I've done the oil pan gasket few months ago and it had sludge in bottom. The pickup tube was basically clear only few pieces or dirt stuck in screen. The crank and rods were clean as far as i remember.

The lower intake, upper intake and valve cover gasket been changed by me about a year ago. I have no oil leaks now.

As for the lower intake underside is had a layer of crud, enough to coat the metal.

 

Have you ever seen buildup on a bearing? I have not. Like I said before the sludge does not really form under pressure or it is simply washed away. I cannot ever remember digging sludge out of seals and bearing are always shinny. Sludge is more likely to cause a seal to fail due to friction then to help it withany type of support. The biggest place I would worry about inside the pressurized part of the engine would be the passage ways. The pressure keeps them pretty clean also. Staining is the worst I have seen.

When I was in high school I remember shade tree mechanic telling a friend of mine not to change the oil because that was all that was holding the motor together. 5 years later I ask my engine rebuild teacher if that was true. He said it is the exact opposite. Cleaner the better, dirt and sludge does damage in any form. In the 7 years wrenched full time I have never seen or heard of anything that says my teacher was wrong.
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The question would come to mind would be where is the crap filling your filter coming from?

Once you clean out the oil pan you would almost need that to "refill" with crud before you would start getting the filter to fill up quickly.

Normally after you have cleaned under the intake, oil pan and valve covers then do a couple of oil changes your done. You can not even tell this was a sludged up car.

 

link is to build up on bearing, picture is build up around the bearing. if its this bad replace engine.
http://underthehood.mahleclevite.com...ingsludge2.jpg

 

Most likely both of the heads stuff is still breaking lose and making filter dirty. The picture of the filter I post didnt have any dirt really it was just dirty.

 

I have put crank kits in Dozens of engines but also as mechanic you get to see what most of the guys in the shop are doing. I have never seen a motor sludged up that bad. I seriously doubt that motor was getting any oil to the valves. I still stand by my earlier post. Cleaning that craps out of the motor is still better then leaving it in. Higher oil pressure is nice, higher oil pressure by choking off the flow of oil to other parts of the motor is the fastest way to scrap a motor.

Edit: Now that I think about it I may have seen cars like this, we just did not waste the time with the tear down.

Car would come in with a "starter issue"
Engine is hard to turn by hand.
Remove plugs, Engine is still hard to turn by hand
Remove oil drain plug,, insert screw driver in the oil drain hole so the tar like substance can start to ozzz out.
Call customer tell them they need a new engine.
In most cases car leaves on a tow truck. (none of the dealerships I worked for would install a used motor.)