BMW specs show a nominal free spring height of 46mm(1.811 inches), and requires on inspection that the springs be of the SAME COLOR CODE
, and that the springs are ALL the same height, stand straight, and are square/perpendicular. If one or more is of a different height, you replace them as a set, and not individually.
* the rationale is that valve springs in bimmers are supplied by different manufacturer's and each might differ slightly in height if only to achieve the required spring resistance when the cam lobes push on the valves.
There is no break-in procedure provided for camshaft/rocker arms/lifters/valves, but as in any good shop practice procedure, it is incumbent upon yourself to check that all oil holes and passages are properly cleaned and free of sludge, deposits , or obstruction that might restrict oil flow.
As well, on assembly, a good oiling of all moving parts before installing the valve covers will ensure sufficient lubrication until the crankcase oil circulates through.
** make sure the new head gasket is EXACTLY the same hole-for-hole. I have encountered cases where, in aftermarket gaskets there was a hole missing on a new gasket, and the missing hole just happened to be the oil passage hole