Gas vent and fumes

[chopthebass]

I see the gas tank has a vent tube. Does this mean there will be lots of gas fumes in the garage? Is there a risk when my heater turns on? Hope not!

[wallace18]

I always run it through a charcoal canister.

[edwardb]

Yes, the tank is vented. You'll have an interesting time filling it and drawing fuel to your engine without it. I used a regular Mustang charcoal filter on my first build, and then a DIY version on the second. Never had a whiff of fuel smell from either. The DIY version is cheaper and easier IMO, so will be doing one again for the current build.

This post in my last build thread describes the homemade one, inspired by a write-up from Jeff Kleiner. http://thefactoryfiveforum.com/showthread.php?8296-Mk4-7750-Build-Progress-Update&p=179547&viewfull=1#post179547

[walt mckenna]

The gas tank from my 04 Mach 1 donor had a vent associated with the evap canister and another that terminated near the fill neck to allow displaced air to escape when filling the tank with gas. I had the evap canister purge feature disabled in my ECU, so I blocked off the vent associated with cannister and plugged the port in the intake manifold. I was also worried about fumes in the garage, but it has been two years now with no fuel delivery or tank problems and no fumes.

[2bking]

The vent fitting that came with mine had a one way valve that allowed air in but not out. I installed a small fuel filter on the end of the vent hose to filter the air entering the tank.

[Avalanche325]

The vent fitting that came with mine had a one way valve that allowed air in but not out. I installed a small fuel filter on the end of the vent hose to filter the air entering the tank.

That valve is for rollover protection, It is not sealed unless the car is upside down. However, I did the same as you. I put a small filter on it. No smell. Fuel tanks were just vented until the 70s.

[JIMOCO]

I made my own using a prescription bottle from my pharmacy. I drilled a hole in the bottom. Inserted a lamp nipple with a washer and nut on each side and a little permatex under the washer. I cut a piece of aquarium charcoal foam for the bottom, filled the bottle with charcoal and put more foam on top. Drilled a few small holes in the cap. I now have a filter that is easy to maintain and has eliminated any smell. I did the same for the rear end vent.

[chopthebass]

Sweet. I feel another fabrication project coming on!

[tirod]

While it would take a lot of air movement to force fumes out of the tank, the gas hoses have now become the larger culprit in fumes getting into the garage. Use of the old spec gas hose, even in the shorter runs near the tank and fuel metering devices, can allow up to a gallon a month to percolate thru the hose into the air.

Use modern hose with the teflonized interior and it's no longer a problem. Most auto parts sources are switching to the newer hose as a result of the change in SAE specs. It become important because modern gas with alcohol and up to 50 different additives in region specific formulas is now the rule. Aircraft and racers have already moved to teflonized Kevlar armored hose over the last ten years, especially for high pressure EFI systems.

Venting the tank is necessary, how you trap the fumes up to you. In an enclosed, attached space under your household roofline, it would be better to control what fumes there are and minimize them. Garage fires are a quick way to lose a house as too much residential construction fails to isolate them from flames spreading under the roof. Those car fires start from using obsolete hose that rapidly deteriorates in contact with modern fuel.

If you are using rubber based fuel lines that extend from tank to carb made from some unknown material and smell gas in the garage every time you enter you have a serious fire hazard. The Cobra will be the least of your problems at 2AM. Don't set yourself up for failure. Use modern teflonized hose and minimize the amount of it's installation - exactly the same as the manufacturers do on the daily driver parked next to the Roadster.

[2bking]

That valve is for rollover protection, It is not sealed unless the car is upside down. However, I did the same as you. I put a small filter on it. No smell. Fuel tanks were just vented until the 70s.
I learn something everyday. When I blew through it and found it to be a one way passage, I must have had it upside down.


I made my own using a prescription bottle from my pharmacy. I drilled a hole in the bottom. Inserted a lamp nipple with a washer and nut on each side and a little permatex under the washer. I cut a piece of aquarium charcoal foam for the bottom, filled the bottle with charcoal and put more foam on top. Drilled a few small holes in the cap. I now have a filter that is easy to maintain and has eliminated any smell. I did the same for the rear end vent.
I like the prescription bottle idea and will replace the filter I currently have on the end of the vent tube.

[cgundermann]

I made one out of a PCV tube and capped it on both ends - with an in & out fitting. Used aquarium charcoal in a small bag of panty hose inside the tube.

[BEAR-AvHistory]

Took a different approach than the prescription bottle. Short length of PVC pipe with end caps drilled to accept hose barbs & filled with a bag of fish tank filter charcoal.

EDIT: above was posted while I was typing DUH. Same as the picture but unpainted.:D

[cgundermann]

Can't tell you how effective it is yet, since I am close to first start. Just know my bride is hypersensitive to fumes - so I added insurance...

[chopthebass]

I made one out of a PCV tube and capped it on both ends - with an in & out fitting. Used aquarium charcoal in a small bag of panty hose inside the tube.

Nice. Are your end caps removable so you can replace charcoal?

[redfogo]

I dont plan to use on on my 818, but another car I owned for 7years I ran no charcoal canister and just had a open line vented out. I never had any sort of smell in the garage or while driving. Car smelled the same with and without the canister.

[cgundermann]

Yes, the vented open air side. The side the vent tube is plumbed into is glued closed with good-old PVC glue...

[BEAR-AvHistory]

Can't tell you how effective it is yet, since I am close to first start. Just know my bride is hypersensitive to fumes - so I added insurance...

Its a very effective system. Zero smell since go cart in 2014

[chopthebass]

Yes, the vented open air side. The side the vent tube is plumbed into is glued closed with good-old PVC glue...

Just been to Home Depot and got materials to make one identical to yours! Couldn't find those neat straps though.

[cgundermann]

They are a lot longer and I cut most of the mounting brackets off. I got them at Home Depot and each of the holes are used for various mounting locations for the PVC pipe. If I recall they are in with the PVC material. Also used rubber shoulder washers through the aluminum for a little standoff and dampening.