So heres where I am at. Just about all of my enging block has been hit with a wire-wheel and scrubbed very well with degreaser and 409. I am tempted to trust the paint that is left on the block, because it is obviously resilient enough to survive the wire wheel. Should I keep going until all the paint is off, or is it ok to paint over this older paint? How bad will that look? What are your prior experiences with this?. And one more thing, what do you do with the freeze plugs? Its like painting teflon.
Leave them Natural color. Little bit of Masking tape,get the rusting surface clean again and use a degreaser for paint not a Soap.I like light Grey on My Engines, any kind of Leak can be Seen Immediately.
+1 mask off the freeze plugs.If you paint over the old, you will be able to tell. Wire wheels are not very effective on hard, thin paint. Have you tried to dissolve the old paint with thinner while scrubbing with a scuff pad? I bet stripper would take it right off, too. If you can't get it all off, you might want to consider using some primer first, and sanding it out a little before paint. To bury the edges somewhat.