Venting meth tank

[f-castrillo]

So a few months ago, I installed my DevilsOwn meth kit. All went well, except that when I topped off my tank via the remote filler spout, water/meth would leak from somewhere around the tank cap and I'd see it all over my garage floor within minutes. I finally found time to remove the bumper and inspect where the leak might have been coming from, and found that it was leaking through the tank cap's threads. See my crude MS paint diagram below.

methtank.png

Please note that in the process of connecting the rubber hose from filler spout to my tank, I drilled a hole in my tank cap, and got rid of the inner disk thingy that sat at the top of the inside of the cap. I believe that inner disk was preventing fluids from leaking through the cap threads, and the removal of the disk caused fluids to leak out upon topping off.

When I found the source of the leak, I promptly proceeded to seal off the lower edges of the tank cap with a silicone based sealant. I topped off the meth tank just to make sure it did the job, and it did: no more leaks.

Woo hoo, right?

Not reallly.

Just tonight, I noticed my DO controller's yellow light flashing, i.e. fluid levels are low. So I get home, and start to pour in the remainder of my meth supply. The filler spout quickly filled and drained into the meth tank at a much slower rate than normal. The quick filling of the spout forced me to put my supply down several times while I waited for the spout to drain into the tank.

That's when I realized the problem was coming from the sealed leaky area. Although fluids leaked through the cap's threads, it also served as the only source of ventilation for the tank. Sealing it meant that air could not escape as fast as meth filled the tank, leading to slower overall fill time.

So my question to you all: is this lack of ventilation detrimental to the proper operation of my WMI system? Obviously it takes longer to fill up now, but would this somehow cause unneccesary strain on my meth pump? The filler spout that I use has a "vented buttress threaded cap" (this is the exact one: Flambeau Fluid Systems Remote Filler Spout 066023), so I imagine the answer is probably "no", since the meth tank can use this as a vent source while not actively being filled.

Also, if I decide to fix things by making a new hole in the existing cap, do I run the risk of my meth evaporating quickly? Or is the rate of evaporation slow enough that I wouldn't have to worry about it?

[Atlanta]

That's a damn fine question. No answers but inquiring minds want to know!

Sent from TapaDatAss

[f-castrillo]

I feel like it's going to be OK, but I'm gonna refill my meth to the top, and I'm cringing at the thought of how long it might take to fill.

I'm going to summon people who might have an idea of the best course of action to take...

@rfinkle2
@bioevolve
@pharoh
@DevilsOwn

[Broxer]

I would think you'd need some ventilation. when the pump is sucking the meth out of the tank it needs to be displaced by air. If its not able to do that then it will create a vacuum and stop flowing or collapse the feed line.

kind of like if you epoxied a straw in a cup so it was air tight, air wouldn't be able to displace the liquid so you wouldn't be able to suck any fluid out without collapsing the cup.

[rfinkle2]

What Broxer says about the ability of the meth to be displaced makes perfect sense.

@cld12pk2go would know for sure, as would @Ziggo.

[pharoh]

The remote filler spout I used had a vented cap for that purpose.

[helmetface]

Originally Posted by f-castrillo So a few months ago, I installed my DevilsOwn meth kit. All went well, except that when I topped off my tank via the remote filler spout, water/meth would leak from somewhere around the tank cap and I'd see it all over my garage floor within minutes

May I see a picture of your remote fill setup? Any chance you have pictures when the bumper was off?

Thanks!

[SLOWHATCH]

I'm with Broxer on this one. Can you somehow make it ventilate from the filler spout? Or just make a tiny hole in the tank cap.

[Alejo_NIN]

isn't meth volatile, meaning, it will evaporate like alcohol does?
if so...you will need to run two lines to the front of the car and use on as the return.
just like the gas tank in your car. it has a breather, but at the front so as to not create a vaccum.
as a matter of fact, you could use one canister, just like it has at the front for the gas ventilation.
like other have said, you don't want to close it 100%, but venting it the way you are would just evaporate and the meth won't last you at all.

you also need some kind of a ONE WAY VALVE so it doens't spill back out when you hit a bump or something

[f-castrillo]

Originally Posted by Broxer I would think you'd need some ventilation. when the pump is sucking the meth out of the tank it needs to be displaced by air. If its not able to do that then it will create a vacuum and stop flowing or collapse the feed line. kind of like if you epoxied a straw in a cup so it was air tight, air wouldn't be able to displace the liquid so you wouldn't be able to suck any fluid out without collapsing the cup.

Thanks, that's exactly what I realized. My remote filler spout has a vent that seems to be sufficient for my setup, i.e. I haven't had any issues with the feed lines crushing themselves, or BATs not acting right, etc. See image below.

Originally Posted by helmetfail May I see a picture of your remote fill setup? Any chance you have pictures when the bumper was off? Thanks!

See below.

Originally Posted by SLOWHATCH I'm with Broxer on this one. Can you somehow make it ventilate from the filler spout? Or just make a tiny hole in the tank cap.

My filler spout has a hole it can vent from. See image:

IMG_20110919_224839.jpg
IMG_20110920_111201.jpg
IMG_20120402_151519.jpg

Originally Posted by Alejo_NIN isn't meth volatile, meaning, it will evaporate like alcohol does? if so...you will need to run two lines to the front of the car and use on as the return. just like the gas tank in your car. it has a breather, but at the front so as to not create a vaccum. as a matter of fact, you could use one canister, just like it has at the front for the gas ventilation. like other have said, you don't want to close it 100%, but venting it the way you are would just evaporate and the meth won't last you at all. you also need some kind of a ONE WAY VALVE so it doens't spill back out when you hit a bump or something

Interesting idea... Can you elaborate a little more? I'm having a hard time visualizing it

Thanks for the replies, guys. I'm off to do some quick grocery shopping, refill my 5 gallon meth jug, and check back in later. The easiest thing to do at this point for me is to leave it as is (unless the vent in the filler spout isn't big enough). I could go back in and punch a small vent hole in the tank cap with a thumbtack or something lol, to fix my filling problems.

[helmetface]

Originally Posted by f-castrillo See below.

Thanks Cast, is that filler tank something that came with your DO kit? If not, where did you buy it?

Thanks..I'm definitely stealing this idea.

[f-castrillo]

Originally Posted by helmetfail Thanks Cast, is that filler tank something that came with your DO kit? If not, where did you buy it? Thanks..I'm definitely stealing this idea.

I stole the idea from @bioevolve lol. Check this page, its the first one on the list. You have to call them and order that way. http://www.flambeaufluids.com/compon...ts_matrix.html

Sent from my Galaxy Nexus

[skeurton]

Originally Posted by Alejo_NIN you also need some kind of a ONE WAY VALVE so it doens't spill back out when you hit a bump or something

This is exactly what I was going to do since I'm planning to mount the tank in the hatch. Would something like this work?

Dorman Products - 47149



I was thinking of drilling a hole in the cap, putting a grommet in, and sticking the check valve in. That would allow the tank to suck in air when the pump is pulling meth from the tank, and keep it sealed when it isn't, right?

[BigRedSpecial]

Interesting setup, I may copy you when/if I go meth.

One idea to speed up the fill is to place a small diameter hose (I'd use a piece of heatshrink tubing) inside the hose, so that the bottom is just sticking into the meth tank, and the top is almost to the top of the filler tank - above the top level of the meth while you're filling. That way the air in the main tank has a route out and the meth displacing it can flow much faster. Think pouring from a jerry can with the vent closed vs. open.

[BigRedSpecial]

This is what I mean if it didn't make sense:


The blue is the meth level, black is your filler hose, and the red (looks grey for some reason) is the smaller hose/heatshrink/whatever.

[Dust]

Simplest way would be to put a one way check valve at the top of the bottom tank.
or
make the fill hose bigger so that air can escape faster
or
add a hose from the top of the bottom tank to the top of the top tank so that air can vent back to the top of the filler tank, and you can have a vent for both hoses (allows less vaccum build up)
or
add a hose to the top of the bottom tank, and plug it. Unplug the top when you are filling so that air has a place to escape

The Subie guys have this problem when they try to use a surge tank for the STI 12L tank that mounts to the backseat.

[f-castrillo]

Any suggestions on what kind of check valve to use? I'm a noob when it comes to figuring some of this stuff out lol. I understand the concept, I just don't know if there's a recommended type of check valve for this situation

[Dust]

I am doing it the opposite way (check valve to relieve pressure, not vacuum), because I don't run alot of meth, but here is a pic. Install it the other way (only let air out), and then keep it above the fluid level or looped to keep it from pushing out meth.