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Fuel Tank Breather


BugMan

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Just looking at the tank setup on my build, and seen a few peoples builds using a fuel filter in the breather tube.

Thinking about it has anybody use a non-return valve, like this?

https://www.amazon.co.uk/Fuel-Line-Return-Breather-Rollover/dp/B003UVZPI8/ref=sr_1_7?ie=UTF8&qid=1512948393&sr=8-7&keywords=Fuel+Tank+Breather

Take any feedback on this as an idea?

 

Steve

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Chris King

Not sure this would work. Injection systems need air to go both ways, so a rollover valve rather than a one way non-return would be ok.

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Dave Eastwood (Gadgetman) - Club Secretary

As a Chris said, if that is genuinely a non return valve and you have no other breather, give it a very wide berth; it could at the very worst cause catastrophic damage to your tank and or fuel lines. At best, it could distort the tank a wee bit.

Proper roll over valves have two way flow, it’s just that the flow out of the tank is limited by a spring release system. The tank needs to be able to equalize itself with atmospheric pressure. The internal pressure of the tank if it was sealed is constantly cpvarying over time, sometimes below atmospheric, sometimes above. So air must be able to move in and out.

Westfield tanks normally include a roll over valve/breather valve, it’s screwed directly into the top of ZK tanks, I’d have assumed likewise on FW tanks?

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Are, after posting the question, I remembered (in bed in the middle of the night) that there was a RED fitting on the top of the tank.

I'll investigate that later today.

So if that is the case, does this negate the need for a filter in the breather line that I've seen other use?

Once again thanks to all

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Adge Cutler- Dorset AO

Believe you'll find the red fitting is a rollover v/v. Fitting a simple (cheap) filter in the breather line was recommended to me to reduce fuel fumes, particularly when parked up in the garage. Seems to do the trick.

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Steve (sdh2903)

Yes the red fitting is the rollover valve/breather. The filter just helps keep the petrol smell in the garage down. It works too as I didn't fit one at first.

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Peter (Monty)

I went through a similar train of thought about the breather and fitted the filter in the end. The filter is fulfilling the same purpose as a carbon canister, just with much lower capacity. As the fuel heats up or during a refuel, vapour will be pushed out through the breather and be absorbed by the filter. Then when it cools down, vapour will be pulled back into the tank and out of the filter. That thermal cycle even happens between day and night without the car being driven. Fumes will only escape once the filter is saturated.

GXApI54.jpg&key=1738fa3099427a989bdf2875

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Brilliant team, I'll look for a suitable filter, any suggestions on Amazon or eBay as they are easily accessible for me?

Ironically tonight I've been going over all the fittings associated with the petrol system, and had a look in more depth at the RED fitting on the tank, and it turns out I'd been a bit of a numpty, thinking there was something in the tank, when it was the ball in the fitting.  Still live and learn

IMG_1831.JPG

After checking with Ian at WF I've had another go at using PTFE tape on these fittings, smaller ones needed about 6 to 7 turns, the bigger ones about 11.  Nice an tight, think this is good now, and I've master that bl**** stuff, finally.

IMG_1828.JPG

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Dave Eastwood (Gadgetman) - Club Secretary

Don’t think I’ve ever used that much tape.id be wondering about a thread mismatch, or poor cutting of one or other of them. (Unless it’s just some insanely thin tape!!)

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Adge Cutler- Dorset AO
3 hours ago, Monty said:

I'm now worried that I don't have enough PTFE tape on my fuel tank fittings :d

Mine have been fine so far, with nowhere near that many turns of PTFE. Was satisfied with how far the the fittings went in, and thread engagement.

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Have to say I hate PTFE tape, and generally anything to do with house hold plumbing, so being advised by WF to use it, my heart sank a bit. 

With regards to number of turns, I suspect it is a bit of trail and error.  I probably failed so much in the past thinking that pipe fittings were tapered, and the tape was to help it close up the gaps as well as seal it, which I now think is not the case, and my previous attempts of 3 or 4 turns were not enough.

I started on a non important fitting, and tried 4, 6, 8 and then 9 or 10'ish which then seemed a good interference fit.  I suspect it very much depends on technique and how good you are with the stuff, and probably on the quality, width and thickness of the PTFE being used.

At no point did I feel the fitting was approaching its limit, I'm sure there must be something like Stud-Lock that would do the job, but I'm sticking with this for now, now I have 4 or 5 fittings under my belt.  As with many things I think its down to practice and confidence.

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