes were just not getting spark. I swapped parts around including the distributor, spark box, ballast resistor, coil and I even tried a different carburetor. The Holley 750 from another car was the only thing that made a difference. With it, the engine ran like it used to before any of the problems started. I had my Demon rebuilt and the man installed a new electric choke kit. Yesterday I put the 850 back on and the car ran just as bad as it did before. What the heck?
It turns out that this 11 month old gasoline was the problem. Today I drained the tank and the bowls of the carburetor and poured in fresh 91 octane gas. The car runs great again.
Why did it run good with the Holley 750? I think that it was because it still had gas in it from the other car!
MY understanding, after reading up a bit, is that as gasoline ages, it evaporates and loses the volatile compounds first.  This leaves behind a thicker, yellower and less potent blend. Cold starts need MORE fuel than a warm start. The fuel needs potency to ignite.
I guess I'll keep some Sta-Bil on hand if I think the car will sit for more than a month.

You probably know that modern gas comes with an additive package, that among other things is supposed to prevent the kind of problems you had.  Problem is that the packages have an effective life and how they work also depends on how good (or bad) the original gas mix is, the conditions the gas is stored, etc,etc.  Gum formation, waxy compounds that come out of the gas, evaporation of light components, the effects of ethanol attracting water can all form deposits that need to be filtered, some will even make it thru the filter and deposit in your carb.  Putting in a new tank of gas will help because the gas has a brand new load of additives that help keep all those deposits cleaned up and wash them into your engine to be burned.  This is similar to adding Stabil (sp?), you've just renewed the additive package when you dump in that little bottle.   None of these work forever, ever had problems starting you lawn mover after setting all winter in the garage?  Can be some of the same problems.

[73chgrSE]

My car sat with old gas and without starting it for almost 10 years. Put a new battery in it and it started up. Up to 10% ethanol here in Atlanta area too.

[Kern Dog]

I'm sure that a stock 7.5 to 1, mild cam 318 will run on almost any gas. A 10 to 1 engine with a solid high lift cam is a different animal.

[will]

Now you know what us northeast guys have to deal with, besides salt that murders these cars.

[stripedelete]

I run non-Ethanol and mine doesn't like to start cold.   Not much different than the 76 dart I drove in 1980.

[c00nhunterjoe]

My 11:1 516 headed 383 ran 93 pump gas. Never ran additives, never drained the tank. Never had a cold start issue. Even popped the bowls off and took photos for people on here years back. Longest i typically let fuel sit in it was from the 1st salting til spring. Always kept it topped off through the winter and started it once a month.

[green69rt]

My 11:1 516 headed 383 ran 93 pump gas. Never ran additives, never drained the tank. Never had a cold start issue. Even popped the bowls off and took photos for people on here years back. Longest i typically let fuel sit in it was from the 1st salting til spring. Always kept it topped off through the winter and started it once a month.

Actually, what you did is what is best.  Keeping the tank topped off reduces oxygen from coming in contact with the gas, starting and running for a while then adding gas circulates the gas and adds a little of the additive to the tank to keep the additive level up.  Most important thing is, probably, to keep the tank full.  Prevents Oxygen and humidity from getting into the vapor space in the tank and then mixing with the gas.

[ACUDANUT]

My car sat with old gas and without starting it for almost 10 years. Put a new battery in it and it started up. Up to 10% ethanol here in Atlanta area too.

Yeah, right. 

[73chgrSE]

My car sat with old gas and without starting it for almost 10 years. Put a new battery in it and it started up. Up to 10% ethanol here in Atlanta area too.

Yeah, right. 

No kidding but I did spray some starting fluid in there first.

[c00nhunterjoe]

My 11:1 516 headed 383 ran 93 pump gas. Never ran additives, never drained the tank. Never had a cold start issue. Even popped the bowls off and took photos for people on here years back. Longest i typically let fuel sit in it was from the 1st salting til spring. Always kept it topped off through the winter and started it once a month.

Actually, what you did is what is best.  Keeping the tank topped off reduces oxygen from coming in contact with the gas, starting and running for a while then adding gas circulates the gas and adds a little of the additive to the tank to keep the additive level up.  Most important thing is, probably, to keep the tank full.  Prevents Oxygen and humidity from getting into the vapor space in the tank and then mixing with the gas.

Which is exactly why i did it, and never had a problem and still dont to this day.

[c00nhunterjoe]

My car sat with old gas and without starting it for almost 10 years. Put a new battery in it and it started up. Up to 10% ethanol here in Atlanta area too.

Yeah, right. 

I can beleive it as ive seen it many times. Ive smelled tanks that i swear dont even resemble gas, but junk will fire up. Smokes like hell, runs like crap, no power and pinging. But technically it "runs" i would never do it with something of my own.

[alfaitalia]

I use this on my bikes/cars that I plan not to use for a while. Seems to work OK and is cheap enough.

https://www.wynns.eu/product/fuel-stabilizer/

I don't think the ethanol has much or anything to do with the aging of the fuel. It just happens. I had those issues years before ethanol went into fuel....and still get them now. In the UK not much fuel has ethanol in it yet....with 5% being the maximum legal amount.

[Kern Dog]

I think that ethanol actually does encourage water absorption....which makes gasoline look like Italian salad dressing.

[c00nhunterjoe]

I think that ethanol actually does encourage water absorption....which makes gasoline look like Italian salad dressing.

It does

[alfaitalia]

Absolutely it does.....

https://www.bellperformance.com/blog/4-things-you-need-to-know-about-ethanol-fuel

.....but my point was that as old fuel ages, loses its octane and flammability due to evaporation of the lighter elements (and gets that horrible smell) whether it has ethanol in or not. The hydroscopic nature of ethanol just adds another problem.

[will]

I think that ethanol actually does encourage water absorption....which makes gasoline look like Italian salad dressing.

It does

Wasn't that the reason for Drygas? to prevent frozen fuel lines? That's what I recall, haven't had to use it since Chuck Schumer climbed in my gas tank.

[Kern Dog]

.....but my point was that as old fuel ages, loses its octane and flammability due to evaporation of the lighter elements (and gets that horrible smell)

Before Ethanol was forced upon us, we just had regular old gasoline.
In the early 80s, I used to LOVE the smell of old gasoline. Junkyard gas had a certain "sweet" stench that I really liked.

[alfaitalia]

Im used to that smell and agree.....my work is right next door to a car breakers that's been there since before I was born! Unfortunately its going to be closed and redeveloped for housing. There is going to be a lot of extra cost as unlike modern breakers with plastic lining under the ground this place has 60 odd years of oil soaked into the ground....they recon they will have to remove 6 to 8 feet of top soil to leave clean soil!!

[Kern Dog]

Car breakers?    To me, that sounds funny.
Out here they are called JUnkyards or wrecking yards. Even wrecking yard sounds strange because it sounds like a place where they purposely crash cars.

[alfaitalia]

Yes..it's a pretty British phrase. They all used to be junk yards or scrap yards....and now because they want a greener image they first went  to breakers yards and now most of them are car dismantlers or vehicle recyclers or even automotive metal reclaimers....yeah right!

[c00nhunterjoe]

Its all about going green

[Kern Dog]

Yes..it's a pretty British phrase. They all used to be junk yards or scrap yards....and now because they want a greener image they first went  to breakers yards and now most of them are car dismantlers or vehicle recyclers or even automotive metal reclaimers....yeah right!

They try to call them recyclers here too but being a stubborn traditionalist that I am, I continue to resist.
It runs in my family though.
In the 70s, I recall going with the family to a local river recreation area. My Uncle came over that night and asked what we did that day.
"We went to Negro Bar, Uncle Larry".
Uncle Larry was NOT pleased. "Huh? Its called NIG##R".
Now, the place was then and still is called Negro Bar BUT from the 1850s until the civil rights act of the mid 1960s, the place was named what Uncle Larry said. He was not happy with the new name they gave the place.
Oh, the area got it's name from the Gold Rush era. It was a place where the local government had set aside for the black prospectors to live and work.

[b5blue]

On the topic I ran into this 1946ish film explaining how and why fuels do what they did. Kinda mind bending that adding ethanol is even a "thing" given most is from corn overproduction that's government subsidized. 
https://www.youtube.com/watch?v=NILn0yEzKmQ