My confusion lies in the fact that our oem tanks have a side vent tube, but when I look at "oem style" caps, most of them are vented. What was oem on our cars? Did they use both a vent tube and a vented cap?
I welded my oem vent tube shut ans installed a vent with rollover protection when I installed my in tank fuel pump, so I would like to stay with a non vented cap so I don't lose that rollover leak protection. Any problems with that?
btw, I also rerouted my vent tube for a simpler installation. It uses the same outlet above the license plate, just gets there in a more direct fashion.
All the cars were vented EXCEPT wagons, rancheros and the delivery.
I think that is backwards. The wagons and rancheros were vented caps. All others were non vented caps. The fill tube is so low and in the back of the tank. If the cap was vented, gas would surge out onto the ground every time you took off. If the cap was vented, there would be no need for the vent tube system. The wagons and rancheros have no vent tube and therefore require a vented cap.
I'm guessing by "all car were vented except..." Bill was refering to the vent tubes. OK..sounds like a non vented cap is in order...cool, I saw a neat NOS non vented stainless one on EBAY...I'll see if it's still there.
thanks guys
Gary is right, my ranchero tanks have only a fill neck, and a gas line fitting. I had this conversation today, as my cap leaks when I fill the tank. So I a as wondering which cap to order
Sorry for the confusion, the car tanks are vented, Rancheros, Wagons and such have vented caps.
Quote from: Frankenstein57 on 2014-07-05 00:02
Gary is right, my ranchero tanks have only a fill neck, and a gas line fitting. I had this conversation today, as my cap leaks when I fill the tank. So I a as wondering which cap to order
I've been fighting this on my Ranchero and have tried and ruined several caps in the process. Any replacement cap that says it is Vented is only vented in one direction to let air in, this was an EPA regulation put into effect in the early 70's from what I have researched . When mine sits in 90-100 degree weather it builds up pressure as the air and fuel expand. Take the cap off and the pressure coming out will almost blow you over and if the tank is full enough it will cough out some gas too. I have actually heard the tank oil can when the cap is removed and the pressure is relieved. I've read several posts where guys with early Ford trucks and a lot of early Chevys have the same problem with non vented systems. The solution most guys have done is drill a small hole in the cap to let it vent. That is what I have ended up doing, 1/8 hole. It's working so far after several other failed attempts on other caps.. I know, not the safest thing to do but until someone comes up with something better or I can locate an original vented cap...
I had a 1932 Roadster, and had a similar gas tank venting problem on that car. The 32 had a low mounted rear tank, with a "low filler" cap mounted on the rear (almost like a 57 Ford car). If you filled the tank, left it in the sun, it would expand the air pocket inside the tank and start forcing gas under air pressure out of the gas cap.
My solution was to drill and tap a hole (1/8th NPT) in the side of the boxed frame under the car. I then installed a (1/8th NPT, and Nipple End) Ford in line fuel filter like was used on the front of a Autolite carb into the new tapped hole on the frame. This served as the "filtered inlet" point for my fuel tank. I routed a 5/16" hard line from the inlet filter, up as high as possible inside the trunk, and then back down through the floor, and connected to a vent on top of the fuel tank. The high loop of the line was a air lock to prevent fuel from being pushed up the line into the fuel filter.
It worked just fine for 12 years, until I sold the car. Just another idea.
Oddly enough, the description of the caps for sale are very confusing. Looking at muliple pictures trying to figure out why a non-vented cap was exactly that and vice versa, I realized the descriptions given were almost always the same....and that the desriptions usually given were actually for the type of tank, not the cap itself. For example..when I first looked at "vented gas tank cap", I assumed the "vented"was refering to a vent in the cap, but that's not the case..it's refering to a cap for a vented tank. So, the neat nos cap I found described as a "non-vented cap", actually had a vent in it.
Is it just me, am I the only one who confuses this easily, LOL?
BTW, there is a NOS '57 Ranchero cap for sale on ebay....80.00!!
Quote from: RICH MUISE on 2014-07-05 23:59
Is it just me, am I the only one who confuses this easily, LOL?
Not just you....there are many things that confuse me....
http://57fordsforever.com/smf/Smileys/default/deadhorse.gif
This is being written as a question...Isn't it common for gas caps that vent to have a built in check valve that rattles if you shake the cap?
don't know the answer to that one, but here are some pics to explain my confusion: both are described as vented..but I think only the top cap is. Just a guess, but I think the vents are a "channel" embossed into the inner piece that runs out beyond the filler neck outer dia.
The cap in the bottom two pics don't have that feature, and imho are for a vented gas tank
well, those pics are useless...too small.
EDIT..fixed them. here are pice of the neat nos cap I was hoping would work, but I think the "cutouts" on the side are actually a venting feature...just a different style than the one posted above....what do you guys think?
Rich: I'm with you on the confusion, I'm starting to think a vented marked cap means it's for a vented tank and non vented is for a non vented tank just as you thought., and just the opposite of what I was thinking and all my failures with the vented caps.. I should have bought the original cap on Ebay, I've already wasted that amount on my failed experiments. My next move will be trying a non vented cap.
Gasman: Yes the newly produced vented caps have a spring and valve that rattle, the problem is they only vent in one direction. I've even tried removing the spring and valve but it still didn't let pressure out on the one I tried.
In 1957, nobody cared if the gas tank vented into the air. If the gas expanded too much, it dribbled on the ground. Who cared, it was twenty cents a gallon!!! I wonder if the check valve vented gas cap is the only style of vented gas cap manufactured today. Since when...1974??, all gas systems are closed and vent via a charcoal canister. If I remember correctly, way back when, on a hot day when you removed a gas cap, it could go into orbit from pressure in the tank. Even farm equipment had check valves in them so gas wouldn't slosh out.
Pressure in the tank tests the needle and seat in the carb!!!
If I remember correctly the new EPA mandated style gas caps went into effect in California in 1970 and the rest of the country in 1971.
this is something I have also been trying to figure out with my ranch wagon. I bought a 'vented' cap but if you blow into it (as in air coming out of tank) nothing passes through. After reading the above posts about the regulations I thought I would try sucking on the 'vented' gas cap and sure enough, air comes in. So the cap allows air into the tank but doesn't let it escape.
I have had the cap on there for 5 years, and today I had to change my fuel pump - someone told me all that pressure could have ruined the pump. Tomorrow I will drill a hole in the gas cap...
Anybody use or adapt something else?
Matt
I would think the wagon/Ranchero guys would be best off trying to fing a NOS eom design cap rather than a new one that has been epa regulated. As I mentioned, one just needs to figure out when reading the description of the cap if the "vented" is refering to the cap or the tank it goes on.
I've now spent more time reading posts about vented vs non vented caps then I would have liked to. We are not the only ones with this problem, everyone from early Corvette to motorcycles to truck guys fight this issue. All opinions seem to recommend using a vented cap on a non vented tank and all have the same issue with pressure building in the tanks because the valves in new caps only vent in one direction. Many people use the drill a hole in the cap method and some add a small vent pipe to the filler neck, I may explore that sometime in the future. My latest modification to the vented cap was to remove the valve and spring completely and drill a small hole. As a word of CAUTION, if your car is kept in the garage you will notice the vented fumes linger in the air, it does in mine to a small degree but my garage isn't well sealed and I have no source of ignition like a pilot light on a water heater etc. I always open the door and let it air out for a few minutes before entering or starting the car. Time for a roof vent I guess.
Finding an OEM cap is a little difficult. I passed on the last on on Ebay, I just couldn't justify in my mind paying that much for an old gas cap and not knowing if the seller is even sure it is correct. I know a guy with with a wagon and ranchero so I'm going to go look at his and see if any of the caps are original..
Not sure what cap I have, but when I fill it gas spills out on turns. We built up the gasket but it still does it, I think I'll dig through my junk and see what I find.
Quote from: Frankenstein57 on 2014-07-08 20:18
Not sure what cap I have, but when I fill it gas spills out on turns. We built up the gasket but it still does it, I think I'll dig through my junk and see what I find.
At a $1.67 a liter for premium I never have enough in the tank for it to slosh out!!!!
Today I dissected my 'vented' gas cap - that I now know only allows air into the tank. I first pulled out the valve and then tested the cap to see if air could still pass through from the inside - and it did. Basically, a 10-second fix and I now have a vented cap. Below are some pics of the style cap and what it looks like blown apart.
(http://i158.photobucket.com/albums/t102/57meteor/cap_01_zps289874ca.jpg) (http://s158.photobucket.com/user/57meteor/media/cap_01_zps289874ca.jpg.html)
(http://i158.photobucket.com/albums/t102/57meteor/cap_02_zps5e057d3a.jpg) (http://s158.photobucket.com/user/57meteor/media/cap_02_zps5e057d3a.jpg.html)
(http://i158.photobucket.com/albums/t102/57meteor/cap_03_zps58b41e55.jpg) (http://s158.photobucket.com/user/57meteor/media/cap_03_zps58b41e55.jpg.html)
(http://i158.photobucket.com/albums/t102/57meteor/cap_04_zpsbe630b24.jpg) (http://s158.photobucket.com/user/57meteor/media/cap_04_zpsbe630b24.jpg.html)
Good! I hope that works, very similar to some of my earlier experiments that had the plastic retainer for the valve. The newest cap I have is similar but the center part that holds the valve is metal rather then plastic. I still couldn't get it to vent pressure, when the gasket is compressed in the tight position the was no way for the air to get out so I still had to drill a small hole. I don't a camera available right now so I had to reuse your photo..
if you read the 1957 ford parts book it says the cars on the wagon frame, the gas caps are vented.the others are not vented
I really liked the looks of these, so I picked up one of these "vented" caps to see if it could be fixed to a non vented..at least to not allow gas to slosh out. I'm gonna put it on my old gas tank that I can put some gas or whatever into and tip it to check for leakage.I'll let you know how that works out.
It leaks...thru the key hole. I don't think there's any way to keep it from leaking, the lock mechanism is pretty much open in the back. Unfortunatly there was no way to tell in the shrinkwrapped packaging. They did say vented, so I can't complain.
I did buy another one at the same time that doesn't even go on the filler neck, and was suppose to be stainless, but is zinc plated.
Rich I hope you don't end up with a cap collection as large as mine and find something that works. If a locking cap leaks that may be just what I need :003:
Vented caps are used to let air into the ever emptying tank so vacuum doesn't collapse it or the lines.
If you open the cap and air rushes in you have a problem.
Goodluck,
Ron.
Quote from: hiball3985 on 2014-08-03 13:36
Rich I hope you don't end up with a cap collection as large as mine and find something that works. If a locking cap leaks that may be just what I need :003:
HaHaaa.....Jim, do you get the feeling we're mentally challenged? You're looking for a cap that is the oposite of what I'm looking for, and well both end up with a collection that doesn't work, LOl. The obvious solution would seem to be you sending me your collection, and I'll send you mine, but there is probably something wrong with that solution I haven't figured out yet.
Actually, I'm just being stubborn. I have seen non-vented nos caps on ebay that would work (I think)...I'm just trying to find a pretty one. I would have thought with all the billet and shiney stuff out there, a gas cap for a 50's car would have been easy find.