The FSM states for piston rings to place the "punchmark side up" unless a punchmark is not present, then they can go in either side up.
I have a set of OEM Style ITM rings, that do not have punch marks, but they have Letters Stamped on them. I cannot find any instructions or documentation for ITM rings, so I wanted to ask here.
Is it safe to assume to place these rings stamped side up?
One ring looks to be a torsional type (small chamfer on inside upper edge)
the 2nd ring looks square upon inspection, with no chamfer
EDIT: This mahle youtube video says with basically all brands, any punch or mark would indicate the top side. But just wanted to check here as well
https://www.youtube.com/watch?v=QloJ3kjsAyY