ok ok ok, I'll let you have it, I was a dick about it.
point being this. Lucas is made to increase the viscosity of the oil you are using. Effectively making it more sticky. Because it is thick and because it doesn't contain detergents, it can't free anything that is stuck. The only two things it can do is keep more oil in places where things are loose and increase oil pressure slightly. hydraulics work due to resistance. You can't have flow without resistance, so therefore, the more resistance you have the more pressure you will have with the same amount of flow.
Marvel Mystery oil and Sea Foam are, simply put, just a bottle of detergents. When they get hot, they clean. A stuck lighter or whatever gets stuck because gunk gets in where gunk shouldn't be. It is impossible to remove all of the old oil when you do an oil change, so eventually some of that old oil just turns to gunk and gets in places it shouldn't be. The idea is, the mystery oil breaks up and dissolves that gunk, allowing you to flush that gunk away when you drain the oil. I don't recommend driving around a lot with that mystery oil in there as A) it burns easy, which is why you can put it in a vacuum line and clean your intake and what not with it, as with sea foam. and B) it thins the oil down. Doing the exact opposite that the Lucas does.
Now, with all of that said, I still remain that it isn't a valve or anything as it doesn't A) happen at all of the RPMs and B) doesn't get faster with engine speed. The oil pump, the water pump, the clutch fan, the alternator, the power steering pump, the bearings, the valves, the lifters, the cams, all of that moves faster the faster the engine turns.
So, to the OP, if the noise doesn't get faster then you've got other places you need to look. The information we need first is things like
Does it smoke?
What color is the smoke?
Any recent work done to anything?
When did the noise start?
Describe the noise, we looking at a metal spoon in a big pot or we looking more like a belt in the dryer?
Does it do the noise sitting still just free revving or only while on the road driving?
If you are driving, does it matter what gear you are in?

Start with all of that before you go exploring in parts of the motor you shouldn't be messing with. No offense, but you don't seem to have a whole lot of knowledge when it comes to engine internals. Wouldn't want you do pull it all apart and either not be able to get it back together or worse, break something in the process.

EDIT: holy crap that was a huge post... Cliff notes
apologized.
explained point in regard to lucas and mystery oil
explained point in regard to the noise related to engine speed
layed out questions OP needs to answer before doing any exploitative surgery to car