Gas Tank Pressure, Evap System, and Gas Caps?

[clintonvillian]

So,

Someone gutted the EVAP system on my 71. I put on a vented gas cap when I installed my new tank.

With the new tank, I notice a "whoosh" every time I open the cap. The tank is pressurized from the heat and vapor. I guess the old tank had a leak, because it didn't do this.

So, I have been running new fuel lines, new fuel pump, etc. I noticed when the fuel line was unhooked, the pressure was pushing fuel up the pickup tube and out of the line.

I really don't want to drop the tank until I need to (at which time I will definitely install a check valve and charcoal canister.

Does having the system "pressurized" cause any problems?

 

[clintonvillian]

Also, anyone have any diagrams of the original Evap system?

 

[AC932]

I've got a couple pretty pictures

First one is connections without the separator box, which I didn't realize was an option.

This one shows the charcoal canister and aux tank routing.

And this one shows everything and hurts to look at.

It probably isn't good to have your tank pressurized, or they wouldn't go through the effort to make it not happen. If you're not wheeling or rolling over, just hooking the vent up to a hose that ends above the fuel tank is probably an acceptable temporary (permanent) solution. But then again, I've been very wrong before

If you'd like real pictures too, just ask

 

[Rustytruck]

you added a new tank what did you do with the vent ports on the tank?

 

[clintonvillian]

you added a new tank what did you do with the vent ports on the tank?

They are plugged. Out of my ignorance I assumed vented cap meant both ways...

Looks like easiest option is check valve and vent hose...

 

[clintonvillian]

Is there a repop charcoal canister?