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Thread: Fuel Filler Pipe, Overflow Return and Breather Pipes

  1. #1
    ***Euro-Nova Supporter*** BlueNova's Avatar
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    Fuel Filler Pipe, Overflow Return and Breather Pipes

    Hi all,

    I've been trying to order new pipes, etc, so that I can fit my new VW Beetle fuel tank to my Nova. This might be an issue for others so I've set up this new thread in the Fuel Section of the Forum to make it easier to find in future.

    My main problem is how do I link the overflow return hose to the filler tube because on the original Beetle the connection is made to the metal surround which the filler cap screws into and of course I don't have that on the Nova because I've got a chrome Aston style filler cap which is located on the top of the rear wing. Here's a couple of photos from the internet to illustrate what I'm talking about ....





    .... and here's the point I'm trying to connect the overflow pipe to



    I've checked to see what the set up was on my old tank and have found that the overflow was blanked off and the small breather at the opposite side of the tank was crimped flat!! .... so now I understand why the tank had to be filled slowly!

    Anyway, I'd just like to find out if others have managed to fit a Beetle tank along with all the overflow and breather pipes, and in particular, how did you connect the overflow to the filler?

    Equally, if you've sealed off the overflow and the breather, is your tank difficult to fill? Come to think of it, do you have vacuum problems as the level of the fuel drops?

    Many thanks in advance
    Alistair

  2. #2
    Senior Member Phill's Avatar
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    Good question Alistair.

    I remember having this discussion when I built my car. I ended up buying a vent valve to vent the tank out onto the top deck using a valve designed for boats. The system works, but I often wonder if this causes fuel evaporation whereas a sealed system as VW originally designed for the Beetle must be a better solution as it re-cycles the evaporated fuel back to the tank. You can read the discussion here:- Phill's Nova Project finally begins - Page 48 (euro-nova.co.uk)
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  3. #3
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    For what it's worth... I blocked those off.
    Thanks,

    Nic.
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  4. #4
    ***Euro-Nova Supporter*** BlueNova's Avatar
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    Quote Originally Posted by Phill View Post
    Good question Alistair.

    I remember having this discussion when I built my car. I ended up buying a vent valve to vent the tank out onto the top deck using a valve designed for boats. The system works, but I often wonder if this causes fuel evaporation whereas a sealed system as VW originally designed for the Beetle must be a better solution as it re-cycles the evaporated fuel back to the tank. You can read the discussion here:- Phill's Nova Project finally begins - Page 48 (euro-nova.co.uk)
    That’s a really helpful discussion on your thread Phill ... many thanks!

  5. #5
    ***Euro-Nova Supporter*** Peter's Avatar
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    I have an 'aero' style filler, just soldered a small tube to the filler neck for a breather tube, the return pipe I just crimped closed.
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  6. #6
    Senior Member Phill's Avatar
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    After meeting up with Alistair at the weekend he pointed out to me something I had overlooked which was that the VW fuel tank has a small vent pipe on the LHS opposite the filler and overflow lines on the RHS. My Solution had been to pipe the overflow out onto the rear deck using a vent pipe designed for boats

    IMG_0388[1].jpg

    This solution allows the tank to vent during filling but does not solve the problem of vapour escaping and slow fuel evaporation. Furthermore, the small vent line that I had overlooked was also open to atmosphere allowing further evaporation. These two factors explains the tendency for fuel vapour to be detected in the cabin whilst driving.

    I therefore decided to take Laurens original advice (and one which Alistair was following and had advised me about) which is to introduce a one way valve at the small vent pipe. This allows air into the tank but prevents vapour evaporating out.

    IMG_0390[1].jpg

    Finally - to prevent the overflow vent from allowing vapour to escape I fitted a snug fitting cap over the vent to effectively seal the tank at all apart from when I fill up with fuel

    IMG_0393[1].jpg

    Now I can simply remove the cap when I'm filling up and refit it afterwards to maintain a sealed system. I'm hoping this solution will work to prevent fumes entering the cabin but also allow the tank to vent when required.

    There's an old saying, you don't know what you don't know. If I hadn't had this conversation with Alistair I would have continued as before. However, this small and inexpensive modification should solve the issue I had with petrol fumes and perhaps even save fuel?

    I'll report back later once I've lived with it for a while.
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