Fuel Tank Vent

[Richard454]

I've decided to run the Aeromotive Phantom system to "convert my tank" w/o have to weld on it. Looks like a pretty neat design-simple to install. Just have to drill a few holes in the tank.

http://aeromotiveinc.com/products-page/stealth-fuel-systems/18688-phantom-340-stealth-fuel-system/

[ame]http://www.youtube.com/watch?v=OZrgh3QrIh8[/ame]



I am looking at what's the best way to 'vent' the tank.

The Aeromotive set-up comes w/ a AN fitting for running the vent line-But where to?

Everyone I talk to says-
"in the trunk" or "above the tank." Both which are really tough to do in an a C3.

I was looking at this- but where the heck will it fit? Nice solution- but sorta big.

Looking at putting the vent in the rear deck 'Astrovent' ducting between the tank and interior - since I am closing that off and running Vintage Air. I hopes of keeping fumes out of the interior.

Have read about using aquarium charcoal canisters to handle the fumes...Looked at a couple of vents used on marine and airplane applications...



And here's an in-line filter to take out the water-

Am I over thinking this? Thinking about minimizing problems w/ethanol crapped up gasoline.

Any ideas?

Richard

 

[mrvette]

On my '72, I have what is essentially an L98 engine, so running a fuel pump on the back frame rail, through the stock lines for supply and return, I put on a locking gas cap, it's vented, the control valve on the charcoal canister is blocked open and the vent line goes to the throttle body, above the blades.....I have the stock vent valve on the left/drivers side of the tank, ....

NOW, my tank was changed out some decades ago by previous owner, and so I finally found the smell coming from the tank, that was a mystery fitting to the left and forward of the filler cap, take the rubber rain guard off, you maybe have the same thing, I spotted it once with the tank full, it was wet outside....I cleaned it up good, and buried it in epoxy....

:beer:

 

[68/70Vette]

I was looking at the Phantom set up also!!

First of all the fuel pump location. Installing it will be easy since I have my fuel tank setting on open frame. But....consider what happens when the body in installed and then the pump fails...you have to drop the tank to replace the pump. I had a hell of a time getting the tank out of the 68...the tanks don't exactly just fall out. Plus a 70 tank has those vapor return lines to the front gas fume charcoal cannister. The vapor return lines, and the little shut off valve (shuts off possible gas flow to the charcoal cannister if the car is upside down) will all snag to make removing the tank more difficult. I'm wondering about just having a little fuel pump housing welded on the bottom of the tank so I can replace a fuel pump from the bottom of the tank.

Did you check out their recommended plumbing to the engine. If you have FI, they recommend a 3/8 inch gas line to the front regulator and a 3/8 inch regulator overflow line back to the tank. The stock 70 fuel lines are 3/8 inch to the engine (OK) and 1/4 inch overflow back to the tank (not OK).

If your going to run more than 500 hp with a carb, they recommend 1/2 inch gas line to the engine regulator and 1/2 inch (!!!!) from the regulator back to the tank. If have tentative thoughts of buying 1/2 inch CuNiFer alloy gas line to make these line myself. Running two 1/2 inch lines through the tranny crossmember is an extra complication. CuNiFer doesn't have any bling, so if I do this, I'll segment the lines and use Stainless Steel where the lines go into the engine compartment and can be seen.

Aeromotive shows a cartridge fuel line filter in their application pdf. I plan to use one of their large cannister filters for less pressure resistance and more filtering capacity.

Finally....don't understand you concern with a vent. I have an unvented gas tank cap. Doesn't the unvented cap have enough venting capability? Just add a 90 vent outlet on top of the tank if you're concerned? I wouldn't vent into the passenger compartment though. On early C3's there are draining tubes from the compartment behind the rear window to the wheel wells to drain water off the rear window and flow it outside via the wheel wells. Good place to put a tank vent also.

 

[Richard454]

I went back and forth about an external pump... ease of replacement- but the in-tank has the cooling of the fuel...

I'm running sidepipes - dropping the tank is not that much of a pain-but these days- good in-tank fuel pumps are good for over 100k.

My car is far from stock- new tank - and I am plugging the OEM vent lines. The cap is sealed. No charcoal canister. And no real plenum it run vapors to since I'm going w/ ITB's....

I'll have AN-6 for supply and return- custom fuel rails- and the regulator is mounted to the fuel rails in aluminum billet housing. I am going with a rollover valve and running a Russel billet profilter- has a replaceable filter as well.

Everyone I have spoke w/ recommends not using the cap as a vent.

Like I said- maybe I'm over-thinking this- but feel an open vent will not help much w/ the ethanol gas picking up water...

not much stock here-

Richard

 

[mrvette]

On my '72 the black plastic float valve leading to the evap canister would lock up sometimes, like when the tank was full, that float was intended to keep fuel outta that canister line, but with the EFI on there, the fuel was also increasing temps in the tank, because of the return, and so being in FLORIDA, that would put positive pressure on the tank with the OEM cap being sealed, I would get back home and wondering about that silly gas smell, pop the cap and release pressure.....the only way that pressure could build is if that valve float was pushed up with fuel, and then held by pressures building up in the tank....

so a locking/vented cap, and problem has gone away....no fumes, no smell....

Like I maybe have said, I use the stock fuel lines for feed and return, I can take the line pressure down to 35 psi with the adjustable regulator, so I know there is no issue with restriction, but I not running but about 350 hp on an almost stock L98 setup....I leave the regulator set at ~40 psi, all of this with engine off, and just running the pump alone....:gurney:

 

[Richard454]

I think I found an answer...

Run vent line from Aeromotive housing to rollover valve and then to a charcoal canister used on GM power brake lines ($10 solution part # 80195) to a vent-open air...

Actually found this on a Mustang site- to deal w/ smell & pressure when adding EFI.

 

[BBShark]

A charcoal canister on power brake lines?

 

[Richard454]

Yep- a charcoal canister for power brakes!

Here's how I ended up doing it-

The Aeromotive vent needed a roll-over valve-and they recommended the vent to be 6 inches above the tank...Sort of impossible unless I put it on my convertible top!!!

So- I capped off the vent on the Phantom piece w/ AN fitting...

Drilled a hole to fit roll over valve at the corner of the tank-ran that to my charcoal filter then using a stainless steel vent ( designed for boats ) into the rubber fitting around the gas tank cap.

Leaking gas is going to be stopped if ever am unfortunate to roll over- also wiring an inertia switch (Ford has a good one for around $25-30- eBay and Summit) to kill the pump in case of a bad impact.

The charcoal filter will eliminate the fuel smell- also went w/ Russell synthetic rubber nylon braided lines to help w/ the ethanol gas smell permeating the fuel line.


On a side note- I decided I didn't like the red and blue fittings- so I read where you can spray w/ oven cleaner -remove the anodizing and then polish them out. I ran out of oven cleaner- but it seems to work!

 

[greg75vette]

Cool solution :thumbs: You can use Drano Crystals to strip the anodized coating as well. You make a solution with warm water and soak the part. I'ts a bit fumy, so be careful and don't leave your parts in too long --unless you like black. :flash:

 

[MYBAD79]

I like that oven cleaner idea..... What did you use? "Easy Off" ?

You better use that Drano outside ... Lol.....

 

[BBShark]

I think I found an answer...

Run vent line from Aeromotive housing to rollover valve and then to a charcoal canister used on GM power brake lines ($10 solution part # 80195) to a vent-open air...

Yep- a charcoal canister for power brakes!

Now I get it, not brake LINES, brake booster

Dorman/Brake Booster Filter Part Number: 80195

 

[BBShark]

I think I found an answer...

Run vent line from Aeromotive housing to rollover valve and then to a charcoal canister used on GM power brake lines ($10 solution part # 80195) to a vent-open air...

Yep- a charcoal canister for power brakes!

Now I get it, not brake LINES, brake booster

Dorman/Brake Booster Filter Part Number: 80195

Just now getting around to doing this. I can't find any information that says the Dorman 80195 is anything more than a filter. No info that it is a charcoal canister.

Been looking at motorcycle fuel evaporator charcoal canisters and that looks like it might work (smaller, passive).

 

[BBShark]

Found a motorcycle charcoal canister for California Harley's.