First thing that comes to mind are rocker arms, although you said it goes away (?) Chain slap, exhaust manifold leak comes to mind as well if the noise goes away after a bit.

What many Km does the odo read?

Check out these threads:
http://www.peachparts.com/shopforum/showthread.php?threadid=16183&highlight=560+ticking

http://www.peachparts.com/shopforum/showthread.php?threadid=21636&highlight=560+ticking

http://www.peachparts.com/shopforum/showthread.php?threadid=34070&highlight=560+ticking