DO NOT TOUCH THE INJECTORS ROCKER ADJUSTERS YET
If you took it to bits and put it back together again with the injectors in the same holes (I sure hope so because it matters) then the injector rocker adjustment is almost certainly NOT to blame. If they have messed up the injector clearances causing an injector to "bottom-out" each affected injector will probably be destroyed already. If the engine is running on 5 cylinders the injectors would seem to be OK.
Is it a hydraulic cam follower (valve cam follower) not filling with oil and running slack? If so, this USUALLY ceases after 15 or 20 minutes of running at tickover speed. It can make a Hell of a noise ....
Is a piston slapping the underside of the head because a too-thin head gasket was used? That is bad news if it is.
If the valve-timing is WAY out a piston might be smacking a valve, but I doubt if this will have happened.
I think most of us would be thinking along those lines at this stage. Once you find out do let us know.
CharlesY