Which gas tank?

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Ruger64

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I got under my car today.
1971 Valiant Slant/6 Auto
I thought my sender was leaking. But no, my gas tank is leaking at the seam.
I was looking at the website below and got confused. It lists two different tanks. Both 16 gallon.
But it says something about early or late 71.
It says either 4 side vents with EEC,........... or a Front vent pipe?
I don't know which one i have?
Here's the two tanks.

http://www.autopartswarehouse.com/d...acementQQFuel_TankQQ19701971QQREPD670107.html

http://www.autopartswarehouse.com/d...QQSpectraQQFuel_TankQQ19711976QQSPICR11E.html
 
1970Duster said:
Get a gas tank that baffles built inside.
Click to expand...

It didnt say if they had baffles. I am just trying to figure out this vent thing. I looked at my tank...in the car. And I see a hose coming off the top. But I dont see 4 vents like the one is saying. Unless I am misunderstanding something.
 
I don't think 1970 had emissions vent tubes, unless in CA. My 69 didn't, as best I remember. If you have to get a tank with them, you can just plug them off. Those prices look a bit steep. I recall seeing them for <$150 on ebay or rockauto. Many posts on here about manufacturers and quality, so use search.
 
Open your trunk and look for an extra tube on the left rear wheel house this is where the so called vent tubes go to.
 
Okay, I am confused. I did find on ebay "spectra" tanks.
For my 71 Valiant, it does show early/late model.
So 4 vents on the side of the tank "early model",
One vent at the top above the sending unit "late model".
Here's where my problem lays,.
My 1971 Valiant has a used tank in it, that the last guy put in.
It is out of a 69 Dart he told me. Which makes sense.
Okay, there is "no" vent tube on it at all! So I have nothing to go by?
I have no idea which tank to get.
If I get the one with the "one vent tube" at the top of the tank.
Do I just put a rubber vacuum plug on that vent tube? Will that build pressure if not vented?
I just want to make sure. I am ready to order my tank!
 
did you open your trunk, and look at the driver side wheel house? If there's a large tube protruding up through the trunk floor,that has a cap on top, fasten'd to the wheel house, then your car had the tank with the 4 vent tubes on the side. if not then your car did not have it. Most 71 cars have it.
 
fanofpetty said:
did you open your trunk, and look at the driver side wheel house? If there's a large tube protruding up through the trunk floor,that has a cap on top, fasten'd to the wheel house, then your car had the tank with the 4 vent tubes on the side. if not then your car did not have it. Most 71 cars have it.
Click to expand...

Here's a photo, I just ran up and took real quick. I see nothing?
So if mine doesn't call for the 4 vent tubes, then it has to have the one vent tube. Where does it go?
They don't sale one for my 71 with NO vent tube. They called for a 4 vent on the side, or one vent tube on the front of the tank.....I am so confused.
Heres one I found on ebay:
You can see in the one photo on ebay, the third photo, the one vent tube on the front of the tank. 71 had to have a vent tube according to anywhere I want to order. But I don't know what to do with the vent tube, even if its just the ONE on the top.
http://www.ebay.com/itm/230830989977?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

trunk.jpg
 
'71 was when the Feds mandated evaporative emissions canisters or EEC! Instead of venting the tank to the outside the vapors were "stored" in a charcoal canister which sent them to the carb every time you let off the throttle and manifold vacuum increased. Over time the canisters accumulated enough condensed fuel vapor that liquid fuel was sent to the carb and flooded the engine and caused all sorts of problems. When that happened all the lines were plugged and the canister found its way into a dumpster to restore the car to running condition. Either get the '71 tank with 1 vent and plug it or do what the previous owner did and get a '69 tank so you can put things back the way they are with good seams.
 
grumpuscreature said:
'71 was when the Feds mandated evaporative emissions canisters or EEC! Instead of venting the tank to the outside the vapors were "stored" in a charcoal canister which sent them to the carb every time you let off the throttle and manifold vacuum increased. Over time the canisters accumulated enough condensed fuel vapor that liquid fuel was sent to the carb and flooded the engine and caused all sorts of problems. When that happened all the lines were plugged and the canister found its way into a dumpster to restore the car to running condition. Either get the '71 tank with 1 vent and plug it or do what the previous owner did and get a '69 tank so you can put things back the way they are with good seams.
Click to expand...

Well he used the 69 tank out of a used car, that he had on hand.
Thats why he used it., due to the original being rusted......Car Sat for 15 years.
The 69 tank is 18 gallons.
My 71 tank is 16 gallons. Now I know why my gauge was off a bit...ugh!
Okay, I will grab the one vent pipe set up. I didn't know if capping that little vent off would build pressure or anything odd. That was my worry. Sorry for the dumbness. I just didn't want a problem. LOL
 
pre 71 had a vented fill tube. it has a fitting on the tube . There is a line that loops at the top and runs pack down the fill tube through the rubber seal and vents under the car. I put one of these on my 71 to eliminate the 71 impact collision protection tube that every one thinks is a vent system. I have a 100 gal per hr pump. 1/2 inch fuel lines a 1050 carb with a narrowed factory tank to run fake tailpipes and tips. Never creates a vacuum in the tank and never runs out of fuel. You can make your own with a threaded hose nipple. If you nee pics I have every fill tube here for all years and models. Steve
 
grumpuscreature said:
get the '71 tank with 1 vent and plug it.
Click to expand...

I dearly hope you meant to add "and provide a 69/ earlier style vent." You cannot run these with NO vent

The early vent system was simple:

2cmugso.jpg


A representative view of how the early evap emissions system worked. This is out of the '72 manual, which had the surge can in the trunk. Later tanks had this function built into the tank, IE they had an "air trap" box thing inside the tank which took the place of the separate vent can.

IF YOU ARE NOT USING the carbon can system, and IF you don't need to meet any emissions in your area, I'd buy the earliest tank that will fit the car (70?) and implement the 69/ earlier vent pictured. All you need is to braze / weld a 1/4" fitting into the filler neck up high as shown, run a tube up high inside the quarter, "U" turn down along the tube and through the trunk gasket as shown. The vent tube simply "open ended" inside the rear frame rail, probably to prevent damage to the tube, and prevent excessive dripping.

The fill caps on the emissions tanks were a "pressure vacuum" cap. These are NOT meant to be an operational vent. Rather, they are a pair of relief valves, to relieve excessive pressure and vacuum, for safety, and to prevent damage to the tank.

2r2q0ra.jpg


Here's the later (from 74 manual) tank with the liquid/ vapor separator built into the tank. So I guess this would be the "single vent" tank they are talking about

http://www.forabodiesonly.com/mopar/showthread.php?t=194100

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Do you have the charcoal canister still? That would go to that vent at the top of the tank above the fuel gauge. If you don't have the canister, you can run a return line from a fuel filter back to this vent. The '71 gas cap might also be vented.
C
 
I am not home near my pc to look at those photos. There is no canister on the car. So plugging the little vent tube on the tank is not good???
He had this tank from a 69 dart on here with no vent at all. I am so confused. So plugging it off could cause problems?
I have no vent now at all. The gas cap is original. I dont know if the cap is vented or not. Would this be a really bad thing then to plug it? If so. I guess I can rig something up.
 
clhyer said:
Do you have the charcoal canister still? That would go to that vent at the top of the tank above the fuel gauge. If you don't have the canister, you can run a return line from a fuel filter back to this vent. The '71 gas cap might also be vented.
C
Click to expand...

Do you mean to just run a hose off the single vent to the front to an extra fuel filter?
 
Here is the set up on my '72 Duster. It was a basket case, with nothing much but a bare shell when I got it. Fuel line to the pump, pump to this filer:
http://shop.advanceautoparts.com/we...ilter-fram_22660924-p?searchTerm=fuel+filters

The "T" off the filter goes to a return line to the tank, into the small vent nipple above the fuel gauge float. The gas cap is "somewhat" vented. Unless you were sure your cap was vented I wouldn't plug the vent nipple, the tank has to be vented.

I have driven my car for a year now with no issues.
C
 
The vapor return, while a good idea, has nothing to do with a tank vent

There's no such thing as "somewhat vented." The late model "pressure vacuum" caps were NEVER intended to be a "somewhat vent" and can allow the tank to operate under a slight vacuum, which can cause vapor lock !!!! or a slight pressure

Vented cap? I guess if you don't mind fuel all over the side of your car...........................

So please tell my, clhyer, how IS your tank venting? You say "don't plug the vent nipple" OK, if you leave it open (at the tank) it WILL leak.
 
You have asked a very good question, 67Dart273, how is my tank venting? I have described the set up I have. I have driven it the past year without problems, the furthest I have gone was about 2 1/2 hours at about 70-75 mph over most of the trip.
For sure, I don't fill the tank until it is running out the filler pipe, but I've had no issues.
C
 
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