I am in the process of giving a cylinder head a refresh after finding a water leak into one cylinder. This post is not about the water leak but valve seals. I have found a type of seal on the inlet valves that I have not seen before (See picture). They are a metal cylinder with a plastic insert. They are apparently held in place by a flange on the bottom of the metal cylinder engaging a groove in the guide. So they are a bit like the rubber 'top-hat' with spring type. I bought four of the latter for the inlet valves, but I can't see how to get the existing ones off and if I were to get them off, I don't know whether the groove in the guides is of a suitable specification to retain the rubber 'top-hats'.
Can anyone shed some light on:
1) whether the metal cylinder with plastic insert type of seal is effective
2) how to get them off, and
3) whether the groove in the guide is likely to be suitable to retain rubber 'top-hat' seal (position, depth, width).
I would appreciate your guidance.
BTW, you will see that one of the stems in the picture has a black plastic washer on it. Oddly, each inlet valve had one of these on it as well as the above-mentioned seal AND a rubber O-ring!
Don