Hey all,

Just after some opinions on breather hoses for fuel tanks. I've got a 1200 sedan that I use for supersprint/hillclimbs and have had some issues with fuel leaking out the breather.
The breather setup that was on the car when I got it was totally incapable of stopping fuel sloshing out of the tank under hard cornering. So I ran a fuel hose from the fitting on top of the tank all the way up the passenger side 'c' pillar to roof level, looped it around and ran it back to below tank level to prevent fuel leaks if the car is rolled onto its roof. Last supersprint fuel was still coming out of this hose under cornering, so i had to block it and release the vacuum in the tank after each run.
All the other hoses coming off the tank/filler neck are either blocked or interconnected.

I was just wondering if anyone had some simple suggestions to stop this from occuring. I was pretty amazed that the fuel could have the momentum to make its way all the way to roof level, considering the car rarely has more than a quarter tank of fuel.

Cheers

just a sugestion, look into the 120ycoupe setup its got this crazy setup of mass pipes and this mini header tank thing..

Don't fuel filters have one way valves on them or am I dreaming? If so you could just use one without the filter; turned the wrong way around.

What diameter hose are you using? only 3 or 4 mm should be used. This is what the factory did. I agree the factory setup wasn't exactly 'race spec', but the smaller diameter stops the fuel getting too much speed up due to cornering G-forces.

There are air-return pipes to the filler neck, these are only used when filling the tank. If there are 2 breathers, then both can be fed back to the filler neck.

Curtis got it right:



Not all of the tanks have two breather connections on the top side of the tank.

This might help..
http://wiki.datsun1200.com/index.php/Fume_Control

Hmmmm, I think the hose I am using could probably be a bit smaller, I think its about 4-5 mm at the moment. I was also thinking that by simply putting a inline fuel filter in the breather hose, it might slow the fuel down enough to prevent it reaching roof level.
Otherwise I'll probably just get a longer piece of hose and loop it round above the tank a few times before heading up to the roof.
Thanks for all your suggestions guys

No, use the fuel filter the wrong way. this will allow air into the tank, but will block the fuel
coming out the overflow. Simple but true.

Thanks for confirming this mate, will do.

I know its getting a bit old but I found this photo on the Bprojects site and thought it was interesting, cheers!