After patching our inner fender, the bodywork began. This was performed just like bodywork on the outside panels. We began by sanding the entire engine bay with 180-grit sandpaper so we could see what we were dealing with. Fortunately, our engine bay had only one coat of black spray bomb over the original Winchester Gray. We don't recommend sanding through the original paint unless it's necessary to remove corrosion. Once sanded, rusty areas were treated with OSPHO (any rust preventative with phosphoric acid as the main ingredient will work) and then primed to prevent further oxidation. Now it gets monotonous, using filler we filled the low spots, paint chips, and such prior to block sanding with 180- or 220-grit paper. This step is repeated until all of the low spots and chips are gone, which in our case took going over the entire engine bay three times. Time consuming? Yes, but the end result was worth it. Remember the quality of the paint will only be as good as the prep work underneath, so take your time and get it right. A trick we use to find low spots while doing bodywork is to mist the entire area with dark spray paint, then block-sand it lightly. Low spots will show up the color of the spray paint. After the bodywork is complete to our satisfaction, we are ready to tape off and prime the engine bay.
Since our car will eventually be painted, we didn't worry about overspray on the tops of the fenders or top side of the hood and concentrated on taping off the windshield, front bumper, and other areas where we didn't want paint. The K-member and suspension can either be painted first and taped off, which is how we chose to do it, or the inner fenders, framerails, and firewall can be painted and taped off before painting the K-member and suspension. Either way, remember the body color goes all the way down to the bottom of the framerails to be correct. We painted our K-member and suspension with black, semi-gloss engine paint. Engine paint is more resistant to oil and grease and is durable. The semi-gloss black color is also similar to the original color of these components. Once the K-member was painted and the taping was complete, we sprayed the entire area with a lacquer-based primer. Lacquer primer is compatible with both original and modern paint systems, fills well, and is sandable-making it a good all-around choice for primer. After priming, you guessed it, more sanding-this time with 400-grit. Anything less than 400 will allow the sanding scratches to be visible through the paint, so our final sanding is always with 400 or finer paper. Spend extra time with a 400-grit Scotch-Brite pad scuffing the tight areas where the inner fenders meet the firewall, the bolt heads, and other places hard to reach with sandpaper. This scuffing will help the paint to adhere to the primer, keeping it from peeling later.
For paint, we called our local auto body supply store and purchased a quart of single stage urethane enamel with reducer and hardener. we took the advice of the paint store and used fast-acting hardener since we'd be spraying in fairly cool weather. If you don't understand the dynamics of paint, the place you buy your paint is a good place to ask questions or to ask for recommendations. Don't forget the mixing cups, sticks, and strainers while you're at the paint shop and always ask for the Material Safety Data Sheet (MSDS) for the type of paint you're using. The MSDS gives you information on mixing, spraying distance, air pressure, and clean-up for the paint you're using and is invaluable to complete the job correctly. Another item we picked up was an in-line water separator for our air hose. This is an inexpensive alternative to high-dollar units and is placed between the air hose and paint gun where it separates any fisheye causing water from the air coming from the compressor. The engine bay can be painted with a base/clear paint system, but for simplicity we chose single stage paint. we are not painters by any means, but by following directions on the Material Safety Data Sheet and having a clean, well-prepped surface, our engine bay paint turned out better than when the car was new. We didn't have a paint booth or fancy HVLP paint gun, but have found that we don't really need those items to perform a quality job. Painting, especially the engine bay, can be accomplished outdoors on a calm day with good results, or by creating a makeshift paint booth by hanging plastic in the garage bay to keep overspray off the rest of the stuff in your garage. Once the paint is given a day or so to cure, we'll be ready to start restoring the accessories and putting everything back together.
So there you have it, we stripped, prepped, and painted our engine bay in about two busy weekends worth of work and at a material cost of less than $100. Be sure to follow this project in our next issue as we clean, repair, paint, and replace the engine bay accessories, paint and detail our engine, and install it all so we can get our Road Runner back on the road.