Some time ago, was wondering what oils to use in an Aurelia. Part of the issue is that the newer oils operate a bit differently than the older ones, and sometimes viscosity changes (say 10w or so) is needed to maintain the same feeling. But another issue emerged - that is, Lancia changed their oil recommendations over the lifespan of the Aurelia. While this might have to do with design changes to parts, it seemed more likely that the original 1950 oil standards dated from before the war, and that throughout the 1950s, oil technology improved as well as experience with long runs of high speed driving (expressways). This became somewhat more clear with the attached summary sheet of oil recommendations over the lifespan of the Aurelia.
Mind you, none of this tells you what to use in the Ardea or the Aprilia - do you go original, or updated Lancia specs (like the later Aurelia) or contemporary? I tend to run 30W in the top, and 90w (straight) in the bottom, but have heard of someone who uses grease in the bottom.
