How To Paint An Engine Smartly: Clean And Prep For A Smooth Finish

Nice pics of sleekly painted engines are nice to look at. But how do you go about preparing your bike before finishing the paint job?

Learning how to paint an engine might seem a challenging project. But for someone who’s handy with tools, it should be easy enough to apply a decent finish to with practice.

This guide is for owners who don’t mind getting a bit dirty with grease, washing, and spray paints. After you’ve read these quick guidelines for prepping and painting motorcycle engines, you’ll be ready to make yours shine.

Read also: 

How Much Does It Cost To Paint A Motorcycle?
Top 5 Best Engine Paints: Which One Is For Your Motorcycle?

DIY Painting Done Well

If you decide to do things by yourself, you’ll not only be proud if you did it right. You’ll have also saved a tidy sum that you could use for repairs and other improvements.

We recommend looking at simple options with spray-on colors and coating types in spray cans. But you don’t have to buy some huge compressor and spray-can setup and deal with the cleaning and over-spraying issues of low-pressure volume spraying.

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You’ll still be spending most of your time handling your bike’s parts and preparing them for coatings. The actual spraying itself might take only a few hours in between drying windows.

You’ll likely to put in more hours in actual painting than in prep. But much of that will be spent waiting for coats to dry or tack to form, which you can devote to practicing your technique.

If you are into doing things yourself, you may need an impact driver for your upcoming DIY projects.

How To Paint An Engine In Five Steps

CLEANING


Even if the engine is greasy all over, it’s still doable. Degreasers from your stove plus a few old toothbrushes are good for removing oily slime and grimy patches of dirt.

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Those tiny-tubed metal spiral brushes you see in use at shops are also very useful for scraping off debris. The brass ones, in particular, tend to be softer and less abrasive on aluminum casings.

Sandblasting surfaces will also work but the labor and prep time is not really necessary for small jobs like these.

Read this article to know clearly about how to clean an engine.

DISASSEMBLY


The parts that are usually removed before paintjobs are starter motors, valve covers, and intake manifolds. With brushes and cleaners, you will normally end up scraping most parts at least three times before leaving them to dry over two full days or so. The surfaces can then be blasted with a high-pressure air hose to remove other gunk prior to painting.

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After you’ve removed all debris and loose bits, you’ll need to scrape all surfaces to be painted. As fresh coats won’t adhere to polished surfaces, you’ll be sanding these down for a better hold. Sanding also take offs any existing films due to excess cleaner or wax build-up.

To keep the bolt holes for the exhaust and carb headers free of chemical action, you can stuff wads of paper or cotton into them. Strips of exhaust heat wrap can also be useful for masking other areas that need to stay clean, particularly along gasket joints.

PREPARATION


Without a doubt, this is the most critical part when it comes to achieving a smart-looking finish.

It seems that 400 grit sanding paper works best in most situations. Any coarser and you’ll likely be introducing new scratches instead of prepping the surface. Finer-grained sheets won’t be as effective at sanding off tenacious adhesives or previous coats.

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If you do want to redo existing shiny parts as is, it would be best to polish them off at this point. It’s usually easier to mask off the borders of finishes instead of polishing things with hardwearing coats already applied.

Where most of parts are coated with hard clear or color layers, sanding everything off may not make enough sense. You can try applying industrial paint stripper with methylene chloride formulation, one area at a time.

Once the stripper film is bubbling and just before it begins thickening too much to be readily washed off easily with spray water, you should scrub off all remaining stripper with nylon brushes.

Once you’ve carefully cleaned and sanded things down to bare metal, you can start applying primer and paint coats after everything has fully dried.

PRIMING


Here’s the part you will surely looking forward to after all the prep work. Putting engine paint on right is a fun job all right. But it’s still slightly risky, as you’re working with hazardous chemicals that are flammable.

The fumes alone could cause you to get dizzy or high, and make more mistakes as you go. So follow the instructions by spraying outside the garage or in a dry and ventilated room that’s free of dust. You can also construct a spray booth out of wood frame and cardboard boxes for next to nothing.

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Choose from quality paints with matching primers that have flameproof properties. Many who rebuild bikes like to use Duplicolor and VHT products, but there are other good brands out there.

With the first coat of primer on, it’s usually best to make sure it fully dries. For colored paints compatible with the primer, you can save a little time by applying them on primer like recoating.

So you have the quick option to let the primer dry until it’s tacky and then spray the colors within an hour. Otherwise, you can just let the initial primer cure completely and then apply the colors after a day or so. Not all primers must follow this restrictive schedule when it comes to recoating, so check the label for the recommended times.

SPRAYING


It’s really critical to get your chosen colors in several thin coatings. It’s easier to smoothen thin coatings that mostly cover the part you’re working one than it is to deal with runs on the surface from excess paint material. With really nasty runs, you’ll have to wait for the messed coat to set before sanding that offending area down to primer for another spray coating.

Just apply on a series of light coatings to avoid the problem. One rule of thumb is that if the surface being sprayed seems about to get wetted completely, that’s when excess stuff might slough into runs at some point. You can always fill in spots you’ve missed with the next light coat, so no worries.

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Do mind that once you begin putting on color coats, you’ll have to follow recoating the schedule according to the labelled instructions. You better ensure you have enough time to finish the process or else leave things to set some more until you can come back to do it right.

Tip: Practice applying several coats on metal scrap to get the hang of it, especially if it’s your first time to work with spray paints.

When the last of the colored coating have fully dried, you can then lay on some clear topcoats for a deeper hue effect. You can leave this step out if you want a flatter-looking appearance for your engine.


Finish Up

Prep involves more than half the effort here. It involves skills that you should master to achieve paintwork that you can proudly show off. With practice, you’ll eventually learn to flow these steps towards getting the smooth and pleasing finish you desire.

When other bikers ask you who painted your ride, let them know the gory details. It’s always a good thing to share knowledge about a job done well, right? Especially one that may get admiring looks on the road!

To know more about painting an engine, you can watch this video:


If you liked this article, feel free to leave comments about what you think of our quick biker’s guide on how to paint an engine.


 
Lucas Knight
 

Over the past 10 years, Lucas Knight has been a motorcycle rider. He has built up an incredible passion for travelling by motorbike and always wishes to contribute to motorcyclist community. This is the reason why he created MotorManner.com where his passion is turned into useful and interesting information to the motorcycle lover. Follow his facebook and twitter or subcribe to his website to receive more useful information in motorcycle world.

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