I just went through an engine. The main and rod bearings washed out and the crank journals were scored. Unfortunately I didn't cut open the
oil filter after the first
oil change; if I had I probably would have seen the same thing your seeing.
I started to see a decrease in my
oil pressure and then I started burning oil like crazy.
Have you noticed a decrease in oil pressure? If the bearing washed out the oil pressure would surely decrease.
Before you pull the engine, drop the pan and remove one or two of the main and rod bearing caps and inspect the bearings and journals. If they didn't wash out they should still have a dull even babbit coating. If they are shiny then they for sure washed out and need to be replaced.
If the journals didn't get scored you might be able to reuse the crank without having it reground. My crank was scored and I had to have it reground .020 under.
From what you say, it sounds like you may have contaminated the oil with filings and you probably will want to pull the block anyway to thoroughly clean out all the oil passages. If you had a decrease in oil pressure and if the engine ran very hot there is a chance that you wore down the cylinder walls. So, you'll probably want to have the bores measured to be sure that you didn't wear them out of clearance.
My bores, on a supposed .030 over rebore, were on average .036" at the centers of the bores. I could have had the block rebored to .040 or .060 over but I would have had to get new pistons and mine were already balanced. I got another block that hadn't been overbored and had it bored .030 over, and I rebuilt the block myself.
I am currently going back & forth with the builder who built my first block and hopefully we can reach an amicable agreement as far as compensation for the bad block/workmanship he provided.
Good luck and I hope your problem is not as bad as mine was.
Tony