I'm sorry, but I don't know from what material these rings are made. They were just recommended by someone that I trust and respect. If I had a set in my hands, I could recognize if they are cast iron. Cast iron rings have a grey color to them. It seems like I remember a post here that indicated that they are a steel ring of some sort.

I will be using a set in my 240D engine when it goes back together. The engine only had about 153,000 miles after the rebuild before I had bottom end problems which necessitated disassembly. The cylinders are still beautiful with crosshatch still showing in every portion of all cylinders. If the Goetze rings prove to be cast iron, I will put the engine back together without honing the cylinders.

Not honing the cylinders for any ring is against conventional thinking, but has been scientifically proven effective by Ryder laboratories. I have used this method on several engine rebuilds over the years with tremendous success.

This probably doesn't matter because I will be surprised if these are cast iron rings, so I will end up honing the cylinders.

Since your cylinders are in spec, I expect your overhaul to produce satisfactory results.

Good luck,