Got carried away with the RustOleum

About 35 years ago painting the inside of the block was the big rage. Over time, people had a lot of trouble with paint flaking off. Some claimed it helped oil return faster to the sump. As far as protecting the internal surfaces, my opinion is driving it regularly is the best.

Painted a block (external surface only) using the recommended primer with that system of engine paint. About 3 months later the topcoat of paint started flaking off. I could remove most of the paint with an air blower. The primer stayed with no flaking at all. I was told it was because I didn't run the engine and get the paint warm right after application.