The 'other list' you mention would be the Diesel-Vanagon Yahoo group, and
that would be a great place to learn more about restoring or upgrading the
diesel setup:
https://groups.yahoo.com/neo/groups/Diesel-Vanagon/info

Other than the non-funtioning injection pump, you don't say what's wrong
with the current engine. In short, in ascending order of complexity, the
options for a DIY-er include:
a. troubleshooting and repairing the current 1.6NA engine
b. replacing the engine with a larger new or rebuilt engine such as a 1.9NA
or TD
c. replace engine with a VW inline-four gasoline engine
d. full-on conversion to a Subaru or Bostig engine

You'll find lots of info and supportive communities on the abovementioned
Diesel-Vanagon Yahoo group,
the VW Diesel forum
http://www.vwdiesel.net/forum/
and on the Samba
http://www.thesamba.com/vw/forum/viewforum.php?f=20

Good luck!