[falco_dave]

Long time lurker here. So far all of my questions have already been answered by doing searched. Thanks to all that have posted their knowledge and experiences here.

So I have been running my fuel lines and wondering what to do with the vent from my fuel cell. Based on this forum, I decided to DIY my own vapor canister. I used a stainless steel drinking bottle, a bulkhead adapter, activated charcoal and fine steel wool. Total cost is about $25

The vapors enter via a 3/8" barb fitting secured into the bulkhead adapter. I have about 3 inches of firmly packed steel wool on each end with about 4 ounces of activated charcoal in between. The vent line is 3/8" with about 70 1/8" holes on the far side of the canister, drilled completely around the bottle. The cap is secured using a cotter pin. By removing the cotter pin the canister can be serviced with new steel wool and activated charcoal.

It is temporarily mounted with zip ties until I can get some hose clamps that are large enough. Thoughts please.

 

[Mikey_P]

Looks a whole lot nicer than the lawnmower gas filter I used. Really clever!

 

[ROADRACER83]

Good solution

Way to go!! It meets all my criteria. Cheap, effective, looks like a production part.

Ron

 

[Tennessee Tim]

Question - I have seen a number of these home-made vapor canisters, and the one thing that seems to be lacking in all of them is a purge circuit. I would expect that the activated charcoal would quickly get saturated and quit working without any purge capability. Can anyone give me an idea of how long their canisters last before getting saturated and fuel odors becoming apparent?

Tim

 

[AC Bill]

Good idea Dave..looks far prettier than the ones made out of plastic pipe.

I hope you mount it higher up on the frame than you have it pictured currently. I would be afraid that it may act as an overflow bottle if the tank was filled to the tits.:w00t:.
I'm pretty sure you'll want it positioned higher than the the top of the tank..and I believe, preferably close to the same height as the filler pipe.

Tim, good question! I am using the donor canister for my vent filter.. and so far so good. If its open to the air, I would think that it would simply evaporate over time.

 

[falco_dave]

In reading about the Fuel Safe fuel cell, it is suppose to have an anti-tip over valve in the vent. I have asked Fuel Safe if that is true, still waiting to hear back from them. I wonder if that would act as a discriminator valve to allow vapor without allowing liquid through.

As far as the actual mounting location, it is TBD but I am considering zip tieing it to the actual filler tube. I want to have the body on before the final mounting is done.

 

[rscocca]

In reading about the Fuel Safe fuel cell, it is suppose to have an anti-tip over valve in the vent. I have asked Fuel Safe if that is true, still waiting to hear back from them. I wonder if that would act as a discriminator valve to allow vapor without allowing liquid through.

As far as the actual mounting location, it is TBD but I am considering zip tieing it to the actual filler tube. I want to have the body on before the final mounting is done.

I have the fuel safe as well, I installed the decriminator valve (Largest Fuel safe has, so as to not have blow back when filling) up as high as I could on the fill tube with a filter attached to it. The roll over valve works when the car rolls over not when filling up the tank, on mine it is a metal ball, it wont float.

 

[BigLeo69]

mess with people and get a NOS sticker and put it on:evil:

 

[Tennessee Tim]

Tim, good question! I am using the donor canister for my vent filter.. and so far so good. If its open to the air, I would think that it would simply evaporate over time.

Well, while it is evaporating from the canister, more fuel vapor is entering the canister. Eventually, equilibrium would be reached and it would be as if there were no canister. Additionally, evaporation from the charcoal (technically it would be desorbing, not evaporating) would release the vapors to the surrounding area (like the garage) giving rise to the fuel odors that the canister is intended to prevent.

That's why evap systems have a purge circuit. Running fresh air through the canister will quickly desorb the fuel vapor and it is routed to the engine and burned. Without a purge circuit, the canister should quickly saturate and essentially become trasnparent to the fuel vapor. I have no idea how long "quickly" is, and it would depend on the amount, quality and particle size of the charcoal, but an educated guess would be days, not months or years.

I have seen a number of threads about home-made evap canisters, and I have struggled with why they appear to be working longer than a few days. Either there is just not enough fuel evaporation to create an odor problem to begin with (meaning the canister isn't really doing anything) or the more disturbing option is that as a physicist, I don't understand the physics of what's going on...

Or, there is always the possibility that there is a third option that I haven't thought of.

I will probably end up doing something completely retentive like monitoring vapor emissions around the car both with and without a canister...

Tim

 

[dv/dt]

I have seen a number of threads about home-made evap canisters, and I have struggled with why they appear to be working longer than a few days.

Tim

Third option - While the engine is running it will suck fresh air into the tank via the vent as the fuel exits to go to the engine. So it is always desorbing when the engine is running and only absorbs when the engine is off and the fuel expands due to temp increase or atmospheric pressure decrease.

Cheers, Rod

 

[Tennessee Tim]

Third option - While the engine is running it will suck fresh air into the tank via the vent as the fuel exits to go to the engine. So it is always desorbing when the engine is running and only absorbs when the engine is off and the fuel expands due to temp increase or atmospheric pressure decrease.

Cheers, Rod

I thought about that, and it could be the explanation. I didn't think it was credible because the typical outing would only run a few gallons of air through the canister whereas, the fuel tank will sit for many hours loading the canister up when the car is not being driven. Gasoline has a relatively high vapor pressure and will feed the canister with a small but continuous stream of vapor when the car is not being run. But then, I haven't done the math (I'm not sure the math can be done), so it could certainly be the explanation.

I suppose it is of academic interest anyway, since the home-made canisters seem to work. I plan to add one.

Tim

 

[oldguy668]

It takes more than fresh air to purge the media. It takes heat and/or vacuum.

 

[Matt Ries]

If running EFI why not just use the factory canister and purge valve, less work than a custom system and no math!

Matt

 

[G-Pete]

Just wondering how we managed to drive cars for almost 100 years without a charcoal canister...:001_rolleyes:

 

[oldguy668]

The evaporative emissions absorbers aren't to make the cars run better, they are to make the tree-huggers feel better.

 

[1fastsedan]

Love it! And just so you know, I'm stealing the metal water bottle idea. :001_smile:

 

[dwleo]

I didn't install one in mine; just ran the tube out and attached it to the frame. No odors; even when locked up in garage for two weeks while I was on holidays. Not a whiff!

 

[falco_dave]

Per rscocca's suggestion, ordered the in-tank discriminator valve tonight. Thanks all for the feedback!

 

[hamadryad]

Vapor canister

I have a custom built SS gas tank between the frame rails in my pickup truck. There is very little room for the vent. I recently bought a vapor canister from II Much Fabrication. (Hot Rods By Dean also make one) I am mounting the canister up in the rear fender well so the 3/8 hose from the vent goes vertically up to the canister. The canister is vented through a sintered bronze vent. With this or any home built canister, the big thing is to not have any low spots where gas vapors or raw gas can collect. I'll post a pic when it is complete and let you know how well it works.

 

[Rich A]

falco_dave,
Looks great, but like Matt Ries says "If running EFI why not just use the factory canister and purge valve, less work than a custom system and no math!".
I'm sure it would cost less than $25 from Ecology/Pick a Part/Pull a Part.