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Gas Tank Vent Hoses


steve72z

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I know this subject has probably been beat to death in the past but I need some advise. I am getting ready to re-install my gas tank in my 72 240. I have heard of people eliminating the vent hoses and venting to the atmosphere via a vented cap or just letting one of the vent hoses vent to the atmoshpere.

 

Has anyone done this? how did you plug the hard lines coming out of the tank? How do you plug the nipples through the floorboard?

 

Any help would be appreciated.

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You can't just plug all the lines. I tried and I could only get 8 gallons into my tank.

 

The way to bypass the tank is to connect all the lines together, then run the one line up through the floor and to the filler neck. Then run a vented cap. I helped Matman do this on his 71. Cost a bit in fittings to get the 3/8 to 1/2 to 5/8 hose connections, but it was easy to do.

 

I think the problem of the hoses is worse for the early Z's with the plastic expansion tank. When I first put my 70 together I split 4 of those plastic tanks before I finally went to a metal tank out of a 72 (requires the later interior panel too). With the metal tank I ran the car for a long time until the hoses finally started rotting again. Now I'm going fuel cell. Screw the damn stock tank... :mad:

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I removed the tank thinking I would install a fuel cell. After researching the subject I found out the best cells to use that should meet most if not all racing specs include Fuel Safe and ATI. They cost around 750-850. I changed my mind and decided to clean up the old tank and reuse it.

 

Thanks for the info.

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when classiczcars.com comes back up, do a search over there. Someone recently posted how they eliminated the surge tank and most of the vent lines. Probably the route I will go when I redo mine, and keep the vent line to the engine compartment.

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If you decide to keep your tank and add the manifold connecting all the vent hoses, MAKE SURE to get the hose clamps extremely tight!! I have seen a puddle under the back of my car.

 

Regarding the fuel cell, do you have to lose the spare tire and tub to install it? Per your link, Jon, with the filler neck right on top, it looks like either that, and put it where the stock tank was, or raise the center of gravity and put it on the luggage deck. :dunno:

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I welded all the tank vent lines except the one on top towards the front of the car. I took out the expansion tank, and ran a hose from the top vent line of the tank to the filler neck. Then I vented the cap, or you could run a vented cap. Never have a problem filling my tank, and no vent hoses, and expansion tank to worry about.

The nipples through the floor boards, I just filled up with silicone.

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I would like to add a follow up question. Can I remove the vent line that runs from the top of the expansion tank to the charcoal cannister and then use both large diameter hard lines as fuel delivery and return lines. If yes, should I just cap off the top vent line or "Y" it into another line? Do you see any problems with fuel delivery with the larger return line?

 

Early 260z, L26, SU's with both electric and mech. fuel pumps working.

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I welded all the tank vent lines except the one on top towards the front of the car. I took out the expansion tank' date=' and ran a hose from the top vent line of the tank to the filler neck. Then I vented the cap, or you could run a vented cap. Never have a problem filling my tank, and no vent hoses, and expansion tank to worry about.

The nipples through the floor boards, I just filled up with silicone.[/quote']do you get fuel fumes when parked in a garage with a full tank? Reason I ask is that my tank is currently vented to the atmosphere, (the valve in the engine compartment isn't hooked up) and it stinks it up real good when the tank is full.

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Thank's for all the great replies. I am wanting to eliminate the vent lines because the Z has been sitting for 8-9 years and all the lines are rotted. I was planning on installing a fuel cell but $ is tight. I decided to reinstall the tank after cleaning and painting it. I have had problems with exhaust and gas fumes in the past and wanted to eliminate as many potential problems as possible. Also I was not looking forward to spending ~150.00 on the new hoses.

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Also I was not looking forward to spending ~150.00 on the new hoses.

 

I saw a post a few weeks ago where someone posted a link to a fuel line repair where they made their own hoses. But for the life of me I can't find it again. I've been searching for a few days now, and have gone through hundreds of posts.:twak:

 

That's how I found this one. I think he spent less than $50 for the whole thing. I like the Idea of keeping the stock expansion tank if I can get the lines repaired. For now I've priced out some SS braid from Summitracing @ around $125. Much cheaper than MSA's $250. And it will probably last longer. Still not sure what I'm going to do. I can't even fill the tank because the fuel would spill out of the Vent lines.

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