Posted for "Marko Bewersdorff" <marko@bewersdorff.com>:

How about a ball valve - those with zero flow restriction? You could put one
in line and manually control flow - maybe a remote lever of some sorts -
that would be like a cowl flap basically. hmm, I sound too theoretical - for
the record, I currently have no cooling problems - the engine is still
sitting near the plane on an oil drum, just need to get started on the
engine mount...

re

Marko