Fuel Tank Vent Update 11/22

[mikester]

Throttle cables vary depending on 2 bbl vs 4 bbl. THEN, there's the whole distance from the bracket to stud issue. I about went nuts trying to find the correct bracket for my coupe. I think I wound up using a Pioneer CA8475 on my 81 with a Quadrajet

I think Ive got the cable issue solved. This vent thing has me stuck.

 

[500/600]

The only vented cap I’ve ever seen only vented inward so that as fuel was used it was displaced with air. It would not vent outward so temperature changes would increase tank pressure and push fuel toward the carburetor. If you are using a mechanical fuel pump then that second line is perfect for your vent. If in fact your cap is vented both ways then this whole exercise was unnecessary. I believe you did the right thing and a nice job of it.

Anybody please correct me if I’m wrong about the vented fuel cap and post the vented cap part number if you would.

 

[500/600]

It took a few days for me to get out there and take the tank out but I finally dropped it down yesterday morning and my buddy came over after work last night and gave me a hand getting it back in. Sucked for me because at the end of the day my leg looked like a sausage.
Im not exactly sure if I have it together correctly. I didnt tank any photos of the tank when it was out but this is the type of sender thats in it. I took this stuff apart so many years ago I dont remember what was there to begin with. Maybe it was a 3 line, maybe not. When I put the new tank in I had a 6AN fitting brazed on to the fuel line so I could run braided line. With a sender like this is the second line for the return ? Or is it for a vent ? If its actually for the return and theres no return line can it be used for the vent line ?

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This what I used for a vent but Im pretty sure the cap is also vented. Will this cause any issues ? If the caps vented do I even need this ?
Im down to the last little things to get this car finished. Now the biggest problem is my own lack of experience with this crap. As you folks have seen in my build threads there are some things that I can do on my own. Not perfect by any means but good enough. Now Im kinda stuck because I just have no idea what to do. Time to ask for help.
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Ask for help, it keeps us from getting bored. If I lived closer I’d be right there because I like working on other people’s projects better than my own.

BTW, expect every answer and opinion under the sun when you ask. I’m not sure how to help you weed through the crap answers on your own. PM the people that you trust. And be careful who you trust.

 

[565bbchevy]

Before I bought my new tank I read a lot of threads about replacement tanks not filling up correctly and people using their factory fill necks and putting them on the new tanks to help solve this issue but that didn't always work and since my original tank already had this issue I wanted to see if adding a vent would help with the new tank and because you are removing the cap to fill up a vented or non vented cap has no role in this issue.
With my new tank and sender and the added vent my fill up issue is non existent whether or not the new tank would have had the issue I can't be sure but it doesn't now regardless.

 

[TURNA]

I believe the reason the these tanks have this so called "issue" is very simple and overlooked.

For those who are old enough to remember the 70's and 80's, Do you remember how SLOW the pumps, pumped gas??????

Now fast forward 40 years and how fast the pumps, pump today.

That is simply the "problem".

 

[mikester]

The only vented cap I’ve ever seen only vented inward so that as fuel was used it was displaced with air. It would not vent outward so temperature changes would increase tank pressure and push fuel toward the carburetor. If you are using a mechanical fuel pump then that second line is perfect for your vent. If in fact your cap is vented both ways then this whole exercise was unnecessary. I believe you did the right thing and a nice job of it.

Anybody please correct me if I’m wrong about the vented fuel cap and post the vented cap part number if you would.

I'll get the part number off the cap if its not worn away.
I still have to put the plate pocket back in later today. One thing that I still dont fully understand. Until its upside down that Holley vent is basically just a piece of aluminum with a small piece of wire mesh at the end. How does that prevent fumes ? I can understand the charcoal canister but this has me confused.

 

[TURNA]

it doesnt

its just a vent

 

[565bbchevy]

it doesnt
its just a vent

Yup, really no different in concept from what I have for my fuel cell other than the loop in the line.

 

[mikester]

it doesnt

its just a vent

Yup, really no different in concept from what I have for my fuel cell other than the loop in the line.

So you guys are saying I'll still get fumes at this vent ? Thats the reason I put the thing in.

 

[565bbchevy]

So you guys are saying I'll still get fumes at this vent ? Thats the reason I put the thing in.

Well I wouldn't flick a lighter right next to it but both my cars are vented and in an enclosed heated garage and I have never had any fuel smell ever in there.
What exactly is your concern?