Mark,

I did a few things.

First, I remoced everything that was in the way and most of what was to be painted gray. Then I used an engine cleaner making sure any accumulated grease was broken up. I did that with a few stiff bristle brushes. Then I pressure washed it.

With a clean and dry engine I used a paint prep product that removes wax and grease making sure to use several cleaning cloths.

I then used Scotchbrite pads to rough up the paint and then followed with another wipe down with the paint prep product.

Then it's just a matter of masking what doesn't get painted. I used tape and paper. It was later suggested aluminum foil is better as it is more conformal than paper. That makes sense.