Which weight more, bad gas or fresh gas?

[cudaken]

 Today I played with my 68 Road Runner that slept 8 years. Jim and I pumped out 6 gallons of foul gas. Over 3 to 4 mouths I have added 10 gallons or so of fresh gas with some fuel stabilizer, was not sure if we added sufficient amount. Today I added another 2 gallons with 6 oz of fuel stabilizer.  

When I first start her up, gas stinks a lot (Not as bad as first start up) then after running a while gas does not smell as bad?   Run her till she is out of gas, or keep adding till the smell is gone?

What are your thought besides dropping the tank? I would love to, but with out help it is not gone to happen.

Cuda Ken

[Kern Dog]

The question in the title doesn't correspond to the subject in the thread. 

Gasoline weighs 6 lbs per gallon whether it has gone bad or is fresh from the pump.

[metallicareload99]

My guess is bad gas

[RallyeMike]

A car with bad gas in it weighs more than a car with good gas in it. This is particularly true if you happen to be in the passenger seat of the car with bad gas in it.

[cudaken]

 Boy, I did miss the point I was asking about.  

I was wondering if bad gas weights more than fresh gas. Reason when I first start her up, the bad gas smell is more noticeable. If bad gas weights more then it is on the bottom of the tank and gets picked up first so more of a smell?

Cuda Ken

[PlainfieldCharger]

The gas will mix buts needs some movement. Old gas does not burn as complete as fresh gas (why you smell it so much). Does you car have a fuel sending unit with a return line? If it does, keep it running and this will "mix up" the fuel you have in the tank. Siphon some more from it till you get enough fresh mixed in.  Also, do not use the "old gas" in a small engine like a lawn mower or snow blower. Small engines do not like Old gas at all....If the old gas you have is reg unleaded but it in your daily driver a gallon at a time to use it up.

[XH29N0G]

Usually fluids like old and new gas that dissolve into each other will eventually mix.  This is due to the fact that simple random movement of the molecules can overcome the forces that would cause them to separate by mass.  In some cases, there can be a density stratification that is maintained.  This often happens when there are two fluids that do not dissolve into each other but are immiscible (like oil and water).  In this case they would not mix. 

If there is a chemical change in the gas (maybe even just absorbing or releasing water vapor or losing some more volatile component) then I would suspect there may be a difference in the density of old and new gas, but I would think this would be a very small difference.  I would also think that adding new gas to old gas would result in mixing pretty quickly where the new density would be something different (probably in between the two).

A chemical change might make the gas burn differently or smell differently or have different smelling products.  My guess is that if it will run, it will be OK to burn through the engine (others may know differently) and then with new fills you will be OK. 

[Ghoste]

If you have stale gas in the tank you have it in the whole fuel system.  It will take a couple of tanks to burn through before that foul stink is gone.  If it has been sitting in there a long time, you will have varnish deposits (I call it varnish anyway) in the fuel system as well and a carb rebuild will be in order.  If itts been a really long time sitting there will also likely be deposits sitting in the bottom of the tank and then you are looking at a fuel system flush.

[green69rt]

I started to write a really long reply on the properties of gasoline (snooze!!) but realized that the basic question is what to do about suspicious gas.  If you got it you need to get rid of it.  It can foul up the whole fuel system.  Disconnect the gas line from the sender, hook up another line to the sender and drain the gas as much as you can.  Use it as solvent or find a way to dispose of it but don't run it thru any engine.  Would you risk a carb rebuild for $30 worth of gas??  Change the fuel filter (or add one if you don't have it), fill with new gas and go!  If it doesn't run well then you may have more work ahead of you to get rid of the deposits left behind.

New gas has a boatload of detergent in it and should help get any remaining crap out.

[Ghoste]

I can't even stand the stank to use it for paint thinner personally.

[green69rt]

I can't even stand the stank to use it for paint thinner personally.

Yeah, it is pretty rank, the sulfer makes it stink.  In Houston, there are hazardous waste collectors that would take it off you hands.

[XH29N0G]

Yeah, it is pretty rank, the sulfer makes it stink.  In Houston, there are hazardous waste collectors that would take it off you hands.

I actually would be interested in learning about what happens to the gas (long story) and also what the sulfur chemistry is that makes it stink.   Can't help it.  I love that element.

[cudaken]

 One of the reasons the Road Runner sat so long was due to the fact the fuel pump gave up while the 750 Holley was on a different car, so Carb was clean on the inside.

When Allen and I started her for the first time after 8 years we used fresh gas out of a 2 gallon can. Next Jim and I gravity feed the Road Runner and used the new fuel pump to pump out the foul gas. We got close to 6 gallons out. That crap goes a few litters at a time to a friends shop old oil storage tank, and that stuff is ripe!  

My fuel system has no return line, but I normally move her while she is running.

Looks like I am getting a new gas tank. Some of the folks that have been following my Adventures with Miss Lumpy http://www.dodgecharger.com/forum/index.php/topic,101965.0.html
have bought her a new gas tank and sending unit!  

Is there anything I can add to the gas to help clean out the fuel line till I can replaces it?

Cuda Ken

[Ghoste]

Probably too late for that now.

[green69rt]

If anything comes out of the line it should be taken care of by the new gas detergent, other wise you'll know something's wrong pretty quick.  Might be a good idea to run a little fresh gas thru the lines before you hook them back up.  Probably be fine.  Obviously you need to have a clean fuel filter?   Does your Holly have that brass inlet filter??  If so it might be good to check it after running for a while.

[green69rt]

Found this...

http://autos.aol.com/article/does-gas-go-bad/

One thing the article doesn't talk about is the sulfur in gas.   That's because there is almost none in modern gas.   The refiners had to take it out so Cat Converters would last.   Old gas had a lot in it (remember how some cars would fart out a rotten egg smell when converters first started coming out, that's the sulfur.)    Refiners were forced to reduce the sulfur content to less than 30ppm, starting in 2004.   At one point they could have 500ppm (I think.)  So modern gas is really clean but still suffers form such problems as oxidation, water contamination and the ethanol mandate has raised even more issues.

By the way, it's the conversion of sulfur to hydrogen sulfide in your engine that makes the stink.

[john108]

My charger sat for more that ten years.  The older I get, the less I remember how long.
I recently drained the tank and foolishly tried to run the gas in my lawn mower.  The mower didn't like it and had to be flushed out.
The inside of the tank had no deposits and was very clean.

[cudaken]

Green, I have not thought about the built in filters, might be worth a look. So far the carb seems fine.

Main reason the folks chipped in for the new gas tank is because of rust.

http://s83.photobucket.com/user/cudaken/media/Charger%20Site/11-13-1_zps94596329.jpg.html]

While I was not total convinced I need a new tank, mine is around 10 years old,  they where. So I have a new gas tank sitting in the living room.  More than likely they are right. Last time I let a Mopar sit for some time was before the EPA made it better by adding Corn to Gas.

Cuda Ken

[heyoldguy]

I've fired up several cars that have set for years before they put the ethanol in the fuel. After returning them to service the problem I had was the ethanol scouring out all the rust from the lines and tank. I would have to replace one or two plugged fuel filters and then the cars/trucks have run fine since.

[Ghoste]

Not on topic but what is it about the ethanol that makes it scour the tank?

[green69rt]

Not on topic but what is it about the ethanol that makes it scour the tank?

There was a change in the US gasoline detergent standard about 2004.    So called "top tier" detergent gasoline standards were enacted.   If you look at the timing of that standard and the ethanol mandate, it may seem to be related but I'm not sure.    Anyway, at that point some gasoline manufacturers greatly increased the amount of cleaners in the mix.   This change may have some effect on rust but seems kind of odd.  Maybe just a happy coincidence??