Vented or Non Gas Cap
 

Which would be correct for my '63. The reason I'm asking is that mine has a vented cap. My wife is b*t*hing about the "gas smell" in the garage and the car has no leaks. I kind of like the smell of gas :) Could the cap have anything to do with it.

Mike

I'm not that familiar with 63s but I would guess that they did not originally come with a vented cap. On my 65 and 66 Big Cars there is a vent nipple on the filler neck close to the filler cap. Tubing is attached to this nipple and the tubing snakes/bends around such that it will vent the gas tank put not allow fluid gas to escape. I recall that the tubing passes thru the trunk just behind the trunk lock mechanism. The filler caps are non-vented on my cars. Perhaps a previous owner put on the vented cap. If you have such a nipple on your filler neck and it does not have the tubing then you will certainly smell gas. By the way that is a VERY nice 63 you have.

I battled this problem for a long time. On my 65, the factory fuel tank vent line system (just like 66bonne described it) always spilled gas under hard acceleration, or if tank was above half full, or if was a hot day, etc. So I tried closing that vent line off and using a vented gas cap. They did not fit tight enough and also spilled fuel. So I went back to a non-vented cap and tried extending the length of the factory vent line...still no luck.

Final solution (so far) was to use tight fitting, non-vented cap, closed off factory fuel tank vent line, dropped gas tank and added an entirely new vent line from the fuel level sending unit assembly, which then runs up into the area above rear axle so it is higher than fuel tank, then follows frame to jsut short of rear bumper where it is then open to the atmosphere.

I recently spllced a large metal fuel filter into this vent line, mounted vertically, to filter any incoming air, but more importantly it acts as an "exchange point" for gasoline vapors to bypass any liquid fuel trying to escape up the vent line. So far it seems to have worked, but I try not to fill the tank above half...and can't afford to anyway!

AROHED, I like the fuel filter idea; it's similar to the automatic tranny vent canister on '62s.

So, is your liquid-blocking filter mounted up in the rear "axle well" (for lack of a better term)?

63, your car needs the vented cap.
Are you sure the o-ring at the gas filler tube to the tank isn't leaking?
Did you block off the intake heat? That heat will help cook the fuel in the carb on a hot engine and make that engine more ping sensitive.

FWIW they all smell after a good drive.

What he said
 

Check the o-ring on the filler pipe to tank connection.

I used an o-ring from a foregn car water outlet for my 64 GP.

Take care,
Greg

A pic is worth 1000 words...
 

Matt..here's a pic. The blue hoses are fuel delivery and return lines. Note the Mallory 140 pump and Summit replaceable element fuel filter in background. The inline filter is on my new vent line, and it is the standard part for a mid-90's Chevy pickup. Standard flared brass fittings work great with it.

The vent line extends above the filter to the uppermost area above rear axle, then drops to follow driver's side frame rail to a nipple attached to frame just a few inches short of rear bumper....if I do get any liquid fuel out the vent line now, it at least does not end up all over rear bumper and license plate, but just drips on the ground. So far I have not seen or smelled gas since I installed this filter.
Yes, I know I shouldn't have copper tubing in there...I will be replacing it with aluminum.

I looked in my manual and it does say that all used a vented cap except the Safari. The "O" ring is fine and ithink you guys are right that the smell is pretty normal after a drive. It does fade away after a couple days.

MIke