I am running Rotella 10w-30. My car burns a quart every 1000 miles. I have about 1500 miles on this oil change.
150k on the engine. 180 compression in all cyls except #4 cyl (the one under the knock sensor) which has 170. Knock seems to originate from the middle of the block on that cyl, confirmed both my mechanics stethoscope and by ear. This just doesn't seem like piston slap to me.
The heads are new-ish or rebuilt, I believe the PO had an idler go bad on the timing belt and had to replace them. I don't think the problem is the lifters.
It did this (see vid above) on the maiden voyage right after I did the timing belt...
This is the closest thing I could find on youtube that was like it.