Engine Painting
Engine painting is not all that difficult. Here are some simple instructions that we have found to be the best match. By John Ligon…
With regard to engine painting, I have had excellent results using the special family of high temperature acrylic engine enamels available at automotive finish distributors (*not* your local retail “hobby” stores featuring air fresheners and chrome gearshift knobs).
These are enamels intended for use where the anticipated temperatures are above the limits of exterior finishes, but below those for really hot applications like exhaust manifolds.
Although they, like most automotive finishes today, are considered hazmats, rubber kitchen gloves, plastic goggles, and long sleeves are about all the protection you need if applying by brush outdoors.
And yes, with a good bristle brush, you can get a very presentable finish straight from the can with little or no reducer and with the bonus of no waste to over-spray. And unlike spray applications, you can remove runs completely by brushing over In The Direction, or Perpendicular To, The Run. This means you work from top to bottom, catching boo-boos on the fly and then rotate the work piece so the majority of surfaces are horizontal during cure (helps minimize “stealth” drips behind your back when you go on to something else).
There is some blending involved: you do add a small amount of hardener, and the “pot life” of the resulting brew is about four hours.
Use solvent grade (cheapo) lacquer thinner for cleanup (but *never* for reducing!!!).
One-half pint is enough for about two engines.
Proper preparation is critical to getting the paint to stick and stay. I follow a multi-step approach:
- Engine degreaser and elbow grease
- (in general sequence: scraper, wire brush, laundry brush, toothbrush, scouring pad, sponge)
- Liquid kitchen soap (washes away residual grease and degreaser residue)
- Sodium phosphate (chemically cleans and conditions the metal surface)
Metalprep (chemically alters the surface of steel and cast iron to inhibit rust and provides an important bonding agent) - High temperature acrylic primer (smoothes out the rough spots and provides an additional bonding-to-finish-coat transition)
High temperature acrylic engine enamel:
Allow two weeks” curing time before rubbing out imperfections and final assembly; touch up installed engine with artist’s brush.
Although not quite deserving of top honors at Hershey or Pebble Beach, your engine will look far better than anything that ever came from the factory.
PDF 
on my engine, i scrubed with brake cleaner, “purple” degreaser, a wire brush, assorted scrapers and emory cloth. once i had it as clean as i thought it was going to get, i masked the engine compartment with butcher paper and tin foil and sprayed it with primer for farm implements from the local farm store. i then sprayed it with the corresponding IH red spray paint. two coats of each. it came out pretty good (i think) but has not been in service that long, so we’ll see about longevity.
http://i254.photobucket.com/albums/hh115/suprjohn/plugwires.jpg
Touch ups can be sprayed on without much overspray if you use a toilet paper roll, or tube from paper towel. Spray thru this, localizing the spray.