[NoVa-Corvairs] Vacuum leak?

[Daniel Goldberg]

So I was rooting around my 'Vair engine the other day and noticed that the plasitic manifold pressure gauge line -- the one that fits into the crossover pipe -- wasn't hooked up.

Seemed to be a pretty good reason why I could have a vacuum leak, so I installed it.  Except that I could only unscrew the little brass coupling -- the nut on the crossover pipe would not budge.  So I threaded the line through the coupling and into the crossover.

Some observations and questions:

1) Idle is certainly less erratic now; however, depending on the car's mood, it still ranges from perfect to way too low.

2) Why can't I unscrew that nut on the crossover pipe?  Is it supposed to unscrew?

3) My manifold pressure gauge now works.  I though the thing was busted, but it works!  Here are typical readings:

a) At full acceleration, 0
b) At partial acceleration (i.e., cruising) -7.5
c) At idle: -15

What's all that mean?  Is it good?

thanks!

daniel