Detailing and Dressing Up Your Miata’s Engine Bay

Posted on 10. Aug, 2009 by jeffz in Tech

Words and photos by Spencer Lynn of SOCALM

If a hundred members of your club lined up their Miatas on any given Saturday, you would probably find ninety-eight of them detailed and glossy. What would you discover if they popped their hoods?

I posted a thread about engine bays on the Miata.net forum and one particular post got my attention.

Gene Mallard, a moderator on the forum, wrote:

“You do it once when you buy the car, and from there on it’s easy to maintain. For example when I changed the radiator on my last Miata, I took an extra two hours or so cleaning, polishing and/or waxing all the parts that are inaccessible with the radiator in place. It applies when I do any work under the hood. Part of any job includes cleaning all the areas that are accessible once the part is removed, cruise control, clutch master, coolant overflow tank, whatever. Wax or paint protection is just as essential to protect and preserve the paint under the hood as it is anywhere else on the car, since it helps prevent the start of rust situations caused by sitting moisture. I always make sure that water beads up under my headlights, just as well as it does on my hood.”

Several owners asked how I began with my engine bay, so I wrote the following primer.

To begin detailing your motor:

First, use masking or painter’s tape to protect electrical connections from spray cleaners and water spray (masking or painter’s tape do not leave adhesive residue behind). Take your time and do a thorough job to avoid headaches later. Seal off the air intake snorkel or air filter with a plastic bag and a rubber band or a bungee cord. Be sure to seal around the spark plug cable openings in the valve cover because you do not want water collecting down in your spark plug’s wells. Then use a spray degreaser like “GUNK ENGINE BRITE” and, liberally, treat the whole engine and compartment.

One owner swears by a bathroom spray cleaner called “Scrubbing Bubbles” that you coat the whole engine and compartment with, then flood it off with ample amounts of water without a nozzle. Other owners report positive results with it, however, I prefer something that degreases. A small brush helps in stubborn nooks and crannies. Plan to use an entire can or two for ”grunged” out bays. After that, you need a sprayer attachment or nozzle on your hose to clean and flush the cleaner and residue from your motor.

When you’re done, start the motor to run for a few minutes while removing the protective measures and use an air compressor (if you have one) to expel water traces. Use some clean cloths and a general-purpose, spray cleaner like “Simple Green” to take care of leftover spots. That should put it in good condition. There are a number of excellent spray-on waxes available, and they are perfect for under the hood applications. Spray the wax onto those painted surfaces you can’t really get to with a cloth to wipe. You will feel better knowing those hard to reach areas will have a coating of protection.

Six years ago when the motor was being rebuilt, I found a machine shop owner willing to polish my valve cover while I had it off. That little machine shop has long since gone away, but there are others out there if you do a little looking. I liked the results of the polished valve cover so much that I planned on doing the intake manifold and exhaust heat shield. I located a used manifold and heat shield from a salvage company and found another machine shop that polished them to a beautiful shine. I swapped them out for my existing parts and put them up for sale for the next owner who wanted to do the same thing without suffering extra downtime for his car. The heat shield discolored once it heated up, but the results were not objectionable and it still looks good.

Moss sells a kit of silicone tubing in blue, red and black, but you can find similar kits at parts stores. They sell split loom covering in blue, black, red and simulated chrome. It comes in different diameters and is simple to cut and install. Split loom works well covering bundles of wiring and metal tubing or wire cables. NGK and Cobalt make blue spark plug cables and Jackson Racing and Magnecor make red ones. They add a nice touch if you use those colors for accent.

My pal and fellow SOCALM member, Dave Davis, has an intake manifold with a natural finish that is rough and almost appears “crinkle” textured. It looks great just as it is, next to his polished and highlight painted valve cover. Some owners carry a theme color throughout their engine bay, and mine is blue. I changed hoses and vacuum lines with the blue silicone tubing and split loom.

Dave’s Miata is black and he chose red as an accent. He was more conservative in his use of the red silicone tubing. His motor looks great, especially with the beefy, “Cobalt”, chrome, shock tower brace that center mounts on the firewall and gives the effect of framing his motor. He masked the raised, cross section at the front of the valve cover, and painted it red, leaving a Miata “M” script logo of polished metal exposed. It really has a classy look and I have never seen one just like it. He also fabricated and polished some diamond plate stock to fit that area just in front of the radiator. He slipped a section of red silicone tubing over his dipstick loop, for a nice touch.

I use a multi-metal, polishing paste on my intake, valve cover and heat shield to keep them freshly shined. Occasionally, I will treat all of the rubber, silicone and plastic with “Armor All Ultra Shine” spray, because I prefer the appearance it gives to those surfaces. That brand also makes a similar product that leaves a semi-gloss result.

I bought a pair of salvaged coolant overflow and windshield washer tanks and painted them “Krylon” silver. By itself, the painted plastic is vulnerable to marring of the finish. I treated them to three coats of “Krylon” clear and that gave them durability, but darkened the color to an aluminum shade. It was different and I had never seen the tanks painted before, but they looked good.

I recently posted a thread in the forum titled, “Show us your detailed engine bay.” It got a great response and quite a few Miata owners posted photos of their engines. They were in various stages of improvement from clean but stock to really tricked out with turbo-charger set-ups. Some valve covers were painted or powder coated in striking colors but polishing them was most prevalent and I saw one that was chrome plated. Some ambitious souls polished their own.

There were a couple of grungy looking examples from some curmudgeons, making the point that they could care less what it looks like under their hood. One who responded said looking at my motor revealed its’ appearance was “obviously the product of a sick mind.” Well, I am perfectly sound in mind but maybe a little picky at times and definitely not obsessive-compulsive, like someone else joked. Some non-owners who see my Miata think it looks like a new car. It is definitely a daily driver with 152,000 miles and shows the small dings and dimples from parking lots, but it is always clean and polished. That includes the engine bay, which gets a little attention when I wash the car.

I think that detailing your motor and engine bay is not really “going over the top”, it just shows pride of ownership for those of us who actually make this car their hobby. It may bear the original paint but its’ age and blemishes should not keep you from lovingly waxing, polishing and detailing it inside and out, what you readily see and what you don’t. It makes you feel good when you are finished and you climb in for a drive. I do not expect every owner to be as enthusiastic as I am about it, but I certainly take notice when I have found another Miata-phite, like Dave Davis with the same pride and passion for his roadster. We pop our hoods and enjoy exchanging ideas and admiring the other’s work. It is great fun owning and sharing with these cars.

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