Possibly. The line is very feint, but it is also quite uneven. Surely if it is a casting mark then it would be straight rather than wavy?
Not 100% sure - you'll need to remove the BB to look from the inside...
I did a quick google image search for "sand casting parting lines" which was pretty fruitless, but it did return this image of a rather rough and wavy looking split line.....
Not 100% sure - you'll need to remove the BB to look from the inside...
I did a quick google image search for "sand casting parting lines" which was pretty fruitless, but it did return this image of a rather rough and wavy looking split line.....