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Gas tank vent?
Posted: Tue May 22, 2007 1:58 am
by 73SpeedBuggy
Does the gas tank need vented? I installed a new tank on my buggy (purchased back in '05, been on the road for about a month now) as the old one was rusting through. The new one has a hose fitting on the neck like it wants to be vented. Does it need to be vented? It seems to me that with a hose on that fitting there, if I take a sharp left turn gas would spill out the hose.
Posted: Tue May 22, 2007 4:12 am
by 5150bossman
Two directions you can take. You can either use a vented gas cap, or you can run a couple of loops in the vent hose to prevent the gas from spilling out.
Posted: Tue May 22, 2007 4:23 am
by CairoManx
If you have a gas cap that makes a seal, then yes the tank needs to be vented. If you have a 68 or later style tank with the filler in the back, then a vent hose connected to the filler neck shouldn't get much slosh. If you have a 67 or earlier style tank with the filler in front, then yes the stock vent hose connector will probably leak when you turn and stop. That's why a lot of people weld the stock filler neck location on older tanks closed and relocate it to the top rear of the tank. Some builders use flip open type filler caps that are designed with a vent. If you just have a stock VW gas cap then you could drill a small diameter hole through the top of the cap and plug off vent line fitting on the neck with JB Weld. If the engine gets starved for gas, drill the hole bigger.
Posted: Wed May 23, 2007 12:12 am
by TMc2548
I ran into this problem when I was relocating my filler neck on my '71 tank. I ended up using the outlet pipe as a vent by drilling a small hole at the area of the original filler neck and welding it in place. It is in the top most location of the tank when installed in the buggy and is in an expansion area where there will be no gas. I'll attach a hose to it and loop it a couple of times. Being the same ID as the outlet I'm hoping for a neutral pressure when idle and running.

Posted: Wed May 23, 2007 3:15 am
by 5150bossman
I believe the old VW van gas cap is vented. Not sure which year though.
Posted: Wed May 23, 2007 12:01 pm
by 90volts
i don't have any problems with gas sloshing out. no loops in the vent line, it just runs down the side and behind the beam. i fill up to the top edge with gas as you're looking into the filler.

Posted: Wed May 23, 2007 12:04 pm
by newmanx59
The problem with venting the fuel tank is you have to run the tube under the buggy so you don't get the fuel vapors or worse yet, the raw fuel in the passenger compartment. This is how I vent the tanks.

All the fuel vapors and raw fuel exit below the buggy.