Vented or sealed fuel tank cap

[TURBOPOWERED68]

As most of you guys have seen I have a complete 86-87 set up on my car including the Fuel tank.

The question is born from the Chevelles having the fuel spilling out of the gas cap on hard acceleration and when going up steep hills.

On my car I put a GN fuel tank but I had to Cut a piece off the filler neck and replace it with a hose. And because of the new angle it has I think I will have the fuel out of the gas cap issue.

So if I put a sealed gas cap on, what possible effects could it have on the car?

Here is exactly what’s on the car.

1-GN gas tank- the neck was cut and rerouted with a hose with original GN cap.
2-Fuel vacuum canister-but from an N/A Monte it has NO electrical connections just two vacuum lines one to the fuel tank and one to the engine.
3-on the vacuum line to engine I put a one way check valve to avoid loosing boost pressure into the canister.

So let me know what you guys think about using a
Vented or sealed fuel tank cap?

 

[turbo nasty]

Sealed cause the tank has a vent that goes to teh vapor canistr

 

[TURBOPOWERED68]

Sealed cause the tank has a vent that goes to teh vapor canistr

I am asking because the GN OE gas cap IS VENTED.
So the extra fuel fumes into the canister and eventually the engine shouldn’t be of any concern?

 

[jhanson1750]

VENTED!!! A sealed one can run into a vacume situation in the tank which is bad for the pump, and motor. If the canister is plumbed incorrectly (could happen) you can fight it for a long time. Jon

 

[TURBOPOWERED68]

What IF I disconnect the vacuum line from the Fumes canister?
that wouldn't let a vacuum build up in the tank and the cap can still be sealed.

 

[TURBOPOWERED68]

Ttt

 

[Chuck Leeper]

"I am asking because the GN OE gas cap IS VENTED"
NOPE. The gas cap integrity is part of the smog testing, and must not leak on a vac test. The tank is vented as already stated.. thru the cannister.

 

[TURBOPOWERED68]

"I am asking because the GN OE gas cap IS VENTED"
NOPE. The gas cap integrity is part of the smog testing, and must not leak on a vac test. The tank is vented as already stated.. thru the cannister.

I guess I have a bad Cap

Because I could blow and suck air through the cap.

Time to run to parts store.

thanks chuck

 

[Scarab]

I guess I have a bad Cap

Because I could blow and suck air through the cap.

Time to run to parts store.

thanks chuck

I want your cap. I cant do that on my cap. I need a cap that vents pressure and vaccum