I think xéta- is more likely. [ei] > [ī] only if unstressed, but the sundoma of a basic verb would almost always be stressed.

Nevermind, I checked the old thread and saw that you got xíta- by analogy with cíta. I can’t object to that

+Paul Strack good! :)

BTW, unless you object, I'm adding both of these to Eldamo

Actually, how would the intransitive form be used? I am asking because it is possible the transitive form might simply be used impersonally: xítanen loa Gondoresse “I spent a year in Gondor” vs. (perhaps) xítane lúme ar lá tulenes “An hour passed (lit. passed an hour) and he did not come”

+Paul Strack actually I thought "time passes" lúme xéya as an active verb.

Yes, but an intransitive/transitive pair would generally have the same subject. As in oronyen “I rose” vs. ortanen mánya “I raised my hand”. In this case, time is the subject of the intransitive form but the object of the transitive form.

I feel an impersonal construction is somehow more “Quenya-ish”: xítane lú “passed the time” vs. lú xéyane “time passed”.

I apologize for keeping raising objections, but what about using attested: ᴱQ. lúta- “to have time pass”? The root LU clearly survived, so it could easily remain valid, and its formation and etymology is a lot more straightforward.

So lútane “time passed”, lútane loa “a year passed, (lit.) passed a year” and lútanen loa Gondoresse “I spent a year in Gondor”.

There is also ᴹQ. oi- “to live, pass one’s days”, so alternately oinen loa Gondoresse “I spent a year in Gondor”

I feel SKEY as a root is to clearly connected to the passing of time to be abandoned.
xítane lú feels wrong to me, somehow does not fit into the impersonal constructions.
_lúta- can indeed be a valid alternative/synonym.

+Tamas Ferencz SKEY is a nice root, so I will go ahead and put these in, but I will have to link them to lúta- and oi- as attested alternatives. However, some people may prefer neologisms derived from later roots over attested words from earlier periods, so having the alternatives doesn’t hurt, especially since I think it’s very unlikely we will ever use xéya- or xíta- for any other purpose.