if the lifters are hydraulic, then valves revert to closed once oil pressure is gone. so...if it's not running. All rockers should be sitting at the same angle.
If this is the case, how does an engine ever start before it has oil pressure? :D
The valves still open (just not all the way) and some of the rockers will be at different heights while not running. (trust me)
The oil allows the lifters to pump up to full opening and automatically sets the lash once it fills them.
Point is, he just needs to turn the engine to get the lifters off the cam lobes then adjust the preload.
This is probably why the adjuster is way out and still tight.
