Non-vented gas cap

[monte11sec]

I bought a fuel tank from Original Parts Group (described as 20-gallon/3 vent w/EEC) and had a sump welded to it. The two outer vents were connected back to the original vent connections and the center vent was converted to a -8AN return. I also bought the vented gas cap that OPG sells.

 

The tank and the gas cap can be found at the links below:

 

/// FUEL TANK ///

 

http://www.opgi.com/product.asp?topcatid...&yearrange=

 

/// VENTED GAS CAP ///

 

http://www.opgi.com/product.asp?topcatid...&yearrange=

 

 

I am noticing that I smell gas (after driving the car for a while) if I fill the car beyond 1/2 full. I don't see any signs of fuel leakage around the tank, lines, etc. I think that the problem may have something to do with using a vented gas cap on a vented tank. I have been reading that the rule of thumb is to use a non-vented fuel cap on a vented tank or vice-versa. I have also read that a EEC system will not function correctly if a vented cap is used. I have noticed that fuel will spill out of the vent hoses if I remove the vent hoses from the tank. Should fuel be making it into the vent lines that run towards the back seats?

 

Now to my question........I am trying to find a non-vented fuel cap that will fit the tank that I bought but OPG only sells the vented version. I checked Year-One as well but I couldn't find one either. I would use the cap that came off of the stock fuel tank but it does not fit the aftermarket tank. Has anybody ever run into this problem? Any suggestions on non-vented gas caps?

 

Thanks.

[72MC]

Joe, I basically did the exact same thing as you. I bought a new OE tank, welded in a sump, and used all 3 vents to the cannister. I used the old sending line as a return line and am using and original 72 cap with new rubber in the cap. I have no smell of gas and no problems of any kind. Are you sure the smell is not coming from somewhere else? You also should be able to use a non vented cap since your tank is vented and I would think any universal type non vented cap would work as long as it fit properly. I know they sell a non vented cap for 68-72 C-10. Maybe check with LMC Truck if your not concerned with appearance. - Dave

[502ci]

With your new sump you are obviously using some braided lines I imagine...are your main fuel lines also braided or are they hard lines? The reason I ask is some people have said they can smell the fuel weeping throug their braided lines.

[kc8oye]

a 3 vent with EEC tank should have a NON vented cap.. in fact the caps aren't usually interchangeable.. which might explain why you are smelling gas...

 

[Big Jim]

You can get a non vented gas cap at almost any parts store.

[kc8oye]

jim yes you can.. but the vented and not vented caps are not interchangeable... at least not between years.

 

when I traded leo my original 1972 EEC tank for a 1970 non-vented tank, I had to buy a new gas cap, as the 72 cap didn't fit the 70 tank....

 

[72MC]

Tim, fyi, my non vented c-10 gas cap fits my vented monte gas tank. That's why I recommended looking into the truck gas caps.

 

That being said, my monte has an old, re rubbered gasket vented gas cap on my sumped vented gas tank and I dont smell any gas fumes like monte11sec does. Thats why I was wondering if the fumes were coming from somewhere else. To me a vented gas cap on a vented gas tank means it is just vented one more time, thats all. - Dave

[kc8oye]

teh filler necks are different between EEC and NON-EEC tanks.. putting a vented cap on a non-vented tank could easily create a fuel leak between the cap and neck...

he said it only happens with more then 1/2 tank of gas.. that leads me to think it's a filler cap problem.