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Learn To Paint Your Engine Compartment

Dumping the old engine for a bigger, badder one? Why not learn to paint your engine compartment

We got caught up in a mad dash to ditch the farm-tractor inline-six the Rambler was delivered with in favor of a proper V-8 and decided to fog the engine compartment flat black. And while flat black is almost universally cool, there was really nothing wrong with the factory Barbados Blue we painted over. So while the Rambler awaits what will be its third engine, we decided to restore the engine compartment to its original hue.

Unlike a body-on-frame design, unibody cars announce their presence boldly, with tall, broad shock towers often accompanied by firewall bracing. The effect is a more intimate relationship between the engine itself and the car's chassis, the balance of which is struck by matching the engine compartment to the car's exterior color. Simply speaking, our shiny blue-and-aluminum 360 won't show as well in a flat black hole, so back to Barbados Blue we go. Enough with the aesthetic musings, here's how we got it done.

Things to ConsiderAlthough painting an engine compartment is not as big an undertaking as respraying an entire car, the planning and prep work involved are the same. You need to consider the following factors: How good do you want it to look, and how long do you want it to last? Since we are in it for the long haul with the Rambler, we decided to do the best job possible. We chose to spray 2K (or two-part) products in a two-stage process.

Two-stage means the color coat and clearcoat are applied in two separate steps. In a single-stage process, the color coat also serves as the topcoat, as it's designed to dry to a more glossy finish. These paints can give excellent results that will last a long time, but we prefer the extra layer of protection that a two-stage clearcoat provides.

A 2K product refers to a material that requires a catalyst, usually called an activator, which enables the paint to cure after application. As opposed to 1K products, usually spray-can products, lacquers, and materials that only require thinning before spraying, 2K products are moisture resistant and will protect your sheetmetal better.

The safest thing to paint over is factory paint. You can be fairly confident that it was applied properly, and therefore, you may only have to scuff it lightly and paint right over it-no primer needed. However, if you are unsure of the quality of the work you'll be painting over, we recommend using a sealer. Sealer does exactly what the name implies: It serves as a barrier between what was and what will be. It provides a clean, stable area to prime and paint over that will be unaffected by anything that lies below. Because of our dodgy flat-black assault, we decided to err on the side of caution and use a sealer. We also chose urethane products because they tend to be more durable than acrylic enamels. Once those decisions were made, our plan fell into place. Here are the steps we took: clean and degrease, sand, seal, prime, and paint.

The crossmember then got a liberal coat of Eastwood Rust Encapsulator and was allowed 24 hours to dry. We decided to leave the crossmember black, so it got sprayed with VHT's satin black enamel from an aerosol can.

Next, we sanded the entire engine compartment with 320-grit wet/dry paper wrapped around a rubber sanding block. There's no need to sand down to bare metal, but it is important to sand everything that will be painted.

This gives the new paint a textured surface to stick to-note the darker, unsanded areas above the steering column in the accompanying photo.

During this process, some rust bubbles were unearthed in the area under where the battery tray had been. The rust didn't stand a chance against an 80-grit disc followed by several passes with a red Scotch-Brite disc. Then, the edges were feathered by hand with 320-grit paper.

Any areas of bare metal must be treated with an etching primer or a dedicated direct-to-metal primer before proceeding. For this project, we sprayed any bare metal spots with a couple of light coats of SEM's Self Etching Primer.

Next, we masked and covered the car. We also took the time to cover the adjacent cars-you'd be surprised how far overspray can travel. Then, the entire engine compartment was blasted off with compressed air followed by a dousing of Eastwood PRE cleaner and paint-prep solution. Even though this is just an engine compartment, dirt and dust will still look ugly embedded in its new paint.

Proper mixing of all materials is crucial or funny things will happen to your paint job over time. Follow the directions on the can closely, or better yet, follow the procedures on the product's technical data sheet if you have access to it. DuPont's 2840S sealer is a two-part urethane that must be mixed with an activator at a 2:1 ratio. Be sure to stir the mixture thoroughly and strain as you pour it into the paint cup.

Check the air pressure before spraying. Most HVLP (high volume, low pressure) guns are designed to work with about 8-10 psi at the gun cap. Accounting for the pressure drop through the gun, this equals about 26-28 psi at the heel (i.e., inlet) of the gun. We used a "cheater valve" regulator on the air fitting; however, if you plan on doing a lot of spraying, a wall-mounted regulator to connect your air hose into is preferable. They provide more consistent air pressure and, since they often incorporate a filter and water separator, that air is clean and dry.

The sealer was applied in one full-wet coat. Since it dries quickly, it can be topcoated in less than an hour. If it's allowed to dry for more than four hours, however, it will need to be scuff-sanded before being painted over.

The primer is also a two-part product. DuPont's V-4904S Primer-Filler gets mixed in a 3:1 ratio with a temperature-dependent activator-the mid-temperature activator in this case, since it was about 70 degrees F.

The primer can be applied in relatively thick coats to fill and smooth sand scratches and other small surface imperfections. The Rambler received three medium-wet coats with about 6-8 minutes flash time between each coat. The primer also dries quickly and is ready to sand within one hour. DuPont recommends scuffing this primer with 500- or 600-grit paper before topcoating.

To prep for the color coat, the entire engine compartment was blown out again with compressed air and wiped thoroughly with an adhesive remover and then a tack cloth.

We purchased the AMC Barbados Blue custom-mixed from the paint store using AMC factory paint chips we scored on eBay. If you've got factory paint but don't know its name or number, check eBay. We found a ton of paint-chip listings-even for oddball applications like Citroen, Vauxhall, and Rover. After mixing the paint with an activator, it was ready to spray. We switched to a smaller spray gun to ensure we'd be able to get behind and around the steering column, brake lines, and wiring harness. To apply the basecoat, spray enough material in medium-wet coats until coverage is complete-usually 2-3 coats will do the trick. Allow about 8-10 minutes of flash time between coats.

We shot the clear as soon as the basecoat was dry-after about 30 minutes. We chose DuPont's HC2300S clear, which was mixed in a 4:1 ratio with a medium-temperature activator. Only two medium-wet coats were needed, applied five minutes apart, before the engine compartment was finished. The 2300S dries very quickly and can be polished after only two hours. While we won't be buffing out the Rambler's engine compartment, the clearcoat was dry to the touch and ready to be unmasked by the time we were finished cleaning the paint gun.

The Learning Curve
This is a good project for beginners. The prep and procedure are all the same as a for full-blown paint job, but the stakes are much lower, and therefore there is more room for trial-and-error learning. Here are two things we learned while doing this project.

Paint And Prices
DescriptionPrice
DuPont 2840S primer-sealer, 1 gal.$113.00
DuPont 2805S activator, 1 qt.$34.02
DuPont V-4904S 2K UltraProductive primer-filler, 1 gal.$123.00
DuPont V-4975S activator, 1 qt.$61.00
Nason basecoat, 1/2 gal.$40.00
Nason activator, 1 qt.$28.40
DuPont HC2300S clear, 1 gal.$151.79
DuPont HC2305S activator, 1 qt.$47.69
3M 320-grit wet or dry sandpaper, 100 ct.$35.29
Sharpe air regulator$27.00
Inline air filter$47.00
Total$708.19

All materials purchased at Annex Automotive and Industrial Finishes in Los Angeles; 323/934-3177.

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SOURCES
The Eastwood CompanyPowerbuilt Tools/Alltrade
Pottstown, PALong Beach, CA
800/343-9353800/368-6653
eastwoodco.comalltradetools.com
25 comments
Andriw Bern
Andriw Bern

Me darian un curso de pintura.... xfavor

Larry Hullinger
Larry Hullinger

I used newspaper for years when I used to paint cars never had a problem !!!

Randy Todriff
Randy Todriff

Note to First time Mopar owners Never ever paint your engine bay Black its body color for Mopars

Ian Big-e Hoffman
Ian Big-e Hoffman

I've never had any problems using newspaper either so if its bleeding through you should stop spraying the newspaper and spray the car or project

Matt Williams
Matt Williams

I got my copy today and was surprised to see the word Volvo appears twice in two issues.

Ryan Chevalier
Ryan Chevalier

Put up some pics of the thirdgen in the background!

Keith Kavon
Keith Kavon

it looks like to me, like the job was half assed. I could point out everything i see that didn't seem like the best route to take, but i don't want to write a long paragraph, and as a mechanic i dont like to bash other people's methods. Judge by the finish poroduct. But, all i can really say is if this, is suppose to be one of your best jobs, like the article said you were shooting for, I would never want to bring any my projects there.

Craig Palmer
Craig Palmer

why is the lettering so small, gotta put my face right upto the screen to read it all.

Ralph Laakmann
Ralph Laakmann

and the paint on the newspaper....why are you putting costly paint on the newspaper....it belongs on the job.....

Ralph Laakmann
Ralph Laakmann

if you are bleeding thru newspaper.....you are sagging and running....Iv'e used newspapers to mask off even House of color candies and never bled thru....

Keith Inskeep
Keith Inskeep

been there done that more times than i can count but it is so worth it

Karl Loper
Karl Loper

Now take a tack rag or an alcohol rag and wipe off the oils that your left hand just transmitted to the surface.

Jae Cho
Jae Cho

Yup this is a big Fail. Newspaper is a dust source too plus the bleeding.

Brandon Quinn
Brandon Quinn

First tip don't use newspaper, go to a paint supplier shop and pay 10-15 bucks for good paper.

J-f Dube
J-f Dube

All I say is SCRUB LOTS before you paint.

Jason Sahloff
Jason Sahloff

Don't use newspaper, paint can bleed through it

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