69 Vented or not?
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,720
Likes: 19
From: Manhattan Beach Ca
69 Vented or not?
Got my car back from J&D after getting rear ended and everthing is perfect but they said my vented cap was wrong and put a non vented on. It seems to tight with all the seals. My vented had no seals.
What is the sure way to tell which one I need? My vented cap sure looks like the original.
What is the sure way to tell which one I need? My vented cap sure looks like the original.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Originally Posted by Surfer69
Got my car back from J&D after getting rear ended and everthing is perfect but they said my vented cap was wrong and put a non vented on. It seems to tight with all the seals. My vented had no seals.
What is the sure way to tell which one I need? My vented cap sure looks like the original.
What is the sure way to tell which one I need? My vented cap sure looks like the original.
http://cgi.ebay.com/ebaymotors/1963-...spagenameZWDVW
Last edited by rihwoods; Oct 15, 2005 at 11:17 AM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
My books say '69 was vented but unless u have EVC on drivers side then that fuel tank cap becomes the press relief vlv. And yes they do have sometype of press relief to save the tank but not for normal operation - like in ur application.
BTW would u recommend J&D for a full paint job? Not trying to steal the thread but they do a lot of body work and someone i know recommends them for paint & body. I see them at Pomona swapmeet selling glass and detail parts. Specialize in corvettes and fairly local too. Compare thier prices? Perfect work?
cardo0
BTW would u recommend J&D for a full paint job? Not trying to steal the thread but they do a lot of body work and someone i know recommends them for paint & body. I see them at Pomona swapmeet selling glass and detail parts. Specialize in corvettes and fairly local too. Compare thier prices? Perfect work?
cardo0
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,720
Likes: 19
From: Manhattan Beach Ca
They did a great job matching my red paint. So good I cant tell anywhere. I would recommend them for paint though I noticed one small run spot on my deck lid behind the passenger seat on the vertical flange edge but nobodys perfect.
I'm a little concerned they would recommend me the non vented cap when 69 has vented. They've been in business 20+ years.
I'm a little concerned they would recommend me the non vented cap when 69 has vented. They've been in business 20+ years.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Thx for your feedback/recommendation.
I will have to get an estimate from J&D when its ready to paint.
Non-vented cap is easy mistake. Well sometimes even the expects goof. No 1 knows more 'bout ur car than u.
cardo0
Non-vented cap is easy mistake. Well sometimes even the expects goof. No 1 knows more 'bout ur car than u.
cardo0
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Racer
Joined: May 2004
Posts: 419
Likes: 4
From: MA
What's the difference between a vented and non-vented cap? I was under the impression that the only difference is that the vented ones don't have a gasket and the non-vented ones do. I have the locking gas lid, which I bought used. It came with a gasket, which I assumed would be for 1970 non-vented cars and up, so I removed it. Is this wrong?
Racer
Joined: May 2004
Posts: 419
Likes: 4
From: MA
Originally Posted by rihwoods
Vented con me with gasket...
HERE'S WHAT I SAW:
http://www.ecklers.com/product.asp?p...E4G2G8W99X0R89
THIS IS WHY I WAS THINKING I NEEDED TO REMOVE THE GASKET.
Last edited by cicconjo; Oct 16, 2005 at 08:23 PM.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Typo..meant to say my vented cap came with a gasket...
http://cgi.ebay.com/ebaymotors/1963...sspagenameZWDVW
Don't know dink about the locking caps...
http://cgi.ebay.com/ebaymotors/1963...sspagenameZWDVW
Don't know dink about the locking caps...
Drifting
Joined: Dec 2004
Posts: 1,345
Likes: 3
I've had my '69 since 12Feb76 and it looked to have an original non-vented gas cap. I still have the same gas cap on my car. My car was built on the first day of production, (SN00035), so I'd guess all '69s should have non-vented gas caps. My family has 2 other '69 Corvettes and both have non vented caps.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Ok guys, here's the long story.
None of my numbers book address the EVC sys directly. But all the vendor catalogs sell a vented cap through '69. 1970 is first year for nonvented caps. But really the important item here is the charcoal canister (EVC). On models that have an EVC the tank is unvented and tank vapor press flows through the charcoal and vapor is expected to be retained in charcoal. Ya, right with a 30 yr old canister. 
When the carb pri blades open above a port in the throat the eng vac pulls purge air from a EVC vent by eng vac through that EVC and removes the vapor along with. BTW it takes about 1/2psi tank press for sys to work and the non-vented caps have a relief somewhere near 5psi to hopefully save the tank from overpress - yes u could possibly hear ur own gas cap fart.
So what i'm saying is if u don't have a EVC inside the drivers side fender like on my '74, u should run a vented cap.
cicconjo, i also just bought a locking cap from Ecklers and the instructions say to leave the gasket out to run vented. Or install the gasket to use unvented. I expect it will work ok. Kind'a nice to have the option with one cap. And with gas prices now locking gas caps should be a popular Xmas gift.
cardo0
When the carb pri blades open above a port in the throat the eng vac pulls purge air from a EVC vent by eng vac through that EVC and removes the vapor along with. BTW it takes about 1/2psi tank press for sys to work and the non-vented caps have a relief somewhere near 5psi to hopefully save the tank from overpress - yes u could possibly hear ur own gas cap fart. So what i'm saying is if u don't have a EVC inside the drivers side fender like on my '74, u should run a vented cap.
cicconjo, i also just bought a locking cap from Ecklers and the instructions say to leave the gasket out to run vented. Or install the gasket to use unvented. I expect it will work ok. Kind'a nice to have the option with one cap. And with gas prices now locking gas caps should be a popular Xmas gift.
cardo0
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Vented caps were on all Vettes through 1970 EXCEPT California versions. The CARB smog laws in California brought about closed evaporative emission systems in 1970 for California bound Corvettes (carbon cannister on driver's side of engine compartment below the vacuum tank, sealed fuel filler caps, evaporative fuel vents from the carb float bowls, ect.) DO NOT run your Vette with a non-vented fuel cap, you will have problems!
Team Owner
Joined: Jul 2004
Posts: 40,365
Likes: 787
From: Redondo Beach, California
Would it be OK to use a vented gas cap on all years? Unless it's really needed, it seems using a vented gas cap would be the best way to go. (No backpressure on fuel flow, one less thing to go wrong.....).
Also by the way. You can put 20 gallons into a 68,69,70(?).... Some where along the way, GM started putting a filler tube that extended into the gas tank. This prevented people from completely filling the tank because the extended tube meant there was always air in the top of the tank. Maybe this was a safety concern and maybe it was to prevent people from pumping gas into the vapor return lines. Anyhow tank capacity was reduced by 2 gallons. If your tank has the extended tube, you can get 2 extra gallons of capacity by reverting back to a 68 or 69 filler tube.
Also by the way. You can put 20 gallons into a 68,69,70(?).... Some where along the way, GM started putting a filler tube that extended into the gas tank. This prevented people from completely filling the tank because the extended tube meant there was always air in the top of the tank. Maybe this was a safety concern and maybe it was to prevent people from pumping gas into the vapor return lines. Anyhow tank capacity was reduced by 2 gallons. If your tank has the extended tube, you can get 2 extra gallons of capacity by reverting back to a 68 or 69 filler tube.