Easiest way to install a vent in my gas tank.

With the tank out of the vehicle, drill the filler neck, insert a short piece of 3/16 steel brake line and have it brazed in....   Flush tank before and after....   Run a rubber hose / line into the fender well and incorporate a loop into it ....   My .02

I have read that the vent tube should not be smaller than the gas line.

The tube on a stock VW tank is smaller than the gas line. It is probably for air to move through a tube than gas through a tube.

I have 2 pre 70's tanks on hand. looking down into the filler the vent tube is pinched almost flat on the end sticking into the filler neck. I would suppose that is to keep fuel from passing out the tube as it sloshes around in the tank.

Bill

Do any of you guys run a return line to your gas tank?  I saw a few threads on that and was wondering what the benefit is if you are running carbs

That's only for electronic fuel injection.

Also, I've aways run 3/8" fuel lines, and my vent tube always seems to be 1/8" - 3/16" or so ID.  Everything seems to work OK.

i'm running the vent on my car into an "S".  full tank of gas and a hard corner and i can smell gas.

isnt there a one way vent?  what was it called?? PCV valve?

Check valve-old related link:

https://www.speedsterowners.com...ent/2135445019488409

thank you sir.  i'll be stopping at a motorbike shop and see what they have.

I've had a couple of emails on this and checked my stash and I've given away those extra one-way valves that I had, so I looked them up at NAPA and here's what you can buy:

NAPA Part number CRB 21038  (it's called a vacuum delay valve, but it's just a 1-way check valve used on a whole lot of Ford engines.

An alternate part number is CRB 229269, although it has slightly different characteristics.

The local cost was $13 - your cost may vary.

Alternatively, you could wander through an auto salvage yard and look under the hood of Ford cars from the 1980's into the 2000's.  One one or more of the vacuum hoses running to the vicinity of the carb/throttle body there should be a vacuum check valve.  the one you want should be black on one side and white on the other.

When you get it, blow through it in both directions.  One way will blow easily, the other way will not.  Connect it such that you can blow easily into the tank (it's supposed to be sucking air in as the gas flows out, right?) then connect another length of tubing on the end opposite the tank and you're done (after routing the vent tube somewhere inconspicuous).

All the best!

gn

BTW:  I've never gone nuts running the vent tube anywhere in particular.  The one on Pearl goes through the bulkhead next to the tank and is fastened to the front firewall (foot kick panel) at the top, just below the cowl.  Just for the heck of it, I put a lawnmower fuel pickup screener on the end because (a.) I had an extra one kicking around and (b.) it keeps foreign stuff (think bugs, here) from getting in.

I think that the total length of the breather vent tube(s) is about 16".  It seems to be working OK because I never hear the gas cap sucking air when I remove it to fill the tank.

Also, since there's a check valve in there, I don't believe it ever "burps" to cause a raw gas smell in the garage.  The raw gas smell comes from the open float bowl vents on the carbs and there's not a whole lot to do about it (other than build a garage detached from your house like I have).

Yeah, Mango, what Gordon said. I found my check valve at NAPA and I think it was 5 0r 6 bucks.  I put a 6" loop in the tube after the filler cap and then out through the wheel well.  I still had some gas smell coming from the vented gas cap. I haven't  found an un-vented cap to replace it, so I have a zip lock bag and a rubber band over the neck (Mickey Mouse I know)but it works until I find the right cap.. I thought I would find a cap at Carlisle but no go.

Al:  Remind me of the cap just before Aug. 4'th and I'll look at the VolksVair show for ya.