Ovens seem to work fine for me. The aluminum case expands more than the steel bearings do, so I put the case nose up on a cookie tray and wait till I hear the "thunk" of the rear bearing falling out. The front can then be removed with a dowel.

To reinstall the rear bearing, the case should again be heated in the oven. This time the bearing will be at room temperature so it'll be an even looser fit into the hot case. Use the shaft as an installation tool.

In any case, heating the case is especially necessary for racing and combat engines, where there is a strong interference fit between the case and the rear bearing.

Iskandar