Walt, the shield doesn't keep dust contamination out of the pilot ball bearing. Best to use sealed bearing (both sides) or at least a seal on one side and shield on other side, with sealed side out towards the clutch side of the flywheel and shield side towards crankshaft. I also pop one of the seals out using a small flat blade jewelers screwdriver and repack the bearing with high temperature grease if I can't buy them that way, then pop the seal back in place.
The ball bearing shown in JSeery's post #2 has a seal on the side that's facing up.
Here is a previous post on pilot bearings that may be beneficial to read and see some of the pictures posted...
https://www.fordbarn.com/forum/showth...earing+bushing