Another fuel tank vent question

[DLinson]

Does anyone make an aftermarket charcoal canister for fuel tank venting? I need to do something about the fumes, the wife doesn't like them so much.


Dennis

[parsonsj]

Dennis, my venting works very well. No fumes to speak of.

Tank opening goes to liquid/vapor separator, then goes to K&N crankcase breather (on the other side of the floor).

[Damn True]

Is that an OE part off another vehicle?

[parsonsj]

OE part? If you mean the liquid/vapor separator: No. Hand built by yours truly.

jp

[Damn True]

Surely you can't be serious.


You built it (shaking head in shame at my lack of fab-fu) yourself? How might one do that JP?

[thedugan]

Sorry for the dumb question.

Why do you need this?

I have a rock valley tank thats going into my 68 Camaro. Do I need a vent?

[parsonsj]

You must vent your tank somehow.

2 reasons:

1. It allows gurgle-free filling of the tank.
2. It allows air into the tank to replace fuel being pumped out.

jp

[thedugan]

Thanks John good information

So for a rock valley tank I do not see anthing on a vent. Can you give me any insite on what I should do to add a vent

[parsonsj]

Well, you've got a couple options. You can get a vented fuel cap. You may find that when you fill up that the pump shuts off a couple of times during fillup, but that's a minor annoyance.

The vented fuel cap will allow air in to replace the fuel volume pumped out. Drawbacks include allowing non-filtered air into the tank, and probably as gas smell to the vehicle, especially when the tank is almost full. But this was how all cars did it for decades.

Another option is to vent it in a similar fashion to what I did. Filtered air, and some effort to keeping the gas in the tank and allowing vapor out.

Or you can use the late model setup with a vacuum charcoal canister, purge valve, etc.

If you want to keep it simple and don't mind some smell, I'd just use a vented cap.

jp

[parsonsj]

Another thought: you might want to give Rock Valley a call. I bet they have a recommended way for their tanks.

jp

[thedugan]

Vented Cap on a 68 is hard. I wonder if anyone makes one that looks like the factory cap.

[Hammered]

Most vented caps are one-way and that's in. You need a two-way vent on an EFI car due to fuel heating/expansion.

[Steve N 69 69 69]

My Rock Valley tank came with a little tube welded in to the top of the tank facing toward the front. I have yet to hook up a line or filter to it, but I need to, so I can put more than 1/2 tank of gas in without it pissin' out the vent when I hit the brakes. I was thinking of using a rollover vent that summit sells for fuel cells. My thoughts were that the ball in it would keep the liquid from squirting out, but would breath openly when it didn't have gas pushing on it. does this sound like a plan? I dont really care if it smells like gas in the garage ( I kinda like it ) I just dont want to spill any on the ground. not at $ 4.80 a gallon.

[Hammered]

My Rock Valley tank came with a little tube welded in to the top of the tank facing toward the front. I have yet to hook up a line or filter to it, but I need to, so I can put more than 1/2 tank of gas in without it pissin' out the vent when I hit the brakes. I was thinking of using a rollover vent that summit sells for fuel cells. My thoughts were that the ball in it would keep the liquid from squirting out, but would breath openly when it didn't have gas pushing on it. does this sound like a plan? I dont really care if it smells like gas in the garage ( I kinda like it ) I just dont want to spill any on the ground. not at $ 4.80 a gallon.


Here's how I did mine: http://john.my67.net/engine3.htm

See the bottom of the page.

[Steve N 69 69 69]

Hammered, does that work?
I ran some 1/4" fuel line from the vent nipple, over the tank, then up to the top of the filler cavity behind the lic.plate ( about 4 FT. long) then I put a cheap plastic fuel filter on the end, to keep dirt out.
I thought this long tube going backwards from the vent would keep the liquid fuel in the tank, but with just 10 gallons in it, it was spilling out a little while cornering HARD up the Crest last Sun.
I think I still need some kind of ball valve deal.

[Hammered]

Well, I haven't been "cornering HARD up the Crest," but I've not been shy about the way I drive this car and I haven't had any problems.

It seems hard to believe that you would have problems with that setup. Are you sure the gas isn't coming from somewhere else, like the filler neck hose? I had to reposition mine after some spirited driving to seal a leak.

[Steve N 69 69 69]

Yeah, I really thought it was fixed too. But I looked at the little filter I put on the end of the tube, and there was 1/4" of gas in the corner. I did have it pointing down though, so maybe pointing up would work better. That way the little filter would act like a reservoir tip, and catch the fuel, then drain it back to the tank.

My rock valley tank is a few years old, and it has a welded on filler tube, so no leaks there. 'll get a hold of one of those sintered fitlers, and give that a try.

[CarlC]

Steve, you don't need much for a vent. I too have to make a vent system but what I'd like to do is use a larger hardline so that it is sturdy but have an in-line restrictor. Something large enough to allow air to get in/out but keep the big volumes of fuel from exiting. I'm also considering running some type of an extension above the restriction of the same size tubing to a filter. This extension length would hold the fuel that may pass through the restriction.

[David Pozzi]

Mary's 73 Camaro has a factory vapor separator. It's a rectangular box that is built into the rear seat back area, the part that supports the package tray. It's a rectangular box that is over a foot tall and 4 or 5 inches wide. The lower end sticks down through the floor and all the lines connect just above the rear axle.

There are several lines, I think two or three came off the fuel tank, one for each side and one from the center, the fourth line is to the charcoal cannister up front. Inside the separator I imagine the outlet pipe to the vapor cannister extends internally to the top, so no liquid can enter. The other lines that come from the tank, probably just enter the bottom and fuel can drain back from there.
David

[protour73]

Mary's 73 Camaro has a factory vapor separator. It's a rectangular box that is built into the rear seat back area, the part that supports the package tray. It's a rectangular box that is over a foot tall and 4 or 5 inches wide. The lower end sticks down through the floor and all the lines connect just above the rear axle.

There are several lines, I think two or three came off the fuel tank, one for each side and one from the center, the fourth line is to the charcoal cannister up front. Inside the separator I imagine the outlet pipe to the vapor cannister extends internally to the top, so no liquid can enter. The other lines that come from the tank, probably just enter the bottom and fuel can drain back from there.
David

Dave......am I to gather that Mary is NOT running the charcoal cannister? I decided not to reinstall that after my restoration, and thought the same............just to use that standpipe (the thing behind the seat) as a gas tank vent system. I'll have to look at my assembly manual to see which of the 4 tubes to use off that standpipe......2 unused gas tank tubes (stock tank) need to be routed up there, to the standpipe for venting.

[David Pozzi]

The cannister was removed before we got the car. It seems OK without it. No fuel smell in the garage.

[DeltaT]

You could also run an ignition-activated (or vacuum-activated) solenoid to your tank vent so it was only open when the car was running. That would solve the fumes issue when parked.

Jim

[Skip Fix]

My buddies asphalt Late Model just uses a loop of fuel ine and a regular fuel filter on the end so filtered air only gets in -no dirt dobbers!