Author Topic: Original vented gas cap  (Read 4033 times)

GaryL

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Original vented gas cap
« on: December 24, 2005, 08:39:58 PM »
It has taken me a while to get my DZ to idle correctly. Yesterday I got some gas and the tank was pressurized. Is a vented gas cap supposed to hold any pressure? If it holds pressure could that affect how the car runs?
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

JohnZ

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Re: Original vented gas cap
« Reply #1 on: December 25, 2005, 05:58:43 PM »
Yes, the "vented" cap has a pressure/vacuum valve in it, and if the tank hasn't reached the threshold for the valve, it will "hiss" when you remove the cap to refuel.  :)
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william1

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Re: Original vented gas cap
« Reply #2 on: October 05, 2009, 06:10:52 PM »
http://www.camaros.org/forum/index.php?topic=239.0

 vented gas cap, johnz how much pressure are we talking about, i have looked and looked but can't put my finger on it, i think but not sure,, i'm having the same problem, as soon as i bleed off the tank it accelerates fine, the tank was replaced before i got the car so i have no idea if it might be a issue with that,, was just wonderin,,, have a new cap coming....

JohnZ

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Re: Original vented gas cap
« Reply #3 on: October 05, 2009, 10:57:52 PM »
http://www.camaros.org/forum/index.php?topic=239.0

 vented gas cap, johnz how much pressure are we talking about, i have looked and looked but can't put my finger on it, i think but not sure,, i'm having the same problem, as soon as i bleed off the tank it accelerates fine, the tank was replaced before i got the car so i have no idea if it might be a issue with that,, was just wonderin,,, have a new cap coming....

I don't have the specs for the valve in the cap, but my original worked fine until it started leaking, and I replaced it with a reproduction about six years ago, and that works fine too.
'69 Z/28
Fathom Green
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sixt9x33rs

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Re: Original vented gas cap
« Reply #4 on: October 09, 2009, 01:48:02 AM »
My cap seems to hold a lot of pressure. When I take it off just seems to pop to hard. I dont recall having this issue with the original tank.

John Z would a tank change have anything to do with the pressure at the cap?

Thanks :)
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

JohnZ

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Re: Original vented gas cap
« Reply #5 on: October 09, 2009, 03:49:36 PM »
My cap seems to hold a lot of pressure. When I take it off just seems to pop to hard. I dont recall having this issue with the original tank.

John Z would a tank change have anything to do with the pressure at the cap?

Thanks :)

Nope, the tank change wouldn't affect it - but a cap change might.
'69 Z/28
Fathom Green
CRG

jdv69z

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Re: Original vented gas cap
« Reply #6 on: October 09, 2009, 07:12:52 PM »
Yes, the "vented" cap has a pressure/vacuum valve in it, and if the tank hasn't reached the threshold for the valve, it will "hiss" when you remove the cap to refuel.  :)

My cap's original, and works  just as John describes when I refuel

Jimmy V.
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sixt9x33rs

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Re: Original vented gas cap
« Reply #7 on: October 10, 2009, 02:15:15 AM »
I have not changed the cap. I will check again to see if I have the same issue.
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles