Chris writes:  "Even though the oil temperature gauge might only indicate 180 deg F, the oil is plenty hot to boil off moisture.."

Well, maybe yes, and maybe no.  It may depend upon whether the oil is hydrophobic or hydrophilic, plus there is a time lapse period for the distillation of the water to take place.  Added to that, the cylinders, where the water is actually manufactured by the combustion process, are mostly closed bottles when the engine is at rest, holding the water in the bottles until it does its damage.

Gary Casey is on the right track with a pcv vent idea to remove water from the sump.  The efficiency is the question.

If you take 10 liters of hot 15w50 saturated with say, 30-60 grams of water in an emulsified condition, put it in a 22 liter flask, add stirring, you will probably not get but a few grams of water out of the neck of the flask.

Add vacuum, and a condenser, and you may get most of it out in a half hour.

Add vacuum, condenser, and an inert gas bubbler at the bottom of the sump, and you will get it all out in a few minutes, plus your oil will be absent the oxygen needed  for the rusting process.

But this does not address the water trapped in the cylinders.  Perhaps nothing less than pressurizing the air inlet with inert gas and using it to turn the engine over for a period of time would do the trick.

I do know one thing.  If I had to have an engine in storage for a period of time, I would hook up a dry nitrogen bleed into it, including each cylinder and the crankcase.  Every few weeks, I would rotate the crank.  Since the engine was run at the factory,  I would first drain all remnants of the factory oil, and then replace with clean dry oil for storage.

Some may think this is overkill.  I priced out a modest overhaul on the TSIO-550.  $7-10 K.  A full-blown overhaul for a run-out engine is $30 K.  Maybe not overkill, after all.

David Jones