[Dave at Pelican Parts]

Some of the combustion byproducts that make their way into the oil are acidic. Moreover, moisture will get into your combustion chambers and cylinders, and without any oil on the cylinder walls they will start to rust. The oil is put there when you run the motor, but eventually runs off.

Fresh oil won't be acidic. However, you'll still have the oil running off of the cylinder walls and other wear surfaces. I would let the motor run until the oil gets up to operating temp about once per month. (At a guess, about 20 minutes.) It would be preferable to drive the car at that time, but it is often not practical to do that. If you can't get to the car to start it during its down-time, that can be dealt with but it isn't as good.

Just make sure all of the fluids--oil and brake fluid most especially--are fresh before storage. And it may even be a good idea to change them again at the end of storage...

--DD