This is what I did
I used purple power with a power washer made sure all the big stuff was off and clean. after it was clean I used DAWN dish soap to and washed the engine bay several time, stuff cuts anything away. I had an issue with a battery tray that rusted, so I sandblasted and cut and re welded metal. After fixing small issues I re washed with dawn again. I use metal steel wool, small scotch bright pads and several diff sand papers. This is what takes the most time is making sure you scuff up everything. After the engine bay was complete I Washed with DAWN again. My first step was to seal the engine bay. I use a DuPont sealer/ primer
http://i55.photobucket.com/albums/g127/boosted98gst1998/240sx19.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/240sx21.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/240sx22.jpg
After it was sealed and baked on, I went over all the primer with steel wool and wet sanded a lot of the bigger areas. After I made sure everything was glass smooth I washed it again with dawn and let to dry.
http://i55.photobucket.com/albums/g127/boosted98gst1998/240sx23.jpg
After going to the paint store and searching I found my color.
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint2.jpg
I prepped the engine bay, and made sure everything was aired off and the I tacked everything off.
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint3.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint4.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint5.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint7.jpg
http://i55.photobucket.com/albums/g127/boosted98gst1998/paint6.jpg