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I’ve had this pop open gas cap for about 10 years. Just got my Shelby decal today so I took it out of the box and installed it. Looks great. Evidently that is all the gas cap is intended to do, look good.




 

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... because they tend to open under the slightest collision, allowing gas to eject out the filler tube.
 
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Most come with a standard gas cap that fits under it instead of using the spring loaded seal to close the tank. I tried the pop open first but it didn’t seal tightly enough and you could smell the fumes. Modern fuel has a much lower vapor pressure than the gas sold in the 60s. It’s designed to work in tightly sealed tanks.
 
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It's all driven by lawyers. The pop-off cap was pretty common. The only way they can sell you the functional pop-off components is if they warn you they are not to be used on the street. Yes, if smashed in a rear end collision there is a possibility of a fuel leak. But then any car with a rear-mounted gas cap has this vulnerability. No car is built today with a rear gas cap. Millions of cars, back in the day, had the gas cap behind the license plate. If you like the pop-off function, use it. I have to think if you get your pop-off cap smashed, you'll have problems other than the gas cap.
 
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I've used the pop off cap for many years and my father for many years before that going back to '67 when he bought the car. No issues. Lawyer stuff and companies practicing CYA.
As 22GT has stated here and elsewhere, if you're in a rear end collision, these cars do NOT become instant firebombs and you've probably got other things to worry about anyways.
 
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Discussion Starter #6
Most come with a standard gas cap that fits under it instead of using the spring loaded seal to close the tank. I tried the pop open first but it didn’t seal tightly enough and you could smell the fumes. Modern fuel has a much lower vapor pressure than the gas sold in the 60s. It’s designed to work in tightly sealed tanks.
That's what I'll do, use a twist on cap under the pop open cap... Thanks
 
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There was a lawsuit (or two or three) back in the 80's.. Then, Ford discontinued the caps for awhile, and then reintroduced them under different part #'s with the inards removed, and a traditional cap included instead. The aftermarket follow-suit, but usually also gave you the inards (disassembled) inside the package, so you could go whichever way you preferred.

Bottom-line, nowadays, the pop-open gas cap is considered a "hazardous" design, so the aftermarket has to include CYA language with the cap.

All of mine in my collection are still as-original. If I get rear-ended, I'll have to sue myself. :)
 

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Discussion Starter #8
There was a lawsuit (or two or three) back in the 80's.. Then, Ford discontinued the caps for awhile, and then reintroduced them under different part #'s with the inards removed, and a traditional cap included instead. The aftermarket follow-suit, but usually also gave you the inards (disassembled) inside the package, so you could go whichever way you preferred.

Bottom-line, nowadays, the pop-open gas cap is considered a "hazardous" design, so the aftermarket has to include CYA language with the cap.

All of mine in my collection are still as-original. If I get rear-ended, I'll have to sue myself. :)
I was actually checking out the standard cap on your website earlier. It says it may or may not have ears, seems like the one with ears wouldn't fit under the pop open cap. I've been thinking about making a trip to Charlotte, I need to pick up some other items so I can check it out when I visit. Thanks
 

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I've knew about a mustang hood ornament, but this is the first time I learned of a mustang TRUNK ornament! :unsure:
 

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I was actually checking out the standard cap on your website earlier. It says it may or may not have ears, seems like the one with ears wouldn't fit under the pop open cap. I've been thinking about making a trip to Charlotte, I need to pick up some other items so I can check it out when I visit. Thanks
When you remove the spring loaded part, the ears fit fine. At least with the caps they include with the kits.
 
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There was a lawsuit (or two or three) back in the 80's.. Then, Ford discontinued the caps for awhile, and then reintroduced them under different part #'s with the inards removed, and a traditional cap included instead. The aftermarket follow-suit, but usually also gave you the inards (disassembled) inside the package, so you could go whichever way you preferred.

Bottom-line, nowadays, the pop-open gas cap is considered a "hazardous" design, so the aftermarket has to include CYA language with the cap.

All of mine in my collection are still as-original. If I get rear-ended, I'll have to sue myself. :)
Rick, do you have issues with gas fumes. I could never get the cap to seal tight enough to keep it from smelling and losing gas to evaporation, so I switch to the hidden screw on cap.
 

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Rick, do you have issues with gas fumes. I could never get the cap to seal tight enough to keep it from smelling and losing gas to evaporation, so I switch to the hidden screw on cap.
I don't have those issues, all my pop-open caps seal as-designed, but then again, they are all NOS caps from the "pre-legal-wranglings" era. I'm not running any repro pop-open caps, but you would hope they would seal properly. Toss reproduction filler necks into the equation, and there are plenty of variables to consider.

Rick
NPD
 
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