Repainting an Engine Bay in 8 Easy Steps

Photography by Carl Heideman

Sometimes you can’t just clean up the engine bay, and a repaint is the only answer. Although this sounds like a recipe for a long job involving an engine hoist and a couple of your best friends, if you work smartly and methodically you can do an engine bay repaint without pulling the drivetrain. 

We installed a Moss supercharger in our Triumph TR6, but before we installed it we needed to give its new home a fresh look. Here’s how we kept the job simple.

Step 1: Remove What You Can

We usually remove everything from the engine bay except the engine and wiring harness. We pull the heater, radiator, carbs, manifolds, and just about everything else, including all of the hoses. 

While we’ll leave the wiring harness in the car, we will usually disconnect just about everything—after careful labeling, of course. We can then clean up the harness, coil it up and tape it into a bag. With everything removed, we can move on to step two.

Step 2: Clean

Next comes many long hours with a brush, paper towels and our favorite cleaners. Note that we wear gloves to protect our hands from the evils of chemicals. This step is even more critical as part of a repainting job. In addition to the methods mentioned in the main story, we finish preparing the engine bay by scuffing everything up with a Scotch-Brite pad so the paint and primer will stick. 

Step 3: Prime

While our pictures show us priming the engine bay with a spray gun, you can do nearly as well with a spray can. The key is to get an even, consistent finish. 

You’ll note that we didn’t prime the engine. We later hit the engine with black primer. If we had sprayed it with gray primer, any chips would have shown up gray instead of black. Once the primer in the engine bay had dried, we followed up with the color coat. 

Step 4: Paint

Visit your local auto paint specialist. They should be able to match your engine bay’s original color and supply a pint or quart of the needed hue. While we did our TR6 engine bay with a spray gun, your local shop should be able to pack the correct color into spray cans too. We’ve done this in the past with excellent results.

We painted the engine with a rattle-can; first primer, then color. While a lot of people think you need high-temp engine paint, we’ve never been pleased with the price, quality or durability of the stuff. We just use a quality can of black enamel and have never had a problem. Touch up any missed spots on the engine and body with a brush.

Step 5: Clean and Paint the Accessories

The condition of the various under-hood accessories makes a huge difference. Case in point was our exhaust manifold. We first cleaned ours with a wire wheel before painting it with high-temp manifold paint. (This is different from high-temp engine paint). 

Step 6: Right the Wrongs

Most of our cars have seen three or more decades, and there’s usually some creative stuff going on in the engine bay—perhaps inappropriate rewiring or goofy hose-routing from emissions equipment removal. We fix all of these errors before we begin reassembly.

Step 7: Reassembly

We’re always very slow and deliberate as we put everything back together. We route the hoses carefully so they don’t twist around each other. We do the same thing with the wiring. 

We used replated fasteners to reassemble our TR6 engine bay. Companies like Eastwood make replating kits, or you can follow our lead and have a local industrial plater do it for you. 

Of course, sometimes it’s easier to just install new fasteners, especially if you’re not concerned with concours-correct bolt head markings.

If we really want to impress people, we’ll “time” all the screws and bolts so they’re in the same orientation. This is the fun part, so we always take the time to enjoy it and make it look great.

Step 8: Enjoy

Start to finish, we have about 30 hours in our engine bay detail and supercharger install. While the engine bay looks fast just standing still, the supercharger begs for a ride.

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300zxfreak Reader
9/24/20 11:33 a.m.

Remember, aluminum foil is one of your best friends for masking off oddball shapes.

MadScientistMatt PowerDork
9/24/20 12:30 p.m.
300zxfreak said:

Remember, aluminum foil is one of your best friends for masking off oddball shapes.

That sounds like it could be a tip I might need soon.

Munchen Fan
Munchen Fan New Reader
9/25/20 2:44 p.m.

Good article, thank you. 

Followed this procedure on a similar car, and MGC, some years ago. Pulled the engine and trans as it really needed a rear main seal replaced. Another of those little details one takes care of in such a project.

dougie Reader
9/25/20 11:42 p.m.


I've done that exercise a few times......


Jerry From LA
Jerry From LA SuperDork
1/20/21 4:54 p.m.

That new, freshly-torqued intake manifold gasket means better, smoother performance from idle to redline too.

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