I'm kinda interested in this thread too, I have a 92 Jap mini which most times, not always, makes a ticking noise like it has a wide valve clearance when you start it cold. Usually takes about 30secs to 1 minute to start, then goes away after about another minute. I have set all the gaps as per Haynes. Occasionally though, it doesn't do it all. I plan on trying coopermans feeler trick to find out which one it is. Once the car starts to warm up, it stays away completely until it's cold again.
With the rocker cover off and the engine idling, should there be visible oil trickling from anywhere - I don't really understand how this area is fed with oil?