OK, this isn't specifically about 993s, but it's is a fascinating video about how plain bearings work in a car/bike and how oil gets around them. And it's not done by your oil pump!
https://www.youtube.com/watch?v=eLP70N8KPSI
Apols if I'm off topic but I had to share it.
https://www.youtube.com/watch?v=eLP70N8KPSI
Apols if I'm off topic but I had to share it.