givemethebighammer
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| posted on 27/7/04 at 09:35 PM |
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Bicycle tyre valve fuel tank vent
Seem to remember someone talking about modifying a bicycle tyre valve for use as a fuel tank vent. Does anyone have the details on how to do this ?
thanks
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JoelP
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| posted on 27/7/04 at 09:51 PM |
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madness, i was going to post this very one earlier! It was Jon who first posted the idea, so he might know. Im going to use two, opposite way round to
let air in and out. i reckon to get a pair from a cycle shop, drill a hole (plastic tank) and use some dappa glue to stick it in.
anyone see a reason why this wont work? or suggest a good glue? i have access to a few contact adhesives and similar stuff thru work.
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Viper
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| posted on 27/7/04 at 09:52 PM |
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shouldnt the vent breath in both directions to allow for expansion (hot weather) as well?
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RoadkillUK
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| posted on 27/7/04 at 10:44 PM |
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Original Thread
Above is the original thread where it is explained.
As for putting 2 opposing valves in series, surely it won't work because one is designed not to let air in and the other not to let air out.
HTH
Roadkill - Lee
www.bradford7.co.uk
Latest Picture (14 Sept 2014)
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Mark Allanson
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| posted on 28/7/04 at 06:00 AM |
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I did a thread about this a while back, the tyre valves have a 2PSI threshold, so when you have two opposed ones, if the pressure gerts to 2PSI - it
vents, and if the vacuum gets to -2PSI, it draws air in. The net effect is your tank pressure is stabalised and still sealed from the atmosphere
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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JoelP
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| posted on 28/7/04 at 07:12 AM |
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yep, the valves arent in series, they are side by side in parallel. hence as mark says, 2 psi either way.
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stephen_gusterson
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| posted on 28/7/04 at 08:36 AM |
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aquarium shops sell little plastic valves that are intended to stop water syphoning out of a tank once an aerator pump stops.
As these valves open for a weedy air pump, and can be blown open by breath, and have symetrical 5mm approx tube stubs each side, might be a bit more
friendly than a tyre valve............
costs about a quid
atb
steve
 
Rescued attachment checkvtetra.jpg
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Steve Hnz
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| posted on 28/7/04 at 10:37 AM |
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But probably melt in petrol fumes!
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Hellfire
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| posted on 28/7/04 at 11:30 AM |
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Why bother with valves at all? A piece of rubber tubing with a downward return works fine.
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stephen_gusterson
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| posted on 28/7/04 at 12:15 PM |
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not necessarily
many cars have plastic fuel tanks.....as are fuel cans nowadays
just drop a valve in some petrol for a day or two and see if its compatable.
atb
steve
quote:
Originally posted by Steve Hnz
But probably melt in petrol fumes!
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givemethebighammer
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| posted on 28/7/04 at 02:22 PM |
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OK so where did I go wrong ?
see attached picture, used a plastic "Y" connector (from motorfactor, assured petrol OK)
and two old bike valves mounted in opposite directions. Tested the thing by pressurising the pipe that will connect to the tank and....
nothing, managed to get 40psi in the tube and the valve did not open.
?
[Edited on 28/7/04 by givemethebighammer]
 
Rescued attachment ventweb.jpg
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givemethebighammer
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| posted on 28/7/04 at 02:27 PM |
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Just a thought I shouldn't be using a Woods / dunlop type valve rather than a Schrader ? should I
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NS Dev
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| posted on 28/7/04 at 04:19 PM |
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As Hellfire says, why bother with the valve at all? I never have done, just a loop of small bore (I use 3/16 brake line) from the top of the tank to
below the car's floor level, works fine on my car (s)!
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NS Dev
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| posted on 28/7/04 at 04:20 PM |
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Meant to add, make it from the centre of the top of the tank so when the fuel is surging about it doesn't surge up it too much.
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ernie
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| posted on 28/7/04 at 04:45 PM |
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tank vent
I asume you need a non return vent to stop fuel spilling out if you unfortunatly turn it over as in racing
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Viper
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| posted on 28/7/04 at 04:51 PM |
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In racing you are allowed to "loop" the breather pipe rather than have a valve.
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givemethebighammer
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| posted on 28/7/04 at 09:29 PM |
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you are missing the point guys, I know a loop of tube will do the job but I'd rather have some sort of valve(s) in the tube to seal the tank
from the outside world unless it needs to vent or take in air. Bike valve sounded ideal solution.
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NS Dev
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| posted on 29/7/04 at 07:31 AM |
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yes, but when the engine is running it will be constantly drawing fuel out of the tank anyway and thus will be venting all the time anyway!
As Viper says, a loop of pipe works fine, that's what I use on my cars.
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stephen_gusterson
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| posted on 29/7/04 at 09:39 AM |
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que?
the fuel drawn out and returned to the tank doesnt vent anywhere outside the tank, so you still have a non vented situation!
The fuel being sucked out and used by the engine may even cause the tank to collapse on itself if it doesnt vent. Or fuel flow to stop.
Also, if you have a lot of heat under the bonnet, the fuel thats returned will be warmer, will expand in the tank, and actually have the opposite
effect.
Jag XJ-S, with their hot under bonnet temperatures, warm the fuel in the tank
syds metro idea sounds cheap and workable. My C reg metro turbo had this device stuffed up the B pillar on the drivers side. This is the metro type
that had the filler behind the drivers door opening just behind the B pillar, not the rear of the side where later ones are. You can acess it by
removing the drivers side passenger trim panel.
atb
steve
quote:
Originally posted by NS Dev
yes, but when the engine is running it will be constantly drawing fuel out of the tank anyway and thus will be venting all the time anyway!
As Viper says, a loop of pipe works fine, that's what I use on my cars.
[Edited on 29/7/04 by stephen_gusterson]
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givemethebighammer
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| posted on 30/7/04 at 12:51 PM |
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quote:
Originally posted by Syd Bridge
Metro's have got a neat little valve. The one's I've removed have been on the drivers side, between the inner panel and body. Use
them on the off-roaders, street-rods, and the Locost.
Cheers,
Syd.
Syd what am I looking for ? What's the easiest way to get to and remove it ?
thanks
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