Hot Rods how to vent fuel tank?

I set a new fuel system on my F-1 with an aluminum tank from Speedway. (It mounts between the frame rails behind the differential.) All AN connections and aluminum 3/8" fuel line from the tank to the carb on my 340. No more hose clamps and rubber fuel lines!!!!

I installed a roll-over valve and a hose that goes level over past the edge of the bed, then as high as I could up under the back of the fender. There I did an upside down "U" and down for about 3" to prevent water or dirt going straight into it.

My problem is the fuel smell in my garage as the tank breathes. I've just built a brand new insulated and air tight shop for the truck, and I need a different system.

What is the best vent system for no fuel smell in the garage?

 

get a charcoal canister from a 1970s car and hook it up to the vent, and engine vacuum.

 

a vented tank shouldn't make a bad fuel smell in shop.I keep 3 cars in my shop no fuel smell from tanks. I have had a couple cars in my shop with complaints of bad fuel smell . in all cases I ended up finding some kind of fuel leak, fixed the leak ,smell gone.

 

An old thread here showed a small Dodge charcoal filter 1-68039537AA

 

Appreciate the responses! I keep checking for small leaks as that's what I suspected, but have not found any yet. As I said all AN connections, etc., all new. But will check it over again and if I can't detect any I can consider the charcoal canister.

Other than running fingers over the connections, and trying to smell any leaks, is there any other good way to detect a leak?

 

You might want to reroute your vent line to not have a dip, if fuel gets trapped in there it may cause the smell also it will not vent properly. Are your exhaust pipes close to the tank, heated fuel in the tank causes odors too.

 

post pics - had a similar problem from not having vent tube high enough and some fuel would siphon out - try running a temporary rubber hose up above rearend center

 

If you get an old canister, you can rebuild it using charcoal from Walmart, they use it for their fish tanks (aquarium) in pet supplies.

 

Thanks, Guys. I don't have a dip as it runs straight across from the tip-over valve, and it goes to the top of the rear fender so it's way above tank level. And exhaust exits ahead of the rear wheel so no problem there.

I ran SCCA autocross in the truck last fall, still had the old tank, so didn't get to test this one fully. (I have a Volare front end with 12:1 steering ratio, 1-1/4" front sway, 1" rear, and Chevy truck arm rear suspension with coil-overs.) Gave me a whole new respect for autocross guys, but man, running the cones full out in 2nd is a blast!!! Still like the HAMB drags the best!!

I'll jack it, crawl under and inspect closely for leaks today. Let you know if I find any.

 

One way to check for leaks at your connections is to wrap tissue paper around the fitting....it will absorb any leaks much better than your fingers...
Hope you find the problem.

 

As a test,try driving the vehicle without the roll over valve. [I'm not sure why you have it] Or install the roll over valve at the end of the vent pipe.

 

I don't intend to roll it over, but the valve worked as a 90* to run the vent tube horizontal before it went up into the fender area. I'll try the tissue paper.

 

C'mon guys. You are not stupid.
At least I don't think you are.

The roll over valve is a safety feature to prevent you from being drowned in fuel and burned alive when you are trapped in a rolled over car.

No one ever sets out intending to roll their car.

 

you're not helping with his problem.
Is the roll over vent valve lower than the fill neck? If so,it should be higher.

 

Don't think you need a 3/8 vent, my roadster (350 Chev) came that way, same problem. Plumbed w/ areoquip lines. My fix was a 3/8 dia. alum piece, 1" long, drilled a 1/8 dia hole thru , put in end of hose, clamped it, problem solved for me. The vent line needs to be above top of tank, added check valve at tank.

 

All the posters have made some good suggestions, including you, even if you didn't know the purpose of a roll over valve.
The charcoal canister and having the vent line high enough is probably the best solution.

 

Hey my 32 didn't have any fumes for years changed nothing , "No Leaks " and it no smells like an oil refinery in the heart of Texas ! I'm thinking gasoline makeup is different , and evaporating so easily now causing the "Smell ". I have looked numerous times , "No Leaks" ! My car is flamed , really need to watch smokin around it now or Flames will look authentic as hell will look !

 

I had wondered about plugging the 3/8" and drilling a hole more the size of what the old vented caps had. Still not seeing any leaks. May try the smaller hole, if that doesn't do it I'll consider a charcoal canister. I do have the hose routed correctly, check valve in the top of the tank, hose end at least a foot above.

 

They don't install roll bars to hang their jackets on...

 

rollover valve should be installed at tank , vent line should be 1/4" , and have atleast two large 3" loops in it the loops helps prevent the vapors from coming out as they are heavy and settle in the bottom of it . you can install a electric valve in the vapor line that opens when the ignition is keyed on ( did this for one car ) its a tank switching valve from a chevy 78 k 20 truck it has no vent option as its non emissions ( exempt for time ) also have done vapor canisters from late model vehicles as they are smaller and cheaper new . 4th gen impala works good .

 

I use it to keep from having to haul anklebiters around

 

I'll start with this tomorrow, the loops and a smaller vent outlet. See if that does it, if not, will add a canister. Thanks for the tip on the Impala one.

 

also you can use a Benz fuel tank vent valve #W0133-1788362-OES they are about $30 they go at the end of the vapor line they use these on there diesel cars

I thought I posted this last night , gues I didn't

 

A company called II Much Fabrication makes a vent that will stop fuel smells. It's expensive, but it works a treat (I have no connection to the company).

https://www.iimuch.com/products/fuelvent2

 

I added 3-4" loops today, and plugged the 3/8" hose with a brass plug drilled out to 1/8" or so. If this doesn't work, I'll move to the next step. I appreciate the tips. Will look into the M Benz unit.

 

The loops and smaller hole seem to have taken care of the problem. Thanks, Guys!!!!!!!!

 

glad to hear it s working ( I just Jinxed it )

 

Had the same problem turned out to be a steel braided fuel line seeping. Found it by air pressure in a bucket of water'

 

About 60 years ago, when I was dirt track racing, we had a requirement at our local track that the vent had to do the "upside down U" you're talking about and then go back down at least 3 inches below the bottom of the tank. The idea was that if you got upside down, you weren't going to spill fuel. Don't know if it was really effective, but I don't recall anyone getting upside down and catching on fire. Probably not the answer you wanted.

 

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If you are using our remote rollover vent valve # VVR make sure that the vent is mounted vertically. Mounting the vent at an angle may cause the vent to shut off.



If you are using our in-line remote rollover vent valve # VVR-IL make sure that the vent is mounted vertically with the check ball in the bottom fitting. Mounting the vent at an angle may cause the vent to shut off.