Thanks for the replies. As I say, the ticking goes away after the engine runs for several minutes. I don't know if injectors would quiet down or not.

I found two possible sources of ticking, the two mentioned by the first two replies. Klaus' suggestion, I believe, is consistent with the oil sump o-ring issue I saw reported elsewhere, in that some have said the lifters are initially starved of oil.

Here is a link that has comments about both.
http://www.matthewsvolvosite.com/forums/viewtopic.php?p=20460

The oil sump o-ring job sounds like a pain in the neck. I wanted to fix this before selling the car, but may sell as is.