I'm file fitting a set of Mahle rings today. There are 2 distinctly different colors of rings. I believe one is moly coated ductile iron and the other is cast iron. Which color is the top and which color is the bottom? Is the coated one the darker of the two?
Ok,, most companies package the ring to show "top" and "2nd", but that isn't always the case. Most rings will have "dots" on the top, or the instructions will show which way they go in. You will notice a very distinct difference in hardness when you file the rings, I suggest doing the darker iron 2nd rings first, since they are softer and require less work to file. That way you don't get used to the amount of work it takes to cut the moly top ring, and then get over zealous and cut too much off the iron rings before you realize what you have done.