The Ford Barn

nkaminar · 02-28-2024, 08:59 AM

A little history may help. When cars first started burning gasoline it was more or less a single molecule. As more and more cars were built to burn gasoline, heaver molecules were mixed into the fuel. The octane rating suffered and compression ratios were reduced to compensate and the air/fuel going into the engine was heated to help vaporize the fuel. At this point storage was not a problem.

Now petroleum is cracked, which means the heaver molecules are broken down into lighter ones and the fuel is a mixture of many different molecules. Lighter molecules are there that vaporize easily to help the car start. The heavier molecules are there to fill out the fuel and make it cheaper to manufacture. The ethanol is there to also fill out the fuel and increase the octane rating.

What this means is that as the fuel ages, the volatile components evaporate leaving the heaver ones behind. These heaver molecules are really tar that can gum up the works. The ethanol attracts moisture and can cause corrosion.

I don't have a magic solution, but try to run my car throughout the year and put fresh gasoline in it. I know that is not possible for some people.

Steve in Denver · 02-28-2024, 10:24 AM

In Denver, there are Murphy's gas stations, they carry an Unleaded Ethanol Free gas, 87 octane. It is the one with the Blue handle.

Tim Ayers · 03-05-2024, 09:48 AM

Quote:

Originally Posted by updraught

Because it is making Americans less and less intelligent it says.

LOL! Consider me a dumb ass because I'll mix a little 100LL into my non-ethanol gas. Granted, I'm running a highly hopped up flathead V8 in my '28 roadster, but the engine does like that mixture of 9:1.

Herb Concord Ca · 03-05-2024, 05:46 PM

I've given up on the tank or firewall valves. Both my cars have ball valves in the line up close by the sediment bowl. Have not had a problem in15 years.

ModelA29 · 03-07-2024, 01:05 PM

100LL = 100 octane Low Lead aviation fuel. It's good fuel and has a longer shelf life. Do not use it in a car with a catalytic converter. The lower vapor pressure is so it's easier to start. My plane was certified to run car gas. The only change was a brass float instead of a plastic one in the carb. Here in CA it's our only option to get ethanol free fuel. It's only "illegal" to run on the highway because you didn't pay a road tax to use it on the street - kinda like an electric car......

Lead in gas acted as a lubricant for the valves and seats. New cars have hardened seats to reduce wear. Model As do not have enough valve spring seat pressure to have a wear problem. The low spring pressure also means you don't need zinc in the oil to protect the cam and lifters.

I always add Stabil to my Model A. A tank of gas can last me up to 3-4 months depending on weather so better safe than sorry with today's garbage fuel.

Gene F · 03-07-2024, 07:21 PM

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Quote:

Originally Posted by Steve in Denver

In Denver, there are Murphy's gas stations, they carry an Unleaded Ethanol Free gas, 87 octane. It is the one with the Blue handle.

I wonder how that grade compares in price.

02-28-2024, 08:59 AM	#21
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: fuel shelf life in tank A little history may help. When cars first started burning gasoline it was more or less a single molecule. As more and more cars were built to burn gasoline, heaver molecules were mixed into the fuel. The octane rating suffered and compression ratios were reduced to compensate and the air/fuel going into the engine was heated to help vaporize the fuel. At this point storage was not a problem. Now petroleum is cracked, which means the heaver molecules are broken down into lighter ones and the fuel is a mixture of many different molecules. Lighter molecules are there that vaporize easily to help the car start. The heavier molecules are there to fill out the fuel and make it cheaper to manufacture. The ethanol is there to also fill out the fuel and increase the octane rating. What this means is that as the fuel ages, the volatile components evaporate leaving the heaver ones behind. These heaver molecules are really tar that can gum up the works. The ethanol attracts moisture and can cause corrosion. I don't have a magic solution, but try to run my car throughout the year and put fresh gasoline in it. I know that is not possible for some people. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 03-05-2024 at 06:34 PM.

03-05-2024, 05:46 PM	#24
Herb Concord Ca Senior Member Join Date: May 2010 Location: Concord CA Posts: 637	Re: fuel shelf life in tank I've given up on the tank or firewall valves. Both my cars have ball valves in the line up close by the sediment bowl. Have not had a problem in15 years.

03-07-2024, 01:05 PM	#25
ModelA29 Senior Member Join Date: Sep 2022 Location: SoCal Posts: 591	Re: fuel shelf life in tank 100LL = 100 octane Low Lead aviation fuel. It's good fuel and has a longer shelf life. Do not use it in a car with a catalytic converter. The lower vapor pressure is so it's easier to start. My plane was certified to run car gas. The only change was a brass float instead of a plastic one in the carb. Here in CA it's our only option to get ethanol free fuel. It's only "illegal" to run on the highway because you didn't pay a road tax to use it on the street - kinda like an electric car...... Lead in gas acted as a lubricant for the valves and seats. New cars have hardened seats to reduce wear. Model As do not have enough valve spring seat pressure to have a wear problem. The low spring pressure also means you don't need zinc in the oil to protect the cam and lifters. I always add Stabil to my Model A. A tank of gas can last me up to 3-4 months depending on weather so better safe than sorry with today's garbage fuel. Last edited by ModelA29; 03-07-2024 at 01:10 PM.