When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Wondering what's caused this cylinder wall discoloration. I'm thinking it may be previous rust that has been smoothed over by running the engine. Compression was good on all cylinders. Crankshaft bearings didn't look that great either
That looks like a very poorly maintained motor. Looks like it got a couple oil changes in 300k miles, and ya that looks like putting from rust on the cylinder walls.
When a motor sits, there is always one cylinder with an exhaust valve open. My bone yard ly6 had a cylinder like that( well maybe not as bad?) I just used a red scotchbrite with some mystery oil and cleaned it up. Motor has been running strong for 20k boosted. Is it pitted? Can u feel it? Or just discoloration?
cylinder wall discoloration 
