Circlips on valves

[LanciaFin]

From parts book and repair manual I've learned, that there should be circlips on valves in their lower grooves. My engine has had its head gaskets changed (by real incompetent mechanics, I might add), and it didn't have these circlips. I'm searching for substitutes, but what are they for anyway? They don't seem to attach anything.

[Hein Reedijk]

As far as I can see, they are meant to prevent the valves form falling out of the head, while working on the head with the valve springs removed. You can leave them out, as I did. No problem.