Technical Help with Non Vented Gas Cap

Hi,

I have a 53 Chevy with a fuel tank that was custom fabricated but I don't know where the filler neck came from. I bought the car already done this way.

I need to get a non vented cap since the tank already has a vent outside of the trunk and I want to keep fumes outside of the trunk. In parallel I'm working on sealing up the entire trunk/floorpan from the custom C-notch work someone had done already.

Does anyone have some recommendations on how to get a non vented cap? The vented one on there is definitely the screw on type. Is it easier to remove the hose clamps and pull out the filler neck and put a new one that comes with a matching cap?

Thanks.

 

You don't want a vented cap in that trunk. I think what I'd do is pull the filler neck out of the hose, set it on the welding bench and drill a hole below where the cap reaches down in the neck and put a bung in it to connect a fitting to so I could run a vent hose up and out of the trunk. That way you won't get gas fumes in the trunk.

 

Thanks the tank already has a vent with a hose or hard line (I can't remember) running to the top of the rear wheel well.

Should I buy a new filler neck with matching cap? I imagine this is easier than trying to guess what non-vented cap would fit the neck in there right now?

 

You can get a non-vented cap from tanksinc.com, and probably speedway, summit etc. Not sure about that.

You will need to vent your tank at the filler neck, something like this (thanks to tugmaster for the shot)...

 

Most caps like that are not vented. That is why they say "remove slowly". Because there may be pressure in the tank.

 

buy this http://www.macsautoparts.com/ford_model_a/model-a-ford-radiator-neck-brass-twist-style.html

and this http://www.snydersantiqueauto.com/1810

The original Model A radiator caps were not vented. So make sure you use a radiator cap and not a gas cap. They look exactly the same on the outside.

 

Cool thanks. I already have a vent going from the tank to above the rear wheel well. Would I likely just need the non-vented cap then and no venting at the filler neck?

 

just curious...why do you think the cap you have is vented? looks like a typical modern sealed cap. It will let air in, but won't let fumes out. If it is letting fumes out, you just need to replace it...although figuring out what it's off of may be a challenge. look for a part number on it somewhere.

 

I need to take a look at it again, but a fellow HAMB'er came by and said to get a non-vented cap after taking a look at my car. He is way more knowledgeable than me so I'm going by what he had said.

I could take it off any take photos and upload tonight.

 

I'm pretty knowledgeable myself, but I make mistakes often. And sometimes I learn something from them...

 

I'll take a look tonight and let you know what I see. Thanks!

 

Here are a couple photos of the gas cap. I noted it having a part number 2083 and SAE PA66 on it but when I search online I don't find anything similar.

Do I likely need a different type of cap? The tank has a hose that vents in the rear wheel well.

 

Look in a west marine catalog for unvented gas fills

 

Virtually all of the gas caps at your local parts store will be non vented. I know this because I was looking for a vented type and could not find one at the major stores.

 

For a non-vented gas cap, look at the International pick up. I obtain one for my International, which was stainless steel, non vented, smooth face, with a grip around the edge. I cannot remember who the company was, but there are plenty out there. I would not be surprise if NAPA stocks them.

 

As mentioned the late model cap like you have will act as a unvented cap since you already have a vent on the the tank. If you are smelling fuel, it is either bad or leaking somewhere
else. Don't think you will find any other style cap that would fit that neck. Depending on the diameter of the fill tube on the tank, the easiest change would be a neck and sealed cap from tanks; looks a little nicer than the stock style cap too.

 

Not knowing where your vent is on your tank [i dont see it on the top where it should be] might it be under the fuel level? If so its not venting your tank .My opinion would be to go with the setup Big A posted and be done with it, have you got a pic of your existing vent position on your tank?Also buy a new cap.Napa can cross reference your part numbers.

 

Also, correct me if I'm wrong, but when I ordered my tank, I was told the vented caps only vent IN. It seemed correct because the vent is designed so the tank doesn't collapse on itself. Not 100% sure but food for thought.


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Here is a photo showing arrows that point to the hose that vents above the driver side rear wheel well.
So the cap I have is probably good enough, perhaps just a replacement to be on the safe side? None of the numbers on the cap show up with anything when I searched on google.

I'm not sure there is any fuel smell getting in the car from the tank. I know there is some smell near the carb that could get in from the firewall. I have another thread discussing an exhaust smell that has been collecting inside and my priority is to seal off the trunk floor by the C-notch, and seat back and firewall and rest of the cab. I originally thought the smell could be fuel but I've confirmed there is an exhaust leak in the pipes and therefore have taken it to an exhaust shop to have the pipes replaced and glasspacks put in.

 

ignore all other replies and get one of these. they have an o-ring inside and this cap seals tight, it is exactly what you need for a tank in the trunk. Speedway probably sells them. as for the vent, my friend had one of these caps/tubes in his car that had a little tube welded to the side to put a hose on. you could use this vent, or the one you already have

 

this is so typical of bagged cars, maybe that is why I hate them.

 

Thanks for the advice. I bought this car late December last year and had no real clue to look for things like this. In either case because I got the car at a great deal I can't complain too much having to take care of things like this. I'm going to see if I can find someone with a welder in my region who can help.

For the one you recommend, is the best source for the gas cap and neck Tanks Inc? Thanks.

 

I'm not sure where to get one, I took a quick look at Speedway but did not see them.... Summit? Jegs? I don't know who else is out there.

 

That aluminum threaded cap ( post 20 ) looks identical to what comes on "Tanks" 1932 repop tank. Be aware they come in at least two different i.d. There is a fat O ring inside it and they do indeed seal tight.

I have a couple of these and they're identical to each other other that the i.d.

Search Tanksinc check their site.

 

Cool I'll check Tanksinc thanks!

 

I measured the O.D of the neck I have right now and it is 2 inches. I can only find these ones that would fit 2" I.D hose (pictures below too):

http://www.fillernecksupply.com/servlet/the-3311/billet-aluminum-weld-on/Detail

http://www.summitracing.com/int/parts/tnk-fn-cc/overview/

http://www.ebay.com/itm/1982-83-84-...Parts_Accessories&hash=item338f8988e2&vxp=mtr


?

 

I'm leaning towards the last one since the cap might screw in the filler neck I already have. I'm guessing the threads are universal on those Gates plastic caps. Anyone have advice?

 

If your vent hose ends above the wheel well its still inside the car..

 

Thanks,
Sorry, the vent is in the rear wheel well above where the wheel rides or just to the side of it, I can't recall. This should keep the fumes outside of the car if I seal the cab and trunk and floors.

 

That is a vented cap, the fumes enter through the holes in the center and exit out the slits around the outside of the O ring. Get the cap in the last pic in post # 26. Done.