gas tank vent tubes

[landon1]

what are the 4 vents (?) for on the driver's side of the tank? i do not have a charcoal canister under hood, no return line that i can find... i have one line that runs up to the engine compartment, turns into hose, runs into fuel pump, out into filter, then up to carb.

when i replaced the tank years ago, i just reconnected the 4 rubber hoses that were on the original tank. they run up into an area between the trunk and wheelhouse...don't know after that. the only reason i'm asking is that i'm trying to find a way to run a vapor separator style fuel filter and run a vapor return line back to the tank.

having some trouble with vapor lock, i think. already have a 1" carb spacer and was considering an aluminum heat shield to add to that. i've also considered switching to an electric fuel pump, but not sure that that would solve my problems either.

[471Magnum]

There should be a vapor separator canister in the driver side wheel well. Four lines go into it, plus a fifth that, depending on year, either goes to the VC breather, or charcoal canister.

The line that goes to the breather or canister, actually maintains negative pressure to keep any fuel evaporation fumes from venting into the environment.

If you want a return line, you actually need a third line running to the engine bay. 71 440 cars have three lines: the fuel line, the vapor line, and the return line.

[landon1]

okay....took a closer look. the 4 hoses go up into the rear of the drivers rear wheelwell to some kind of block (canister?), then has a 5th hose come out and connect to a hard line. where does this line go to would be my next question i guess, since i don't have any lines that go to the VC or breather. i'll have to investigate more when the car's not sitting in the parking lot.

car was originally 318, swapped to 440 many decades ago.

[471Magnum]

The canister in the wheel well is a vapor separator. Note that these are rust traps. Pretty good chance the guts are rusted.

The hard line runs over to the fuel line and then runs parallel up to the engine bay. It pokes out at rear passenger side of the engine bay. From there, a hose runs to the breather.

In 72, this would run to the charcoal canister.

As I stated previously, a 440 would have a third line, which connects to the return port on the filter and runs parallel to the fuel line back to the pic-up/sending unit at the tank.

[quapman]

If you haven't already, block off the heat crossover in your intake gasket. There's a gasket available now that's pre-blocked, but I don't have the part # handy.

[landon1]

i'm not sure if this would work...maybe someone could give me a yay or nay...

what if i used a vapor-return "chevy" type fuel filter. ran the vapor line back to the tank and had it utilize one of the vent tubes that previously went to the vapor separator. cap-off the other 3 vent tubes and use a vented gas cap??? probably not the most environmentally friendly way to do it, but would it work? right now the line that's supposed to go to a charcoal canister and into the vc/breather just dead-ends, so i don't see how this would be any worse...

i'm not sure if this is a good way to go about it or not, just an idea.

really not sure that i have a vapor lock problem - that was my initial idea, but my car just died while idling the other day, so i hurried and popped the hood fast to find my carb over-flowing, flooding the motor, giving me the hard-start issues after the car had been warmed-up and turned off, or even just while trying to drive/idle. part of my running/timing issue was that 89 wasn't good enough fuel even with a pretty mild build, so i'm running 91 now with no pinging, thus more advance = better performance.