I finally got my engine running again x 4. Fought with low oil pressure till I finally put on a new front cover. Now at operating temp I have 25 psi. Still had a tap so I swapped in some new rockers, shafts and push rods.

The tap went away till the temp got up to 205-208. So, just for ****s, I started pulling plug wires to see if I could isolate the cylinder. Lo and Behold! The #2 cylinder is where the noise is coming from.

Now that begs the question, if its a slipped liner, why does the tap go away when I remove the firing stroke by removing the plug wire? My experience has been that this diagnosis is sure fire way to detect a loose rod bearing.

Being that the block is already up to temp, why wouldn’t the tap of a loose liner continue, regardless of the cylinder firing or not?

 

If the tap goes away when the plug wire is removed, it could technically still be either, or a piston with a worn skirt.
The bearing or piston noise *might* go away because, even though they are still moving, they have less force applied without a spark/explosion.
The liner moving *could* also be efffected by no spark, as there would again be less force on that piston, as well as less heat from no spark/explosion. The lesser amount of heat could be just enough that the liner does not move, until heated up a few more degrees.
1 degree may not sound like much, but 212 degrees F is boiling, where as 211, is just really hot.
I would pull the oil pan and check the rod bearing.
Hopefully that's it. Next, I would think the piston skirt diameter was worn below spec, and it is chattering up and down in the cylinder.
Slipped sleeve, maybe. And if it's one of any, I would replace All the bearings, pistons, and pin all 8 liners.
Which is exactly where I am now.
After lifters, pushrods, rockershafts, new oil pump(old one had cracked gear)didn't stop the ticking in my 04, 4.6, I took it completely apart.
I found all the main, rod, and cam bearings worn out, but good cylinders and crank (only needing hone and polish).
I also found 4 pistons(B size) below spec.
I can't say for sure which was the noise, but assume it was a combination.
Strangely, the engine just had a loud hammering tick after it warmed up. No typical knocking sound I would expect from a rod bearing. Maybe just how the sound resonates through the aluminum, dunno.