[RocktimusPryme]

Sometimes I dont mind the smell, but it does get old. You can tell Ive been driving my Firebird after I get out of it sometimes because my clothes smell vaguely of fuel.

So I want to make a charcoal vapor vent system, and Im soliciting opinions on how to do that effectively.

I currently have a Tanks Inc tank with an in-tank fuel pump. ( I have Terminator Stealth TBI) The vent line currently ran to a short length of hose that is held to a high point on the floorpan with a magnetic zip-tie anchor.

So here is my general plan and somebody can tell me if I have this wrong, if there is a better part I should use etc. It gets confusing because I know newer systems use a valve of some sort. Im told older systems used ported vacuum sources so it wasnt sucking all the time.

I want to buy this affordable dude here
https://www.amazon.com/Canister-%E2%...55203762&psc=1

Mount it on the firewall, run a line from the "Tank" fitting to the vent line in the tank. Run a vacuum line to the ported spark port. Fresh air comes in from the bottom of the unit, and in theory thats it.

Now tell me why it wont work.

[59safaricat]

You can give it a try but I think you may be wasting your time on it.

I had an early 70's Chrysler that came from the factory with a charcoal canister/sealed gas cap/fuel system. I didn't notice much of a difference in fuel scents between it and my 1959 Pontiac sitting in the garage independently. The carb will still emit fuel vapors.

[RocktimusPryme]

Originally Posted by 59safaricat

You can give it a try but I think you may be wasting your time on it.

I had an early 70's Chrysler that came from the factory with a charcoal canister/sealed gas cap/fuel system. I didn't notice much of a difference in fuel scents between it and my 1959 Pontiac sitting in the garage independently. The carb will still emit fuel vapors.

I dont have a carburetor.

And honestly my Firebird is notably worse than my other old cars. Maybe becuase the vent tube in my tank is 3/8 instead of a little 1/4" vent.

And I might be, which is why I want to do it reasonably cheap. but for $50-60 in parts Im willing to take a swing.

[Mister Pontiac]

One other thought, Rocktimus...

My 74 Bonne has the canister and full setup you're describing, and it does not smell near as bad as all my other Pontiac's.

But the other thing it has is an inlet hose to the air filter assembly, that ducts to the core support for fresh (not underhood) air for the intake. The opening is below the level of the charcoal canister.

Now I'm not 100% sure, but seems to me those vapors are lighter than air as the vacuum port for my canister is at the top/back of the carburetor. So as the fuel vape's off after shutdown, it may be that the vapors are settling into the air filter assembly, but not working their way down and out of the inlet hose thru the core support.

If you're running an open element air cleaner, you may be smelling it thru the filter element as the odors vent out of the carb after shutdown.

Just a thought.

[RocktimusPryme]

The open air filter part of the equation is an interesting point. I hadn’t considered that an open element may make the smell worse.

And I think that one I linked has an air port on the top too. I’m not 100% what the holes on the bottom are for. It has that third port on top though.

Maybe I’ll get a factory style drop base snorkel for street driving and put the open filter on when I go to the track

[OG68]

Vapor recovery was designed to capture fuel vapor from the float bowl and the tank.
The factory canister retains the fumes when the engine is off. They get sucked into the carb/air filter or PVC by engine vacuum.
If you're having fuel smell while driving, that may be a different problem.

To successfully retrofit you may also need the vapor/fuel separator mounted to the back seat frame or a fuel tank with the vapor chamber on top.
70 and after Service Manual has a good operational description. Chapter 6D

Photos from my 70 El Camino with the factory open air filter.

[Scarebird]

I simply ran the vent tube line from the fuel/vapor separator to the charcoal cannister, then into the airbox.

This is with fuel injection.

[RocktimusPryme]

Originally Posted by Scarebird

I simply ran the vent tube line from the fuel/vapor separator to the charcoal cannister, then into the airbox.

This is with fuel injection.

So I guess my missing piece of the pizzle here is I dont have a fuel vapor separator.

When I put fuel vapor separator into Google I keep getting items like this Mopar unit. Which looks to me like a fuel filter with a separator built in, which I dont think would work like we are intending for my setup. Especially because my fuel lines are a combination of 1/2 steel and -8 AN lines.

My original plan was to just have this circuit only on the vent line for the tank, not crossing over to my actual fuel lines.

https://www.yearone.com/Product/chrysler-b-body/x868

[ID67goat]

Just some feedback…….After installing basically the same setup as you (Sniper, tanks inc, etc) I basically have no fuel smell in my garage anymore. Are you sure there is not a small leak somewhere or some other issue?

[RocktimusPryme]

Originally Posted by ID67goat

Just some feedback…….After installing basically the same setup as you (Sniper, tanks inc, etc) I basically have no fuel smell in my garage anymore. Are you sure there is not a small leak somewhere or some other issue?

99%, I have looked forever because I also feel like my fuel economy is not quite what it should be. I have never been able to locate any fuel leak. I wont swear it on my life or anything, but I have looked my butt off for a couple of years now and never found anything.

How do you have the vent port routed in your set-up? Because again, mine is pretty much just an open tube routed a little higher so it doesnt leak when the tank is full. Thats another reason I sorta want to try this. If nothing else, it will be an improvement over my current redneck vent setup.

FWIW, its not so much that my garage smells, or if it does Im just used to it and dont notice it. This is mostly a when Im driving it situation.

[OG68]

Perhaps fuel is sloshing out of your vent hose when hard braking / accelerating.
Ames has a vent hose with a filter that may restrict fuel slosh

https://www.amesperf.com/parts/36579/

[Formulajones]

Just a tip on those vent hoses, when running them off of a Tanks Inc tank for example, the line really should be coiled 4-5 times and then the vent mechanism mounted on the end of it. It can be as simple as using about 5 feet of hose, run it up from the tank as high as you can, and then coil it above the rearend somewhere and secure it.

Running a straight line from the tank up above the rearend (typically highest point) usually won't be enough as fuel will still slosh up there.

[RocktimusPryme]

Originally Posted by Formulajones

Just a tip on those vent hoses, when running them off of a Tanks Inc tank for example, the line really should be coiled 4-5 times and then the vent mechanism mounted on the end of it. It can be as simple as using about 5 feet of hose, run it up from the tank as high as you can, and then coil it above the rearend somewhere and secure it.

Running a straight line from the tank up above the rearend (typically highest point) usually won't be enough as fuel will still slosh up there.

Yeah on the first gen I do not think I am getting it above the filler neck even using the highest point I can on the floor. I do like the idea of the coiled line. But Im not sure how much the coiled line would help if the end termination is still not above the filler neck. WHich is why I had sort of resigned myself to needing to run something up to the firewall so I could get it higher, and at that point I may as well run a positively ventilated can. So it was sort of a cascade effect.

I looked at putting a vent on a line in the wheel well so I could get it higher, but it just gives me the heebie jeebies having it that close to a spinning tire.

100% honestly my very first though, was to buy a charcoal can and just mount it back there where I have the vent line now thinking it might help some even if there was no positive suction from vacuum. Maybe I will still try that with your coiled line suggestion and see what happens. Worst case it makes no difference and I end up needing to move it foward.

[Formulabruce]

Couple points on this.
1. GM used a " restricted " line under the core support coming from the tank to the canister. It required a lot of pressure and some indirect vacuum to get vapor moving ( 1971 and up) to the carb.
2. Alcohol in fuel and greater evaporation can complicate this system. It is made to be used in a " closed vent system"
This means No breather in the valve cover, and No Edlebrock air cleaners.
3. Evaporation during heat soak will cause a smell.
Good luck! The premise is good, should help some at least

[ID67goat]

Originally Posted by RocktimusPryme

99%, I have looked forever because I also feel like my fuel economy is not quite what it should be. I have never been able to locate any fuel leak. I wont swear it on my life or anything, but I have looked my butt off for a couple of years now and never found anything.

How do you have the vent port routed in your set-up? Because again, mine is pretty much just an open tube routed a little higher so it doesnt leak when the tank is full. Thats another reason I sorta want to try this. If nothing else, it will be an improvement over my current redneck vent setup.

FWIW, its not so much that my garage smells, or if it does Im just used to it and dont notice it. This is mostly a when Im driving it situation.

I have the tank vented similar to what FormulaJones had mentioned but with with 1 loop in the hose and the check valve from Tanks Inc mounted on the crossmember up above the rear end.

I am starting to think that maybe it is more of a tuning issue…or maybe an exhaust leak causing too rich of a mixture?

Could also be the nature of the beast of running a car with no cats. Years ago when I had a Foxbody Mustang it would also make your clothes smell after installing an off-road H-pipe even though the rest of the fuel injection etc, camshaft, etc. were stock…while no cats sounded and performed better, it smelled a lot worse.

[RocktimusPryme]

I can see how you might think that but I’m pretty confident I’m in the good zone there. When I first put the Terminator X on I had some issues. So I really went over it with the fine tooth comb on the exhaust/vacuum leak front. And I doubt the EFI is letting it be super out of wack on the tune.

I do have a check valve in mine too. I had forgotten about that.

[george kujanski]

Fuel vapors are heavier than air and tend to hang around about 18" above the ground, like around the fuel pumps at filling stations.

George

[VCho455]

It looks to me that what you're planning should work. Although personally I would source the canister from someplace like NAPA as you really don't have any guarantee as to what is actually inside something from Amazon or Ebay.

Since virtually every gasoline vehicle since the 70's has a canister I would hit the wrecking yard and find one to hook up as a test to see if it cures your issue.

You might not even have to hook up the purge line for a short test period.

It might of been mentioned but are you running a non-vented fuel cap?

That Mopar anti fuel slosh unit looks slick unless it's the size of a quart Mason jar. 71-72 Chevy pick ups didn't have a specific unit they just ran the vent line to the canister up inside the B-pillar to about the middle of the rear window. (First picture) Whereas on Suburbans and Blazers they installed a anti slosh unit. (Second picture)

On second gen f-bodies there is a metal canister attached to the divider between the trunk and rear seat that is the anti slosh unit. It's also found on most 70's GM big cars.

I say try it and please share your findings so we all learn more.

[Scarebird]

The EROD LS3 I installed in my Trans Am had one:

https://www.chevrolet.com/content/da...uide-Sheet.pdf

Part number 17113332

Chevrolet Suburban Chevy Avalanche GMC Yukon XL Hummer H2 Cadillac Escalade 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Evap Charcoal Canister 6.2 6.0 5.3L

[VCho455]

That canister has dimensions 6.70 in × 13.10 in × 11.80 in. Not small for sure. Where did you hide it?