There is an oil additive made by Power Punch that increases the adhe-
sion of oil greatly.  It will not prevent it from flowing into tight
spaces (within reason) and does not decrease lubricity.  It can be used
full strength in gear boxes that are not subject to cold temperatures.
It might be a good choice for these old motors.

There are also very sticky oils made for bicycle and motorcycle chains
that flow very little.  They have a volatile base that allows penetra-
tion and evaporates leaving a sticky oil behind.  Both types of oil
seem (by feel only) to be possibly based on the same ingredient.  The
main thing, however, is to not use too much oil and make sure the
wicking is clean so it will hold the oil.

Spencer Chase