Sounds like Vanos. One way to check to isolate the sound would be to use a long handled screwdriver or a stethoscope. Put it around the valvecover areas, particularly near the oil cap, or front area where the units are located. If the sounds is "loud", or louder than other areas on the valvecover than it is likely suspect.
Oh, I forgot to add, if you have not used the screwdriver method before -> to lightly put your ear on the end of the screwdriver to listen.