Yes, there is plenty of space for a conventional seal, Would you suggest a bearing like this?
NJ204 Cylindrical Roller Bearing 20x47x14 Cylindrical Bearings
Also, the seal size is 20x47x7 that I am looking at here...
Oil Seals Metric Sizes Table 6 of 26
Which seal design would you suggest? also, Viton or PTFE?
I am going to put this together and run at speed from my lathe, with the tube a 1/3 full of oil just as I found it. Even though I don't know exactly which oil is in the tube, I've a pretty good idea that it is Mobil 625 or 629 gearbox oil.
I don't know yet how to replicate the back and forth motion of the oil in the tube to represent accellerating/decellerating of the the car. I will also will be able measure any deflection at the center of the shaft at max speed of 3500 rpms..