Hi,

Flying fuel (5% turbine oil mix Kerosene) is best since we have a few O-rings inside the bearing tube and not really sure if some of these corrosive compounds are "rubber" friendly or not.

Storing vertically will minimize "sitting" oil or deposite on bearings. In addition, any unwanted oil/contamination will run out of the engine by gravity.

Storing the engine in a sealed plastic bag is also ideal to prevent rust. Eventhough most parts are made from aluminum, stainless steel, and inconel, the rotor shaft and bearing housings are still made from harden steel.

Enjoy..B777