[bulletpruf]

I just installed a new tank in my '68 Lemans; it's the Spectra Premium style for a '69. I put a rubber cap on the vent tube so I need to run a vented cap, but I'm having difficulty finding one that will fit.

Apparently, there are two different types of cap, one shallow (pictured on the right) and one deep (on the left).

I have a deep non-vented cap, but the vented cap that I ordered from Inline Tube is shallow, and it won't work, even with the gasket removed.

Anyone know where I can find a deep style vented cap?

Thanks,

Scott

[tom s]

Scott,remember a vented cap allows air in,NOT out!I had a issue in a non vented tank when the air expanded in the tank and push gas past the needle and seat in my holley and filled a couple cyclinders.Was lucky that the engine locked up and did not fire.Pulled the plugs and it shot gas everywhere.I run that vented cap when driving the car but replace it with one I drilled a small hole in when garaged.My garage faces west and gets very hot in the summer.Someday I will brake down and get a new tank and put a vent in the filler neck.Its a 69 Bird.FWIW,Tom

[bulletpruf]

Originally Posted by tom s

Scott,remember a vented cap allows air in,NOT out!I had a issue in a non vented tank when the air expanded in the tank and push gas past the needle and seat in my holley and filled a couple cyclinders.Was lucky that the engine locked up and did not fire.Pulled the plugs and it shot gas everywhere.I run that vented cap when driving the car but replace it with one I drilled a small hole in when garaged.My garage faces west and gets very hot in the summer.Someday I will brake down and get a new tank and put a vent in the filler neck.Its a 69 Bird.FWIW,Tom

Thanks for the info, Tom.

What would be the problem with me just drilling a small hole in my non-vented cap and calling it good?

Scott

[tom s]

I think a bodies have a vented tank.Tom

[Formulajones]

I ended up finding/buying a couple of NOS vented caps. I found the repop stuff to not work well at all. I can't help but wonder if EPA regulations now keep them from making a new cap properly. Just speculation, but on cars I have a non vented tank on, like my 69Z for example, repop vented caps would not work. Bought an NOS cap and it's been perfect for years. Most likely exact same setup as Tom's 69 Firebird.

[HoovDaddy]

Stant and Moto-Rad Part#10646 will fit and it's vented. Just went through this on my '69. OEM replacements won't fit the Spectra neck.

[bulletpruf]

Originally Posted by HoovDaddy

Stant and Moto-Rad Part#10646 will fit and it's vented. Just went through this on my '69. OEM replacements won't fit the Spectra neck.

Excellent! Thanks for that info!

EDIT - doesn’t look like it will work; I need the deep locking tabs and this one apparently has the shallow ones.

Thank

[srmmmm]

Originally Posted by bulletpruf

Thanks for the info, Tom.

What would be the problem with me just drilling a small hole in my non-vented cap and calling it good?

Scott

My original 1970 Esprit had a rear clip put on it after I took down a telephone pole in Flint, MI from a 1971 model. The fuel tank in the 71 had the expansion tower that rose up behind the rear seat. I had trouble with fuel delivery all the time with it until I drilled a 1/16" hole in the gas cap. Never had any problems after that. Drove it that way for 25 years.

[HoovDaddy]

Originally Posted by bulletpruf

Excellent! Thanks for that info!

EDIT - doesn’t look like it will work; I need the deep locking tabs and this one apparently has the shallow ones.

Thank

I bought 5 different caps last summer including the deep one you describe. None fit the Spectra tank. The deep one wouldn't fit in the hole. I contacted Spectra and they gave me that number for their 1969 GM tanks.

[hgerhardt]

The factory put a separate vent on those A-body tanks for a reason: the filler is so low that under hard acceleration, fuel will come out if the cap were vented. Firebird/Camaros get away with a vented cap as they're mounted higher up.

What was your reason for plugging the factory vent provision?

[tom s]

My 69 bird repo tank leaks gas with the vented cap and gush’s out with the one with the hole in it.Tom

[bulletpruf]

Originally Posted by hgerhardt

The factory put a separate vent on those A-body tanks for a reason: the filler is so low that under hard acceleration, fuel will come out if the cap were vented. Firebird/Camaros get away with a vented cap as they're mounted higher up.

What was your reason for plugging the factory vent provision?

I was looking for a simple solution - no vent and just running a vented cap instead. I just didn't realize that finding the correct vented cap would be somewhat involved.

Thanks

[bulletpruf]

Originally Posted by HoovDaddy

I bought 5 different caps last summer including the deep one you describe. None fit the Spectra tank. The deep one wouldn't fit in the hole. I contacted Spectra and they gave me that number for their 1969 GM tanks.

Ok, I'll give it a shot. If it doesn't work, I don't mind having another spare.

Thanks

[Formulajones]

Originally Posted by tom s

My 69 bird repo tank leaks gas with the vented cap and gush’s out with the one with the hole in it.Tom

Yup even the NOS vented cap I run on the Z will leak a little gas if I fill it completely up and then park on an incline. It'll slowly dribble. But I mean I have to fill it up to the neck. When the car is level it's fine. Pop the clutch it might dribble some, but drive 20 miles and the level is already down enough it doesn't matter. Not a big deal and common fair, based off how all the other classic cars here act similar.

[JUDGE3]

drilled the tiny hole. done.