Adjusting the valves may or may not be necessary. You won't know until you check them.

This is an easy process involving a set of feelers gauges and rotating the engine until the cam lobe is nearly opposite the follower on the valve you are currently checking. The specs are readily available but my Bentley's is in the garage; memory tells me .014-.016" cold.

If they are a little loose (couple of thousands over) I don't worry about them. If they are a couple under (tight) I will probably swap in a shim to loosen them up a bit.

I adjust mine when I am changing the timing belt. I simply remove the cam after deciding what adjustments need to be made and adjust those in need. I have used the tool designed for the procedure with the cam in place and I find it to be a real PITA.

When removing or reinstalling the cam it is important to loosen/tighten the nuts a little at a time so as not to put an uneven load on the cam (possibly breaking it). This is talked about in the FAQ's.

I wouldn't worry about adjusting the valves until you see if they are out of specs. My experience is that the red block Volvo engines seldom need adjustment if the valve train has a goodly number of miles on it.

Randy