1997 Ford Crown Victoria ENGINE KNOCKING INSIDE THE VAL COV

Is your motoring is for the valves sticking and the push rods falling off of the overhead cam.Mostly if the car has sat for a while or bad gas.It can also be a collapsed lifter stuck due to some trash or dirt in the lifter,If so there are over the counter motor flsh but most of the time its diesel fuel that helps do the job of cleaning engine sludge and dirt out of a motor.Or you could possibly have a bad lifter.Also you might check your oil pressure to see if you have enough pressure to lubricate all the lifters.

Just for giggles, remove the PCV and see if noise goes away.