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Fuel Breather
JamesyCottony - 27/12/14 at 10:59 AM

Looking at the IVA any pipes attached to the fuel tank need to end outside in case of leaking fuel, does this mean that the fuel breather pipe has to be outside or can the breather pipe be inside? There is a one way valve on it as well.

Cheers


theprisioner - 27/12/14 at 12:34 PM

Bad English I suspect. Imagine a leak from any part of your fuel system does it end up inside or outside the car? Fuel pipes are best run outside for that reason. You can run metal pipes inside the car (mine are in an enclosed - gear selector tunnel, technically still inside the car) but I assume you still need a drain path should they leak. I drilled a couple of holes in floor pan to ensure they had a drain path. I have never been happy sharing the inside space with fuel pipes. A couple of mates of mine have them running inside the passenger space I guess it complies if either braided, Kunifer or steel.


JamesyCottony - 27/12/14 at 01:52 PM

We have copper fuel line running through the middle of the passenger compartment, so may need to drill a couple of holes for drainage.

IVA wording for fuel tank breather:

"The fuel tank must be fitted with a vent (to permit release of a pressure build up) which does not exit on to the exhaust or into the vehicle or be situated at such a height that fuel would be likely to leak when the vehicle is driven."

I am attaching an air filter to the tank breather so should I just mount this outside the vehicle?


adithorp - 27/12/14 at 02:04 PM

So currently you plan to have the fuel vent in the passenger compartment?

Don't think that will pass IVA and it'll need to be fed outside... and it'll stink the car out. Fuel vapour isn't the best thing to be breathing.
Are you using a (2way) valve on the vent pipe? Why have an air filter on the pipe?


JamesyCottony - 27/12/14 at 02:10 PM

The tank is mounted in the 'boot', which is separate to where the driver and passenger sit, so would it be safe to have the fuel breather inside this compartment or should I mount it outside?

This is the valve that we have for the breather:




I think its a 2 way.

I want to use a filter on the breather so that no rubbish can get in the tank, I know the valve stops this but I wanted to add an extra bit of safety


JamesyCottony - 27/12/14 at 02:21 PM


I found this in another thread. Can I do what this guy has done with his breather?


quote:
Originally posted by renetom
Hi
we have this & it works fine & the valve costs under a fiver.
if it goes tits up the fuel wont leak out , tested it.
we are running carbs so its all we need.

Tank breather & non return valve
Tank breather & non return valve


Good luck


adithorp - 27/12/14 at 02:29 PM

You really don't want to vent fuel vapour into an enclose space. It's highly explosive! (worse than actual fuel). It's also heavier than air so will "poo"l in the bottom of the boot.

Rather than and air filter on the end, I'd put a cheap push fit fuel filter in the line then drill a hole somewhere in the boot floor, fit a grommet and push the breather pipe through. Any vapour will then disperse safely.


JamesyCottony - 27/12/14 at 02:45 PM

Only thing is that the IVA states that it must be high enough so that fuel will not come out when driven, and if I do as you say then I fear it wont be high enough. Could I drill a hole in the side of the boot and have the filter poking out the side? (even make a little cover for it out of aluminium)



Looking from the back:



It would be situated far enough forward from brake line pipe and far enough in that it would be 2 inches away from the brakes.

Looking from the top:




[Edited on 27/12/14 by JamesyCottony]

[Edited on 27/12/14 by JamesyCottony]


JamesyCottony - 27/12/14 at 03:41 PM


theprisioner - 27/12/14 at 04:04 PM

Why so complicated, most people loop the pipe to the highest point possible then take it out to drip below the floor level to the ground.

There are issues on fuel overflow issues for using your car on a track but no need to think about that unless you are tracking it.


JamesyCottony - 27/12/14 at 04:06 PM

But with coming out the bottom to the ground surely there is the problem of the vacuum sucking up water into the tank?


jacko - 27/12/14 at 04:13 PM

If you say what type of vehicle you have it may make more sense


JamesyCottony - 27/12/14 at 04:16 PM

quote:
Originally posted by jacko
If you say what type of vehicle you have it may make more sense


Onyx Bobcat


renetom - 28/12/14 at 08:06 AM

Hi
The photo you show is our car

Tank breather & non return valve
Tank breather & non return valve


The IVA man saw it & was happy with it.
Good luck
Rene

Further to this post
As we are running Carbs all we needed was a
one way valve to let air in, therefore there
never has been any smell + we fitted 2 grills
in the back panel to reduce the parachute effect
and if there were any smells this would disperse them.

Rear Vents
Rear Vents


As long as they are not within the driver/passenger compartment that's fine.

[Edited on 28/12/14 by renetom]

[Edited on 28/12/14 by renetom]


JamesyCottony - 28/12/14 at 09:07 AM

Thanks for replying mate

Wanting to put the breather outside though due to the fumes, I just remembered there is a small hole which I could try and poke the pipe through and put a filter on the end




If I put this outside will it be ok with picking up water and bits?

[Edited on 28/12/14 by JamesyCottony]


Angel Acevedo - 28/12/14 at 02:16 PM

Why don't you use an inline fuel filter instead and a 90 º bulk connector at the end?
This way yo have a tidier exit pont and less to worry about the filter mucking up.
HTH