Landracing Forum
Tech Information => Technical Discussion => Topic started by: Jon on January 12, 2012, 06:52:55 AM
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Hi
Can anyone recommend a Fuel vent rollover valve that will work at 90 degrees.
I'm putting together a streamliner bike & the valve I've bought doesn't close off reliably until it is about 135 degrees, I don't want end up with the bike on it's side leaking fuel.
Thanks
Jon
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Jon, you should have a tube on your rollover, put an S in it on the way to the bottom of the tank, make the s the same width as the tank. That way your rollover will not leak gas regardless of position.
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Same thing with a vent tube that runs diagionaly from one corner to the opposite corner then past the bottom of the tank, only 1 90 degree bend so that you do not create a "P " trap -- make it fairly large, as large as your fuel line.
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Thanks for your help guys, I appreciate it.
Jon
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PS I would put it on the rear corner for salt racing as your G loads will be much greater with the chute than it will with accelleration
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Hi jon I got a one way vent from Earls performance plumbing it wasnt to dear but works perfect at what seems any angle
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Thanks Oz, does gassing out of fuel pressurize your tank mitch or does it bleed off pressure?
Thanks
Jon
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It has a little ball bearing in it and as the fuel gets used lets a little air in cant push anything through the other way fuel air nothing goes back through I have tried and its a pretty little anodised thing with a NPT or BSP thread so dead easy to fit.
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I fitted something like that to my manufactured fuel tank on my bike this year and was not real happy with the potential shake or bump spillage or the action of the ball so put a light spring behind the ball
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The simplest is a hose that comes out of the top of the tank, down one side, accross the bottom, up the other side, accross the top and is tie wrapped to the fitting coming out of the tank. This isn't elegant but it works, requires nothing inside the tank, has no ball or spring to stick and vents in both directions without restriction. It also will spark no discussion in tech.
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Jim that can P trap, and block the venting --and has caused engs to lean and blow up... from one corner across diaogonally and down the corner,to below the bottom of the tank will work and will not P trap
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P trap? Not familiar with the term.
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Maybe not the term, but the item. They're the bit of plumbing that keeps nasty smells from escaping the drains in your toilet and sinks. Shaped kinda like a sideways letter "P" 8-)
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every sink and toilet has a p trap.
some have s traps.
they hold a "block" of water at the lowest part of the plumbing ,
right below that fixture.
they prevent gasses, air, stink or what not from passing through
the next straight section of pipe, upward.
a liquid lock as opposed to a vapor lock. (?)
a liquid lock will cause a vapor lock.
correct?
franey
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it took 10 minutes to post that, but conirms slims post.
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Ah I see. In non rollover conditions how does the liquid get into the loop?
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Fuel pump?
DW
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Into the vent line?
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G force or slosh from gear changes
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Sorry Jim,
As soon as I hit send I knew I was wrong. Then I could not find the thread to correct.
Mi Culpa(?)
DW
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MERLOT :roll: :?
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G force or slosh from gear changes
15 gallons in a 20 gallon tank and a powerglide, but I can see if the tank is full and using a clutch.
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Sorry Sparky,
On a diet - Chardonny tonight. Joanie out of town, I will have to replace bottles tomorrow.
DW
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I've used some one way check in fuel vent line valves that "crack" at 0.5 psi on applications with electric fuel pumps that have worked real well for us. They are available at mcmaster fairly cheap. Only problem is that do not vent both ways and we noticed a little tank pressure when we remove the cap for fill up. I don't know if this is a legal way of venting but our install was on high hp street rods so we didn't have to go thru tech.
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I always wondered if John Crapper included a "P" trap in his original flush-fixture.
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I suspect that came shortly thereafter for obvious reasons.
Doug :cheers: :cheers: :cheers: