Extending fuel pipe z3

[ericholm]

I have been thinking about what I am doing with the extended fuel pipe, and about the comment regarding sealing everything well so no leaks occur. I am suspicious of the small pipe at the top of the existing z3 fuel pipe assembly just inside the body of the car on the top side of the plastic pipe, is this a breather pipe or overflow pipe like on a sink? If so then extending the pipe and then filling the tank to max will breach this small pipe and fuel will pour out? Of course i could always only fill to 3/4 tank to be safe, but that's not the point.

If this small pipe is not anything to worry about then no problem.....

[gas guzzler]

I don't know the answer to this and have been waiting for someone to reply as I left mine where it was. You could extend that as well though.

Andy

[Roadster]

The vent pipe is as high as the top of the tank.
You are increasing the height of the filler pipe, you don't tend to store fuel in the filler pipe.

If you do fuel will overflow out of the vent

[ericholm]

Originally Posted by Roadster

The vent pipe is as high as the top of the tank.
You are increasing the height of the filler pipe, you don't tend to store fuel in the filler pipe.

If you do fuel will overflow out of the vent

Then It that case I will cut and fill the vent pipe as the filler cap is going on the wing and if I fill up to the nozzle the fuel will be higher than the vent pipe.

Any confirmation from anyone would be useful.....thanks.

[Roadster]

Originally Posted by ericholm

Then It that case I will cut and fill the vent pipe as the filler cap is going on the wing and if I fill up to the nozzle the fuel will be higher than the vent pipe.

Any confirmation from anyone would be useful.....thanks.

In that case I would attach a rubber pipe and take the vent higher.
If you block the vent you may have difficulty - I have seen tanks change shape - a vacuum can form inside unless there is a vented cap or vent pipe

[ericholm]

Originally Posted by Roadster

In that case I would attach a rubber pipe and take the vent higher.
If you block the vent you may have difficulty - I have seen tanks change shape - a vacuum can form inside unless there is a vented cap or vent pipe

Right so in that case it looks like I will need to do the following?

fuel by eric holm, on Flickr

[Roadster]

yeah looks like you have it sorted

[ericholm]

Slight hiccup looks like I have 2 pipes a white one and a blue one?
DSCN3987 by eric holm, on Flickr
DSCN3989 by eric holm, on Flickr

[ericholm]

So yesterday I spoke to a few people about these smaller pipes and the consensus was that the white one is an overflow pipe and the blue one is a breather pipe that goes to the front engine bay where there is a small air filter.

Both white and blue pipe fixings where cut away from fuel pipe with a hacksaw blade.

The white hole on fuel pipe was filled and the White pipe was capped off.

The blue one, hole was filled on the fuel pipe the blue pipe will be capped however it has a loop that I will cut and add a t-piece to tap into it and extend it, with a 9.5mm fuel pipe from halfords and then add an elbow connector to attach it into the new Aston cap assembly making sure the new breather hole is on the top side of the assembly, above any fuel nozzle that gets put into it.

Anyhow that's the plan, so I will end up with no overflow but a tank that breathes still.

[Very Andy]

Hi Eric,
'Scuse my ignorance as I've not seen the set-up, but cant you just leave the pipes as is? The overflow pipe will ensure you don't over-fill the tank and the breather pipe is still doing it's job, albeit lower down than the Aston cap.
Is it not just a matter of fitting an extension pipe or are these other pipes getting in the way of that?

Andy

[ericholm]

Its a good point you make but when filling you would have to know when to stop as nozzle is much higher in extension than vent and overflow. if you filled to the cut off point on the petrol station pump nozzle the overflow and vent would be breached. If I just blocked them off there would be no vent and possible vacuum problems forming in the tank from full to empty scenario. Thats what I want to avoid.