by Goldenblack440 » 02 Sep 2009 12:28
Hey Burdar - i know a bit about these bastards. I have one on my 73 and i took it off at first and just plugged up the 4 take off vents from the tank. Big mistake. I had all sorts of problems with what i thought was my new TQuad, but it was actually becasue the tank was pressurising! The fuel cap provided such a good seal ( it had no pressure relief like the factory ones) that the rising pressure in side the tank was pushing fuel through the lines and over riding the floats in the carb. I knew there was heaps of pressure (i guessed at least 5-7psi) because there was a huge whoosh of gas whenever i undid the fuel cap. So i had to put this vapour cannister back on. However that didn't solve the problem becasue not only did i not have a charcoal cannister (evaporative purge gas collection), but the evaporative fuel gas line was blocked with rust. So in the end, i connected it all up but had to use a temporary plastic fuel cap with a vent hole in it.
But back to the evap cannister. That rattle you hear is a one way valve. It stops fuel going through it when you over fill the tank. But the design allows gas fumes from the tank into the cannister to be collected/stored and shunted off to the charcoal cannister which is then purged everytime the engine starts. If you want you car original with the Evaporative emmisions equipment then you should run it all. It won't affect performance. But i would say, by now, most charcoal canisters have passed their "Use-By Date".
You can easily braze up the pin hole, but if the whole unit is scaly rusty like mine, its probably like that inside as well. Many other Mopars used this type i think, Darts, Chargers from 72 on, so shouldn't be hard to find a better one at a wrecking yard. Pain to get out though!
