I have the head from Series II at a well reputed local engine shop. They do fabulous work on a lot of stuff, but have not worked on a 2.25 Rover head before (go figure...). At any rate, I took the head in to get it checked since I had water in my oil come to find out, one of the casting plugs has failed. I am wondering if anyone has any experience with repair or replacement of this filler material. I will probably contact Turner Engineering Monday, but there's a good chance someone here may know the answer. We're not even sure what the material is... It's not magnetic. I am wondering if it's aluminum. It's the first time the shop has seen something like this, and they work on everything from airplane to train engines! The hole is clearing where the water in the oil came from, now I just need to figure out how to seal it.