This picture is of the #8 cylinder in a motor out of a 2001 E350, I am planning on putting it in a 2002 F250. It was purchased from a wrecking yard, supposedly it ran good when pulled with 163k miles on it. It was on an old tire on a pallet when I got it. The oil pan was punched with a forklift while it was on the pallet, so I am replacing the oil pan (the pan did not appear to have ever been off this motor before) , the motor is currently upside down on an engine stand. I had the oil tested by Blackstone labs before I started working on it, the test results came back good, no contaminents, normal wear metals, etc. It turns over easily by hand with a 24mm standard length wrench on the front crank bolt. Generally the inside of the motor under the oil pan looks good, the outside was very rusty. I can see honing/hash marks on all the cylinder walls. I was turning it over to replace the brazed piston oil jets with welded ones and I noticed this rust on one cylinder wall, #8. I wiped the right side in the picture with a gloved had, no rag or anything, it feels smooth, and it wipped clean easily, it looks like there is a little rust on the rings on this cylinder only.
I did pressure wash the motor a week ago when it was right side up on the stand, and some water got in the hole in the oil pan, I turned the motor upside down shortly after washing it, it has been sitting upside down for a week now, is there a chance this rust formed in a week, or could it be from condensation while the motor was sitting? Is this anythig to really worry about, or is it a sign of bad things happening to this motor. Anything else I should look for while it is upside down, and the pan is off of it?