Hey Guest!
The Viton seal is intended to be used with the original crank scroll intact (but would probably still work OK without it).
After thinking about it, and checking the photo in the instructions; I take that back. The lip seal rides on the smooth surface just behind the scroll, which was originally machined to the same diameter as the scroll. Most likely, when the shop machines off the scroll, they will take that area off as well.(but would probably still work OK without it).
Doesn't sound right. What measurements did you get? The mandrel should be 2.818", while the old crank I just checked is 2.812 (give or take a few tenths)
When you say "machined end", do you mean the scroll area? The Viton seal is intended to be used with the original crank scroll intact (but would probably still work OK without it).