Rod/Main bearing questions

KBMKVIII · Apr 1, 2020

Just pulled the bearings out for a rebuild and I have some crazy looking spalling/pitting on the factory rod and main bearings.
Always had quality oil with frequent oci’s of about 4-5k miles.
What could cause this damage?
Crank looks fine and will be getting a polish.
Billet rods going back in.

Magnum PD · Apr 1, 2020

How many miles? Stock bearings? Stock bottom end?

KBMKVIII · Apr 1, 2020

261k mi and stock bottom.
Same bearings it rolled out of the factory with.
I had 350/200s for maybe 10k of those mild with extremely mild tunes from gearman.

mandkole · Apr 7, 2020

Hmm.. It certainly doesn’t owe you anything but I think I’d be mic’ing the journals and rod ends closely.

Assembly and component design have improved over the years. I’ve seen recent 1m mile big truck engines with amazing looking parts with typical care and OCIs.

KBMKVIII · Apr 7, 2020

Well I am pretty sure I know what happened now.
Talking with my machinist he said it is definitely lack of lubrication.
The worst of the bearings were the mains of 3-4. This is exactly where I tapped the oil galley in the block for a second feed for my twin 17* pumps.
It will not be reinstalled the same way.
Going to draw from the oil filter housing instead.
Funny a few years back I was told by some others doing the same, it was the best place.
Well they are definitely wrong.
If you need a secondary feed for big oil make sure it’s on the oil filter housing where the plug is, not the oil galley.
Lesson learned.
Crank miced near perfect and is getting a very light polish.