TR6 Evaporative loss system modification

[Ribbs]

I'm currently running brake and fuel lines on my new Ratco frame for my 1973 TR6 undergoing a frame off restoration. I'm debating about deleting the evaporative line (fuel tank to carbon cannister) at this time. I realize the fuel tank needs to breath, but is there a better way? I was also considering using the opportunity to delete the carbon cannister and associated emissions piping at the carburetors altogether, but then what to do with the crankcase ventilation (off of the valve cover) and fuel tank vent? Maybe it's not worth changing/modifying things?

 

[poolboy]

The carbs are doing the sucking, so everything from the valve cover and CC go in their direction.
In other words you can do what you want with the carbon canister as long as you still utilize the carbs to relieve crankcase pressure via th hose from the valve cover.
As you say the fuel tank at the very least needs a vent, but what you do with the CC will depend upon whether or not you feel the fuel tank vapors from the vent need absorption and deodorizing.
I just strapped a motorcycle CC to the frame under the boot and attached the fuel tank vent to an inlet.... I did without a CC for a long time, but I thought I was smelling vapors so I came up with that...Turns out what I was smelling was coming from a fuel line, not the vent.

 

[Madflyer]

Yes poolboy right I did my frame off, carb take care of the motor I caped the line on the tank and there is a hole in the fuel filler cap I do not need smog so all that is gone ( 1973 TR 6 ) Also any wires for the same are gone. Madflyer

 

[Ribbs]

Do you ever smell fuel vapors using a vented cap Madflyer?

 

[ed_h]

You need to preserve a path from the tank to the atmosphere to both let air in and out, depending on conditions. Without a charcoal canister, you can just leave the tank vent open, but this can sometimes cause a fuel smell near the car.

One solution is a two way vent valve that closes off the tank until vacuum or pressure exceeds a certain level, at which point the valve "burps" the tank.

Ed

 

[Madflyer]

No smell either while parked in the garage or on the road. As my top is almost always down and I park it with a mostly full tank year around. Your tank must be vented or fuel pump will fight a vacuum in the tank. If you look at your cap there is a small oval hole and the rubber seal has the same hole. Unless you spill fuel it is vented to vacuum it does not seem to emit fumes, Madflyer