Gas Tank Vent

Guys,
I can't find much in the archives on this one, so I'm looking for some advice and pictures. How have most of you handled your gas tank vent? Is it just an open hose into the wheel well or are there any creative solutions out there? Anyone vented back into the filler tube allowing the airflow through the cap to eliminate suction while containing vapors?

I know the open ended hose works, but it seems like there should be something better.

Brian Carlson

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

Brian,

Here's a photo of mine.... sorry about the size, I don't know what happened?!?

http://www.uniquecobra.com/uploaded/...tank vent1.JPG

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

Whoa, that's a close up.

I'll assume that hard line runs down to the threaded fitting on the tank? Looks like brake line.

Brian Carlson

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

I have wondered about this but never looked at it. My car being and 'oldie', 1986. It takes about an hour and a half to fill the tank. Even on the slowest setting it backs up and splashes all over the place. The entry in the tank looks smooth enough, must be the vent. Tips on proper venting or expierence in solving the same would be great.

http://www.ohiocobraclub.com
http://www.londoncobrashow.com

Brian,
That is correct. If you export the photo to a photo application you can reduce it and get the "whole" picture.

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

Hey, I was wondering what that was for on my car. Thanks Guys.

Rod
Roseville, Ca.
289 FIA #9152 "The Flintstone Cobra"

Here ya go.

http://i21.photobucket.com/albums/b2...ilsgasvent.jpg

Clay

'98 Unique #9299, 427FE side oiler (452.1-stroker), top-loader (close), 3.31 rear

Annapolis, MD

Clay, Love those little X's ;)

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

Phil, my error.........I was cleaning up my externally hosted pictures, and deleted it, duh....which killed the link. It's back......:D

Clay

'98 Unique #9299, 427FE side oiler (452.1-stroker), top-loader (close), 3.31 rear

Annapolis, MD

That's it! Thanks Clay.

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

Mine is vented like Phil's. Hose goes to a fitting in the top of the tank. I guess the EPA would have a fit over it, but it's easier than a vapor recovery system ;)

Rick, this may be why your's is backing up too. To find out, next time you gas up, just punch a hole in the top of the tank :D:D

Jim Harding
La Plata, Maryland

1982 #3004
http://www.capitalareacobraclub.com/...side.thumb.jpg

Punch a hole! I am going to have to get under there and see what is going on. I have some major trunk work planned... for some day, so I will take care of it then. A new custom tank is in line anyways.

http://www.ohiocobraclub.com
http://www.londoncobrashow.com

I noticed my tube was crempted at the top so I replaced with a new one and added a piece of gas line hose from the end back down past the frame so it wouldn't get trash in the end of tube. If you fill your gas tank all the way to cap, you may get some gas overflowing out of tube.
Bob

The 289 is harder to vent than the 427 because the filler is higher.
The tank has a 1/8" pipe thread, so you screw a fitting in for an inverted flare, (brake line size), make your own out of steel brake line and bend it to fit, don't leave it open at the top like Phil's, Unique quit doing those that way because water and debri can enter from the top. Make it as high as possible so a full tank wont let the fuel come out the vent.
You could take the steel filler tube on a 289 and modify it with a 1/8" barb fitting and run a line from the vent through the trunk to the filler tube and vent it that way.
The 427 is different because it dosn't have the steel filler tube.

Rick
#4279405

Rick,
You're on track with what we were thinking...Tap into the steel filler line, or the aluminum funnel just below the flange and vent back into the filler tube.

That 1/8" brake line looks small for the vent, especially considering the size of line running the fuel up to the engine. Have you ever had an issue with the vent starving the fuel pump or carb?

Brian Carlson

Unique 9122 - 289 FIA Cobra - The Legendary "Spence" Car

Yes, it looks small but does the job very well.

I had to drain Juan's fuel tank over the week end and it is amazing at the rate of flow after disconnecting the fuel line from the tank outlet. You could never starve the fuel system even if you had a big cubic inch bigh block with lots of HP.

Rick
#4279405

I know this is an old thread, but if your out their Brian how did you end up venting the tank?

Rod,
Brian is out of town on business, but I attached a link from his build thread that shows most of what we did. We basically used Phil's photo as a guide, but added a pig tail loop in the line to act as a trap to keep bugs and grit from getting in. What you can't see is that we took it up to the top of the wheel well and turned it back 180 degrees for about 2". It is made from 3/16 brake line tubing and works well when filling. We are running fuel injection at 45 pounds of pressure and have never had any fuel starvation issues. One problem we did have was when we were at a track day and if the tank was over half full, we had fuel come out of the vent on long hard right hand turns. This in turn softened up our undercoating which got on the wheel which threw it all over the rear underside and body. It was a real mess! We at one time considered running it back to a fitting tapped in the fuel filler casting and still may do it, but we are not sure if the venting of the fuel filler cap is enough. Let me know if you need more info or pictures.

http://www.uniquecobra.com/forums/showthread.php?t=7306

Bill

Thanks Bill, I was hoping that you had vented it through the filler and found that to work. I may have to be the guinnie pig on this one.

Rod - You said it took forever to fill tank. Mine took forever also until I disconnected the rubber hose where connected to top of gas tank and found the tank still had masking tape over hole. There was a hole about the size of a marble.
Bob

I ran a larger vent line from the 1/8" NPT fitting and added a roll-over vent valve which will close off the vent if inverted. This valve is located as high as possible under the fender well.
I also put a rubber ball under the flip top filler and safety wire it closed for track events.

I saw several cars with open vents and/or vented caps which spewed fuel all over when running on track. I've had none of these problems with my setup.