Removing flash rust & old paint

The next step in cleaning the block is to get rid of the flash rust and the paint residue. Why? First of all, even the small amount of flash rust inside the block will come off at some point, be carried along with the oil flow and find it's way between moving parts to do damage. Or in the oil filter, to reduce it's filtering capacity. The paint is important to remove so a new, fresh one can be applied to protect from outside elements (water, road salt, acids etc).

Removing flash rust, paint and even thicker layers of rust that may have formed over time is easy, provided the block is completely free of oil and moisture. You just take two of the most common wire wheels, attach them to your hand held drill and start a one-hour attack against the block!

A lot of dust and paint particles will be flying around, it's a messy operation, so I did this outside as well. The block is cast iron and will not be harmed by the wire wheels, no matter how hard you work. That goes for the block deck (cylinder head surface) as well. The wire strings are just not hard enough to deform the iron or scratch it. To be on the safe side, I was careful around the cylinders, just in case. They need to be honed with a specific tool, so don't go there.

After I felt I was done, I blasted the dusty, bone dry block with compressed air. Here's the result:

Starting to look like something that could be a working engine some day? Yes :) Before declaring it good, I will look into quite a few issues yet, so let's be happy that these work phases were carried out succesfully but not be too jubilant yet.

By the way, the block is now more or less exposed cast iron. For all practical purposes, it's vulnerable to water and moisture in the air, prone to rust again quite easily! To prevent this, I took a rag and quickly dipped it in engine oil, then wiped down the block with it. Just a thin film of oil will be enough to protect it, especially as it "lives" in a warm garage.