[Tigrrr]

My Duetto has a locking gas cap on it. I hate carrying around more keys than absolutely necessary, so I'm looking for an original, non-locking gas cap. There's a question I have, though... Was the original gas cap on the Duetto vented or not? I hope this does not seem like a dumb question, but I just want to be sure to get the right type. Thanks a lot!

 

[67duetto]

Mine is not vented, see pic.

 

[67duetto]

The other side of cap. It gives good sucksion when I open and close the cap.

 

[flivesay]

my 68 spider and 68 gtv are not vented

 

[papajam]

The cap should be vented. Note the vent holes in the pic below.

 

[Alleggerita]

That little nipple you see in the middle on the inside of the cap is the vent. Without a vent you will build a vacuum in the tank ...

I see papajam has already posted the appropriate pic before I got to hit the send key ....

 

[Superflow]

Pretty much any pre-1970 car will have a vented gas cap. Anything later will have a charcoal canister with hoses from the tank to the canister.

 

[flivesay]

papjam and alleggerita

I stand corrected. I spoke before I looked. They are indeed vented as papajams pic shows. It makes no sense that they wouldn't be--

 

[Tigrrr]

Thanks for the info...

Thanks a lot for the info. Now, if only I could find one for my car!!! Does no one have one to sell to me? Thanks!

 

[Gordon Raymond]

Good information Superflow. The real answer then is systems with a FACTORY charcoal canister are the SEALED system, those with no canister (again factory built) should be vented, regardless of model year. Good to know.

 

[Tigrrr]

Yup. Good info. Thanks. ...now, anyone have a cap for me?

 

[Superflow]

Thanks! I'm sure those older folks, like me, remember seeing newly filled up big Detroit cars with rear center bumper gas fills, leaving gas stations with 25-30 gallons of gas, with gas spewing out of the gas cap!

 

[Alfajay]

The photo that Papajam posted - reposted below - shows a real Alfa gas cap. You can substitute a generic, aftermarket, universal cap (vented of course) and it will fit sort of OK, but not perfectly. The issue seems to be the width of the "ears" on the inside that fit into the two notches on the filler neck, and then lock as the cap is turned. The universal caps have narrower ears, and just don't lock as securely - at least in my experience.

My point is that you can go to your local NAPA store, and buy a cap like the one pictured below. But, finding a used Alfa cap would be better.