Rod/Main bearing questions

KBMKVIII

Well-known member
Joined
Apr 9, 2012
Messages
1,475
Reaction score
26
Location
Texas
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.

1ac1243f8f2c0a1c086af702f0da54c8.jpg


fb40f1c5d7d0049e8473bf238fc05d09.jpg


457f0c652aa8f87acbf143beff105271.jpg


03069a3a0cec2c3a4b869eb33ac9c7e9.jpg
 

KBMKVIII

Well-known member
Joined
Apr 9, 2012
Messages
1,475
Reaction score
26
Location
Texas
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

Active member
Joined
Jan 14, 2012
Messages
2,303
Reaction score
2
Location
Northwest
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

Well-known member
Joined
Apr 9, 2012
Messages
1,475
Reaction score
26
Location
Texas
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.
 

Latest posts

Members online

Top