Gas tank vent tubes and lines

[Roadtrip]

A few folks have tossed around the idea of newer gas causing more vapor than can vent rapidly. I think maybe I need to start believing that as I truly can't figure anything else out?
The one gas station I buy my premium off of is not supposed to have ethanol in their premium unleaded.
Maybe I will try a different gas station next time I take on fuel.

 

[69hemibeep]

A few folks have tossed around the idea of newer gas causing more vapor than can vent rapidly. I think maybe I need to start believing that as I truly can't figure anything else out?
The one gas station I buy my premium off of is not supposed to have ethanol in their premium unleaded.
Maybe I will try a different gas station next time I take on fuel.

Let us know how it works!

 

[Roadcuda]

I get the smell of gas also, mostly just after using the cars. I've had people ask me if the cars have a gas leak and I know that they don't. They often sit in the garage for a week or more before I use them again the smell of gas is gone.

 

[Roadtrip]

Put about 8 gallons in of a different brand tonight and cruised around with a buddy for about an hour tonight. When I dropped him off I immediately went to the tank, no bubbling, and no pressure when I removed the cap, and no leaks.

Drove a short distance to my house and there was a tiny bit off pressure, again, after I pulled up the incline of my apron to park in my garage. I think if the fuel sloshed to the back and enters the long tube in the tank it changes the dynamic of the venting and creates a temporary blockage of the one line and pressure starts to build. Not sure, but this is the best I can make of it for now....?

 

[WILLIAM PURCELL]

Don't you mean left to right? (Not right to left as you wrote)
Isn't the tank internal line that is closest to the sender the long line that connects to the short J line outside the tank? Then the line that goes to the trunk connects to the internal short line?.

what is this difference between the long an short ?

 

[Roadtrip]

Not too sure what you mean by difference other than the obvious differences of the lengths. Are you familiar with how the vent lines run? Then maybe we can answer your question a little bit better

 

[69hemibeep]

Took a small survey at a Mopar show last weekend and found that drivers of cars with Carter carbs have stinky garages and after a few days the carb is to dry to start properly. Drivers with Holley carbs have better smelling garages and cars that start. I have 2 here with Carters and one Holley same results

 

[Roadcuda]

Took a small survey at a Mopar show last weekend and found that drivers of cars with Carter carbs have stinky garages and after a few days the carb is to dry to start properly. Drivers with Holley carbs have better smelling garages and cars that start. I have 2 here with Carters and one Holley same results

It's nice to know that I'm not alone!

 

[‘69_Sunfire_RR]

Question about the vent tubes on the ‘69 RR. How do they route? From the pic it looks like one just routes into the trunk then dumps back out, venting into the atmosphere. The other is shorter and just vents close to the tank? On some of the other B bodies, looks like the vent tubes route to the filler neck? My ‘69 RR has a strong fuel smell while stored in the garage. No leaks, new cap. Suspect vent tubes.... can anybody comment? Thank you all!

 

[69hemibeep]

Both vents go to the atmosphere. In the tank the short one vents uphill the long one vents down hill in theory but they will get gas in them with a full tank then they don't vent until the gas gets pushed out with pressure do to exhaust or road heat or it drains back. The short one in the tank goes up into the trunk and back down into the frame. The long tube in the tank goes to the short vent that looks like a ? or an upside down J. The gas in Carter carbs evaporate out over 3-4 days(stinky) Then you have long cranking to fill the carb back up.

 

[TOMRR]

Both vents go to the atmosphere. In the tank the short one vents uphill the long one vents down hill in theory but they will get gas in them with a full tank then they don't vent until the gas gets pushed out with pressure do to exhaust or road heat or it drains back. The short one in the tank goes up into the trunk and back down into the frame. The long tube in the tank goes to the short vent that looks like a ? or an upside down J. The gas in Carter carbs evaporate out over 3-4 days(stinky) Then you have long cranking to fill the carb back up.

SORRY !! to jump on this thread, but what are other systems if the
vent lines are reversed I just put a new tank in my RR in hooked them up the way are supposed to be.I never looked in tank before install

 

[69hemibeep]

Mine would pee on the differential after I parked it if the tank was any where near full threw a vent leaving a puddle about 6" in size.

 

[Blacktop Voodoo]

Mine would pee on the differential after I parked it if the tank was any where near full threw a vent leaving a puddle about 6" in size.

I know this is an older thread, but you just described my current issue. My car did the same thing yesterday after I filled the tank. I smelled gas and saw a puddle under the differential. I crawled underneath and found it was coming from a vent line.

 

[Blacktop Voodoo]

I found that I should not "top" off the tank. Drove it about 5 miles to lower the tank level---no more dripping from vents. Temps have been hot here and I think that also contributes to fuel leaking from vents due to expansion.
Ken

 

[IRON MAN]

Do you need the vent lines I have a 3/8 fuel line and 1/4 vent line I thought the 2 vent lines were for California cars only back in the day?

 

[Rapid Transit]

No.
Many cars had vent lines.
What year and engine?
Go here and see if your answer is there,
https://www.69roadrunner.net/mopar/threads/where-do-the-tank-vent-lines-go.18003/#post-199080

 

[Russ69Runner]

Vented fuel cap also vents lines. Stop the tank from having too much pressure in it or stopping the flow of the fuel due to vacuum created at the tank.