Capt Ken

Going around right corners with more than a half tank of fuel results in a fuel smell in the car. The vent valve is new, no sign of leakage around the tank. This leads me to believe it is coming from the charcol cannister. From reading those threads, I believe it is easiest just to remove the cannister and do away with the maze of vacuum lines. Is it possible to turn my non vented cap into a vented cap? If that is not possible, will a 68-69 vented cap fit on my '73 tank neck?

fishslayer143

yes a vented cap will fit

billschroeder5842

I rebuilt by canister a month ago. Not a big deal and not real expensive.

My 82 is real sensitive to vacuum and emissions--it is a CFI thing.

MajD

Interesting...I was thinking of doing the same thing. Did you replace the charcoal? If so, what did you use? Thanks.

dembo

I don't understand the logic of removing the canister to solve a fuel smell issue. It's there to store vapors instead of airing them out through a vented cap. If your car is parked inside I'd reconsider removing it. They are not that expensive.

Nick

PS my new vent valve didn't really leak but the bottom part was badly bonded which resulted in fuel smell

OldCarBum

My 73 had a bad fuel smell when sitting in the garage. I replaced everything suggested on the forum and the smell continued. I took it to a corvette specialty shop near me and they found it was the fuel sensor gasket. No more smell. As far as the fuel cap goes, I believe Stant manufactured the original fuel caps for Corvettes. They still manufacture the caps and after going to Stant's website I found the cross reference numbers for both a vented and non-vented fuel cap for my '73. I tried both on my '73 and I've noticed no fuel smells in my garage or while driving using the vented cap. When I rebuild my motor and replace the original intake and carb, I like knowing that if I choose an induction system that does not have sufficient vacuum ports to hook up the vapor canister, I now have the choice to remove it and the vacuum lines.

MelWff

since it happens only at more than half a tank it is not the fuel sender gasket, it would happen all the time if it was from the bottom of the tank. The neck of the gas tank where it connects to the tank has a cork gasket. Over the years the gasket disintegrates and will only leak when full or gas sloshes up near the top of the tank. Link below for gasket.

https://willcoxcorvette.com/corvette...k-gasket-63-74

Capt Ken

The fuel tank is new, installed 3yrs ago by the PO. I looked for leaks, see no trace, have to assume the cork gasket is ok. The vent valve is also new. I replaced it, when the Bubba epoxy fix didn't work. PO did that, so maybe I should rethink the cork gasket. But again I can see no sign of leakage. I don't have the spare tire carrier so I have good visibility of the area. I've got several vented pieces of yard equipement in the garage...A vented cap isn't going to add much to the smell. The thought about the vapor cannister is that the charcol is probably shot. I have not pulled it to inspect, but would not be surprised if it is cracked, thus any fuel or vapors that make it that far have as much chance of entering the cabin as they do being sucked into the engine. My car is a hodge podge of parts/mods so keeping it stock isn't an issue for me.

billschroeder5842

I rebuilt it and used new charcoal. I works as specs call for.

I got the charcoal from petsmart in the tropical fish section. The stuff is the same. $14

Drop your canister from the bottom of the car-- you will have a super difficult time if you try to pull it from the top

Peterbuilt

Is this what you're calling a vent valve?
It's on the top left side of the tank and it's supposed to allow fumes to pass to the vapor canister but not raw gas.

https://willcoxcorvette.com/corvette...or-valve-70-74

Capt Ken

Yes that is what I was calling the vent valve. Maybe I need to pull it and inspect, looks fine from the outside. Is there an way to check it's functionality?

Alan 71

Hi CK,
I believe the only test is to shake the vapor separator once it's removed.
If you hear what sounds like a ball bearing rattling inside the separator is good.
Regards,
Alan

Capt Ken

Filled the car up today, made a bunch of hard right turns in the neighborhood and got into the garage quickly before anything could evaporate. Fuel is leaking from one of he spot welds that hold the strap for the vapor seperator. I'll get under and clean it up tomorrow, thinking JB Weld is probably the easiest fix.

Alan 71

Hi CK,
At least now you know, and have a plan!!!
Regards,
Alan

Peterbuilt

A three-year-old tank with a leak!
They sure don't make them like they used too!
JB weld on a gas tank, that would make me a nervous wreck.
If it were me, I might pull the tank and have it professionally welded.

An experiment if you are in the mood:
About testing the vapor separator, I wonder if you might have time to connect a rubber hose to the bottom port and with a small funnel pour some gas in and see if it comes out the top port.

Capt Ken

Dug around and found the reciepts from the PO. Tank is from Ecklers, purchased in 2008. Still you would think it would last longer. No reply yet on any warrenty claim I might have. I was focusing on the Vapor seperator because I could not physically find a leak. At low fuel levels, no smell, so I think the Vapor Seperator is ok. Will still rebuild the charcol canister at some point. Other than welding, anybody else have an idea how to fix it?

Msbfdx

Welding is the only real way. Be sure the tank is purged well. I like to lightly pressurize the tank with either nitrogen or argon.

OldCarBum

If the tank was purchased in 2008 and its already leaking, I would not spend money welding the tank. I would purchase a good quality tank and ditch the old one.

BLUE1972

Run the tank level down low. Look into the tank with a mirror and flashlight. You may find that the top of the tank has corrosion due to the PO storing the car with a low level of fuel in the tank.

That is part of why Stabile has the new 360 storage stuff to protect the exposed part of the tank above the fuel level.

Glad you found it..

GUSTO14

You say it is leaking around the bracket that holds the Tank Fuel Separator Valve. This bracket is really doing little more than holding the plastic valve which for the most part should remain empty. I'm guessing that one of the spot welds holding the bracket to the tank was done poorly and is allowing fuel to leak now. If the bracket still feels securely attached to the tank, you might try just using the J.B. Weld as simply a sealer around the bracket. Or you could also pour some fiberglass resin (mixed with the requisite hardener) around the bracket to better flow around it. I sealed a tank back in the 60's that had a pin hole in it, with nothing but resin and it was still in place many years later when I replaced the tank during a restoration.

Of course that presumes that the tank is otherwise in good condition and free of rust, particularly on the inside. I would examine the inside of the tank carefully for any evidence of rust before spending any time trying to repair it.

Good luck... GUSTO