Cold Idle : 60 PSI
Cold @ 2000: 62 PSI

Hot Idle : 24 PSI
Hot @ 2000: 56 PSI

I've been running Rotella Triple Protection 15W40 up until the last oil change
when I switched to T6 5W40, just to see if it would make any difference.

 

Clean out the supply tower? And the hole that it has which passes thru to the block? All oil comes thru this one hole in each head.

 

I cleaned that part on the actual assemblies, but I didn't clean the part on the head itself. Looks like I've got something to do now.

 

a cheap gun cleaning hit comes in handy to clean oil ports

 

I think you could do it from the assembly side, don't pull head off, you will find that there is only one oil supply, the other three towers are just supports. It is a straight line thru the head to the block, where it changes direction. Would suggest an initial probe with a smaller than the hole diameter stiff wire. Mine had the gunk you can see, no sense squashing that into a bigger ball of gunk. Can also follow up with squirts of carb cleaner. Previous pix shows a piece of baling wire poked thru.

You will note from these pix that heads are symetrical, there are two water inlet channels and two oil holes. But on the block only one of each is used. So one hole may appear highly gunked, because it has zero flow all the time. On my block I found a small dot of gunk from the unused hole.

You could crank truck with assembly removed, rag over hole to catch oil pumped up, all valves would be closed (no interference).

When you removed the assembly, you did not change the order of the existing valve rods that rest on the lifters? Seems like you could listen to valve covers with a stick and narrow it down.

 

Got everything back together, took it for a test drive, and it sounds wonderful. Except for the tick. I think I'm gonna give Auto RX a shot before I drop the money on new rocker assemblies, maybe I'll be another to get their tick fixed by it.

At least I got to do a bit of cleaning and painting.

 

I used the Auto RX on a big John Deere turbo in-line six, 30 quart oil pan. Put in several bottles. Freed up rings, oil smoking went back to normal for a diesel. Equipment had set up for several years in Jacksonville at Navy base. There are other solvents like BG products to consider as well.

But if it is a liner tick, you will be walking another path.

 

I just finished my valley gasket, new rocker arms/shafts install this morning. My tick is gone.

There is a technical bulletin about rocker arms with a date code of 00 or earlier that can cause a tick because the push rod cup is loose in the arm.

 

Mine was built May 3rd, 2001. Even before I read your post, I wished I had changed my rocker arms when I did my intake manifold gaskets. At the time, I was taking a "Fix what is broke and only what is broke" attitude. Or course, I was helped along with this by The Minister of Finance (AKA SWMBO, AKA Secretary of War.) But if i had only known then what I know now...

My tick is most (and really only) prevalent from 1500 to 1750 rpm under load. According to previous owner, it has been this way now for 45,000 miles (his mileage and mine.) Tell me, does this match your now repaired previous symptoms?

 

Mine ticked at idle