Technical Looking for some help with a nasty noise

And here are what I thought were the run/score marks

 

don't know about the piston, did ya find the piece in the oil pan? the marks look like casting clean up marks.

 

Ok cool, good to know not everything is rubbing.

No I couldn't find any piece or pieces in the oil pan or oil that was drained. But the sludge in the bottom of the pan did have a silver sheen to it

 

Piston damage looks old. New damage would have bright metal, not dark. I agree with Pat, those are probably grinder marks from the factory cleaning up casting core flashing. No problem there.

I still think you have a wire terminal or some other foreign material on top of a piston. You had good oil pressure, so the crank and rods are probably fine.

 

Fabber, I have the head off as well and was hoping that it was something as simple as that.

Thank you for the Info on the piston as well. I can rule that out and keep moving along the list.

 

the real loose cap the crank is discolored like its building up heat on the thrust face , Pull the cap and look at the bearing if there is any left . , IMo there is too much side play in the other one it should only be 2-3 thousandths not hundredths .

 

Found the source of my noise today....the crack that you see is actually the highest point

 

Wellll,,,, pull all the pistons, if the ridge isn't too bad,, your 1/2 way there now.
As said mark the rods & caps & position. 1-2 etc..

 

I don't know if the block is salvageable, I think this was from me getting a little too aggressive with a flat head screwdriver and hammer in an attempt to break loose the old water distribution tube.

 

A crack might cause it to leak, either compression into the water jacket, or water into the cylinder, but I can't see how it would cause a knock. What did your bearings look like? I hadn't noticed the blue crank throw before Stimpy mentioned it. That's a bad omen. He's right that it should only have a few thousandths side clearance, but it has probably been living quietly like that a very long time or you would have a lot of metal in your oil. I'm concerned about that blued crank journal. What did that bearing look like.

 

The crack is noticeably raised inside the cylinder. Imagine pushing your thumb into the side of a soda can and what it would look like on the inside. It's not very easy to see in the video but when you run your finger up and down the cylinder it's extremely noticeable that it's raised. The piston is catching it on the way up and down. The engine is easy to turn over by hand until you get to that point then it snags and is easy after it p***es. I'll try to put a straight edge on it to show the amount that it's raised up.

 

I can clearly see that crack and the raised portion of the piston wall in the video. At least until the piston comes up.

 

I watched it a couple more times. Maybe I can see it. Sort of horizontal. You're probably right about your screwdriver. If it doesn't go to the top or bottom you can hopefully fix it with a sleeve and not have to hunt up another block.