Do I really need to spend 50 quid on a Mocal two way valve?

I have been searching all forums and tinternet and it certainly looks that way...........

Help appreciated as always

not really, you can in theory wrap pipe of hose around the tank, so there's always a high point in the breather pipe, no matter what way up the car is.

best way is to fit a valve. its neater, smaller, and probably better for IVA

but what always gets me, is that in everyone's build photos, I dont think i've ever seen anyone on here fit one...

You should really have a 2 way valve with rollover protection, that's what I fitted to mine. Lets air in and out but shuts off is fluid hits it.

I think Mocal valves are worth it, you can fit a swan neck tube tube and a roll over valve but the Mocal is better.

http://sylvabuild.blogspot.co.uk/2013/12/fuel-system-modifications.html

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

Good luck

I used on of these, IVA man happy with it.

http://www.demon-tweeks.co.uk/motorsport/fuel-tank-vent-valves/atl-tank-vent-valve-6-vent-inline-to-suit-6-hose-3-8-hose-barb

Renetom, im on injection.
AndyW, will my tank implode because it's getting sucked in?

Surely if the fuel cap is vented then I just need the anti spill type valve?

To be clear, not intending on racing it, can add a mocal later for track days.......

The valve lets air in as the tank level falls
That's it .
If injection causes the tank to be pressurised by the return
then you will need the all dancing one.

Don't forget that if you park the car outside on a sunny day the petrol will heat up, expand and pressurise the tank, hence why you should use a 2 way valve.

quote:

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Originally posted by wombat
Renetom, im on injection.
AndyW, will my tank implode because it's getting sucked in?

Surely if the fuel cap is vented then I just need the anti spill type valve?

To be clear, not intending on racing it, can add a mocal later for track days.......

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I fitted 2 valves 1 is a cheap snorkel ball roll over so closes when car upside down therefor tank breaths in normal operation
I ran a small tube from tank high up
Second breather is a simple one way valve plumbed off the fuel filler hose to draw air as fuel is used, this will close if car upturned