5kcstq screeching distributor

[Wallace White <wallace@remdesign.com>]

I know there was some conversation on this lately, but I didn't catch
the conclusion to it, so...

At cold startup I've been hearing a screeching noise for maybe 30
seconds or so; it's getting longer. The sound is coming from the
distributor, it seems, though I don't know which part of it. Any BTDT's? 

While taking a look at this, I popped off the distributor cap to take a
look at things, which I actually hadn't done since getting the car. The
rotor arm was totally corroded! I didn't know they could get that bad
and still work. Then when I tried to pull the rotor off, the contact end
of it crumbled to dust--but the car would still start afterwards. (Still
makes the screeching.) There must be at least 3/8" of business end of
the rotor gone. I will replace it before driving it again, but is it
really possible that it still work like that? It seems like an awfully
big gap to spark across.

- Wallace
  '87 5kcstq 150k