That's surprising........

 

My guess is that it was a recent development, but it's odd that after inspecting everything else, this center cam bearing is the ONLY thing in the entire engine that shows any signs of corrosion or erosion. All other cam and crank/piston journals and bearings (and oil pump) show such minimal wear that they are still within OEM factory specs. I guess that says something for a scheduled maintenance such as police departments do.
That said, AFAIK (since I'm not the first owner) there has never been a coolant leak into the oil, and oil changes have always included filter changes (as they should). The only buildup of any kind has only been carbonization in the combustion chamber - as shown in my prior pics.
I've looked around on a few sites regarding bearing damage, and my issue doesn't seem to fit any of them so far. I'm wondering that since the damage is only on the one bearing that maybe there was an inherent flaw/weakness in that one bearing that was exposed during the chemical cleaning of the block when it was recently at the machine shop.
However, what is unusual about this particular damage is that:

1. It is the only bearing that shows damage or abnormal wear of any type,
2. The damage is not linear - there is an irregular pattern that does not correspond to the relative movement of the camshaft,
3. The "high" portions of the damaged area doesn't show scoring,
4. There is no "fade" between the low and the high spots,
5. The damage is limited to only the 1st 1/4 of the inner bearing surface starting at the oil supply hole,
6. There is no visible damage or measurable wear on the respective cam journal,
7. There was no binding or grinding when rotating the camshaft by hand either before removal or after bearing replacement and cam reinstallation.

 

Wonder if something got caught in there......

 

I thought that at first but discounted it later because if something was caught then there would be score marks on both the bearing and the journal in line with the relative motion between the two, but there are none.

 

The journal is a LOT harder metal than the bearing though.......

Probably one of those things that we will never get an answer to.

 

Rotating parts in (crank, pistons, cam, oil pump, timing gear)...

 

Oooooo, pretty.

 

Engine assembled - ready to insert...

 

Almost looks like the one I have to go in my truck....

 

Gotta admit - the blocks look good in Hemi Orange!