Oil pump problems

I have the following case with a 250XL Mod.98 pickup

it turns out to have a noise on the head of the right side when uncovering the tapas, it was observed that only the head on the left side is raising the oil while the right does not climb and the noise is a pounding.

(recently both heads were rectified, planning, change of caps Calibration of valves etc) It is worth mentioning that it was only rectified of heads since the change of packaging was made because it was consuming oil (there is no repair in the engine)

and when installing them it worked correctly and after 200mks routes I present this detail ... could help me if it is the problem of the pump or what can it be? I will be appreciated by
the witness light and indicator of the pressure on the board mark that everything is fine ...

I need to know that machine brings the 250xl but if it is a 3.8 V-6 the pump is integrated to the distribution cover and only the replacement is changed but for what I mention that only one side does not have lubrication then it is likely that the metals of the tree have turned and this obstructs the duct that polerisses up the oil

Thanks for the answer ... it is a 4.6lts 8cil engine, I am not very sure if the pump is located on the internal part of the carter and referring to what you mention of the camshaft metals what would be the action to be taken if applicable?

Friend Jose Juan, for what I think, what could have happened is that a slight tree bearing was revolved. The oil pump I do not think it has problems because you say that there is pressure on the other side, it is very rare to pass but I create that I have seen the same case several times ... Now, the cylinder head or head does not believe because it has nothing to do with lubrication. Anyway I will consult with some manuals and I tell you but I thank you for informed.

How about Jrosacol! Thanks for the comment.

Today, what I did was to blow the head in the part where the oil rises, it changes filter and oil and when starting it, observe that the pressure of the side where there is no problem like the fujo of the oil varied suddenly a continuous flow was seen and as it lost the pressure, I do not know if everyone must work at the same rhythm of flow or if it is fired ... but in the case of the head where The same without climbing ... having if the next data serves you, the truck already has a very high mileage more than 200mil, but when the heads were removed, the mechanic commented that the shirts were in good condition since it did not have wear and still had a lot of useful life ... it can be that it requires the change of pump due to the mileage it presents?

In the case of the bearings you mention in the camshaft here it is necessary to remove it and take it to the rectifier for its adjustment or what is the recommendation. I appreciate your comments