[Roadsters] "sealed" fuel system questions

[John F Sandhoff]

> What exactly is that little "valve" for right behind the rear carb on my
> 70 1600 & 2000? How does it work?

Controls fuel return to the tank. Helps prevent vapor locking in hot
weather by allowing the fuel to circulate.

> Can I remove the this valve, the fuel vapor return line and the trunk
> tank and not affect how the engine runs?

Why would you want to? Nissan added these pieces to solve a problem
(vapor locking).

> How important is it to have the gas cap seal correctly on these
> sealed systems?

A sealed gas cap is part of the emissions control. It shouldn't affect
anything, except cutting down on the release of a bit of smog-causing
volatile organic compounds.

===

Here's my general rule: except for a few distinct pieces added because
of regulations (retarded ignition timing comes to mind), the "extra"
pieces that Nissan added were done for a reason. They didn't add
that extra plumbing for the return fuel line (or the water line in the
intake manifold) just because they wanted to increase the expense
of building the car. Every part is there for a reason. Not _always_ a
good reason (fan clutch) but in my view, always figure out why it's
there, before taking it off.

My opinion, obviously.... and not meant to be taken as a scolding :-)  

-- John
     John F Sandhoff   sandhoff at csus.edu   Sacramento, CA