'71 Vented Locking Fuel Cap

[Ray K.]

Concerned about having my original '71 vented fuel cap stolen at future shows and/or events . . .
Does anyone anyone have any recommendations as where to purchase a "quality" reproduction (ex: Zip Corvette?)
Or better yet, does anyone know if GM ever offered a service vented fuel cap?
If so, I'd prefer to purchase one. Any idea where I might find one?

Appreciate any / all insight . .
Thanks.
Ray K (43777)

[Leif A.]

Re: '71 Vented Locking Fuel Cap

Ray,
Available from Corvette Central. It has a rubber seal but they sell the cork gasket as well as the "open slowly caution" decal.

https://www.corvettecentral.com/1970-1974-gas-cap-363232?returnurl=%2fsearch%3fcurrentsearchcategoryid%3d%26q%3dgas%2bcap%26count%3d18

[Michael G.]

Re: '71 Vented Locking Fuel Cap

Ray. You should be looking for a non-vented (sealed) cap.

[Edward J.]

Re: '71 Vented Locking Fuel Cap

Ray, you should be able to find a Stant cap at your local auto parts.

[Ray K.]

Re: '71 Vented Locking Fuel Cap

Mike,
I'm a little confused between the vented and non-vented caps . . .

Zip Corvette shows that the cap is vented for the 1963 thru 1974 model years (# x-206-2)
Corvette Central offers two caps:
- a vented cap for the 1963 thru 1969 model years (#102020)
- a non-vented cap for the 1970 thru 1974 model years (#103030)

Can you help me understand the difference between a vented and non-vented cap?
And, any idea why Zip would offer an "incorrect" cap for the 1970 thru 1974 model years?

Ray

[Patrick H.]

Re: '71 Vented Locking Fuel Cap

Ray,

The fuel tanks changed in 1970, thus the change in cap.

CC is correct, Zip is not.
You're welcome to call Zip and see why they got it wrong.

I run a replacement cap on my 72 when it's not at shows as well.

[Michael G.]

Re: '71 Vented Locking Fuel Cap

As Patrick explained, the 71 fuel system was a sealed system that captured vapors instead of venting to the atmosphere.

[Leif A.]

Re: '71 Vented Locking Fuel Cap

As Patrick explained, the 71 fuel system was a sealed system that captured vapors instead of venting to the atmosphere.

Michael,
I thought the cap was changed from vented to non-vented because the fuel tank became vented in 1970, thereby eliminating the need for a vented gas cap.

[Michael G.]

Re: '71 Vented Locking Fuel Cap

I am not as versed as others here but to my knowledge, the 71 system has an additional line from the tank to a charcoal canister up front that processes the vapors. Thus the system is sealed to allow it to function. This line and canister are probably the venting to which you mention. It would be defeated if allowed to vent through the cap. Hopefully others will elaborate or correct my comment.

[Joe L.]

Re: '71 Vented Locking Fuel Cap

I am not as versed as others here but to my knowledge, the 71 system has an additional line from the tank to a charcoal canister up front that processes the vapors. Thus the system is sealed to allow it to function. This line and canister are probably the venting to which you mention. It would be defeated if allowed to vent through the cap. Hopefully others will elaborate or correct my comment.

Michael------


Yes, 1971 was equipped with EEC. However, all 1970-74 fuel tanks included an integral pressure-vacuum valve. This valve obviated the need for a vented fuel cap and, thus, all 1970-74 caps were sealed. 1970-71 caps had "scalloped" perimeters while original 72-74 caps had a smooth perimeter.

Locking caps were once available for both 1963-69 vented caps as well as 1970-74 sealed caps. The locking sealed cap was GM #3994340 and has been discontinued for many years.

[Michael G.]

Re: '71 Vented Locking Fuel Cap

Thank you Joe. Grateful as always.

[Mark E.]

Re: '71 Vented Locking Fuel Cap

Michael------


Yes, 1971 was equipped with EEC. However, all 1970-74 fuel tanks included an integral pressure-vacuum valve. This valve obviated the need for a vented fuel cap and, thus, all 1970-74 caps were sealed. 1970-71 caps had "scalloped" perimeters while original 72-74 caps had a smooth perimeter.

Locking caps were once available for both 1963-69 vented caps as well as 1970-74 sealed caps. The locking sealed cap was GM #3994340 and has been discontinued for many years.

Do all 1970 cars have a sealed cap? Or only those NA9 equipped (CA EEC)?

[Joe L.]

Re: '71 Vented Locking Fuel Cap

Do all 1970 cars have a sealed cap? Or only those NA9 equipped (CA EEC)?

Mark------


All 1970's were originally equipped with a sealed cap regardless of whether also equipped with NA9. That's because all 1970 fuel tanks were equipped with integral pressure-vacuum valves.

As a matter of fact, late 1969's could have been equipped with sealed caps because late 1969's (like mine) were originally equipped with fuel tanks with the integral pressure-vacuum valve. However, as far as I know, none were originally supplied with sealed caps.

[Ray K.]

Re: '71 Vented Locking Fuel Cap

Many, many thanks to all who responded to my request.
Once again, a "wealth" of knowledge that can't be found anywhere else!
Ray

[Mark E.]

Re: '71 Vented Locking Fuel Cap

Mark------


All 1970's were originally equipped with a sealed cap regardless of whether also equipped with NA9. That's because all 1970 fuel tanks were equipped with integral pressure-vacuum valves.

As a matter of fact, late 1969's could have been equipped with sealed caps because late 1969's (like mine) were originally equipped with fuel tanks with the integral pressure-vacuum valve. However, as far as I know, none were originally supplied with sealed caps.

Thanks Joe.