1985 120hp mercruiser 2.5L crankshaft

Hi I'm new to this forum and look for some info, I'm replacing the rear main seal a 1985 mercruiser 120 2.5l( iron duke)and when I took the main bearing cap off I noticed on the edge of the thin disk shaped diameter between the bearing and seal there's a small ding. This diameter doesn't look to come in contact with the rear seal but just to put my mind at ease I'd like to know what this disk shaped diameter does. The bearing cap has slit in it that lines up with it looks like to let oil drain down into the pan. I was thinking maybe this is used as kind of a splash guard for the seal or something I really have no idea. Any info would be appreciated thanks.

I think the proper term is "Oil Slinger", it keeps oil from directly getting to the seal area..
Bert

Thanks Bert thats what we were thinking but weren't sure. I appreciate the info it's really nice having a place like this to ask questions