How To Clean Cylinder Heads Before Paint Motorcycle

Engine rut wreaks havoc on paint, even the paint on the hood can fade from the heavy dose of radiant heat from the hot engine below. How well exercise you retrieve that rattle-can pigment job is going to last? Nosotros take sprayed engines with spray cans, even the high-heat versions, only to run across cracks, flakes and fading in just a few weeks of utilize. Take a look at any loftier-buck build and the engines are painted up to match, but they don't fade, crack or fleck, how practise they do it? How to paint an engine so that information technology lasts is all in the method. Rather than take a chance with a rattle can, we did some inquiry to find out what the best method is for a long-lasting engine pigment job. After spending some fourth dimension talking with various restoration and custom shops, nosotros had our solution.

Painting an engine can be done either before assembly or after, it really does not matter. Our 302 block had been machined and is ready to assemble, so we just painted it up before assembly. The engine was wiped clean with paint thinner and then wax and grease remover. — Painting an engine tin be washed either before assembly or after, it really does not matter. Our 302 block had been machined and is ready to assemble, so we just painted it upwardly before assembly. The engine was wiped clean with paint thinner and then wax and grease remover.

Since the motor is not assembled yet and still has the old paint on it, some serious cleaning was needed. The plan is to soda blast the block. Baking soda is great for engine cleaning and it is ok to get it inside the engine, but keeping it out is pretty easy, so we taped up the engine. First, a couple of layers of masking tape for the base. — Since the engine is not assembled withal and still has the onetime paint on it, some serious cleaning was needed. The programme is to soda nail the cake. Baking soda is great for engine cleaning and information technology is ok to get information technology within the engine, but keeping information technology out is pretty easy, so nosotros taped upwardly the engine. Offset, a couple of layers of masking tape for the base.

Then the main cavity was covered up with newspaper, we used two layers here. The piston bores and lifter valley were taped up in the same manner. — And then the primary cavity was covered upwards with newspaper, nosotros used ii layers hither. The piston bores and lifter valley were taped upward in the same style.

There are ii bug with painting an engine – adhesion and heat. The starting time is relatively elementary to solve with hot-tanking, scrubbing or in our case, soda diggings. We spent a couple of hours tediously taping up the engine for soda blasting. In the end, the record didn't keep the soda out of the cake and co-ordinate to several soda-smash resources, is not fifty-fifty a trouble. Baking soda readily absorbs into oil and water, and the hardness of the fabric is beneath that of fifty-fifty the softest begetting surfaces, so taping before diggings turned out to be a big unnecessary hassle. If you lot are painting an assembled engine, the all-time bet for the prep work is hot soapy h2o and lots of elbow-grease.

We took the engine outside and set up the blaster. For this type of cleaning, all you want is soda. The blaster uses a mechanical dead-man valve to shut off the flow of media. While great for small projects and value, the heavy spring on the valve leaves your hand worn out. For small parts, like this engine, it worked great. Note that all of the holes in the engine were taped up. — We took the engine exterior and set up the blaster. For this type of cleaning, all y'all want is soda. The blaster uses a mechanical dead-homo valve to shut off the menstruum of media. While great for pocket-sized projects and value, the heavy bound on the valve leaves your paw worn out. For small-scale parts, like this engine, it worked bully. Note that all of the holes in the engine were taped upwards.

Because soda is very soft, tough spots like inside corners, pitted areas and edges are more difficult to blast, requiring more effort on your part. Baking soda has a hardness of 2.5 on the Mohs scale, while the hardness of engine bearings is around 6, so even residual soda left in the motor will simply be absorbed into the oil (or water) until you change it. No harm, no foul. — Because soda is very soft, tough spots like within corners, pitted areas and edges are more difficult to smash, requiring more than effort on your role. Blistering soda has a hardness of 2.5 on the Mohs scale, while the hardness of engine bearings is around 6, so fifty-fifty residual soda left in the engine volition but be absorbed into the oil (or h2o) until y'all change it. No harm, no foul.

The estrus issue is the biggest problem. The enemy of paint is heat. We have all seen how pigment bubbles up when oestrus (like from a rut gun) is applied. These are the same mechanics at work on a painted engine. In the case of rattle-can paints, no amount of heat resistance additives tin can combat cylinder head heat. The problem is that rattle can paint is likewise thick. The paint used in these cans is non-catalyzed, which means it has to rely on special solvents to cure. If you have always sprayed a cold rattle-can, you know that it takes 2 or iii times equally long for it to cure. This is because the solvents must vaporize before the paint cures. Thick pigment reduces estrus transfer, which allows the heat to build on the surface of the engine, instead of wicking to the air; just similar spreading butter on a burned finger, information technology just traps the oestrus.

11. Soda blasting leaves a residue on the metal, which must be neutralized. Skipping this step would be akin to soaking the engine is oil before painting, the paint will just fall off. We used a vinegar/water wash to clean the prepped engine. You know it is working by the bubbles. Then we installed the heads without gaskets. These are only hand tight, no torque. — Soda blasting leaves a residue on the metal, which must be neutralized. Skipping this step would exist akin to soaking the engine is oil before painting, the paint will just fall off. We used a vinegar/h2o wash to clean the prepped engine. You know it is working by the bubbles. Then nosotros installed the heads without gaskets. These are only hand tight, no torque.

Next, the engine was taped up so that the only areas we wanted painted were exposed. This means gasket surfaces and hose areas get taped. — Adjacent, the engine was taped up so that the only areas we wanted painted were exposed. This means gasket surfaces and hose areas get taped.

Traditional automotive pigment, the kind that is sprayed with a paint gun, either single-stage or base\clear, is cured with catalyst. While these paints however apply solvents, the solvents misemploy much faster than rattle-can paint, and accept an active ingredient that actually cures the paint. In base\clear formulas, the base glaze does not have a catalyst, it is instead thinned using reducer depending on the temperatures of the temper at the time of spraying. The clear coat, forth with single-stage paints, are catalyzed with hardener. The hardener cures the paint so that information technology is stable. These paints are thinner and have more fifty-fifty coverage than rattle-can paints. This works to our advantage, as the thinner the paint, the ameliorate the heat transfer.

Using a measuring cup, we mixed only enough Napa base color to fill one cup for our gun. The base is a 1:1 mix, with these cups, it is hard to go wrong. A smaller cup would have been nice. — Using a measuring cup, we mixed only enough NAPA base color to fill one cup for our gun. The base is a 1:ane mix, with these cups, it is hard to go wrong. A smaller loving cup would take been nice.

Simply what about primer? All automotive paints require primer to get adhesion right? Absolutely, if you are talking about sheetmetal. It is true that you would not desire to spray a car without primer first. For i the paint would exist splotchy from variations in the body work, just too the paint has a hard fourth dimension sticking to shine canvas metallic. An engine uses more porous materials, like cast aluminum and bandage iron. The paint won't have a trouble sticking to these materials, as long as it is clean. The main problem with primer, even bones etching primer, is that it is thicker than the paint itself. Remember, the idea is to reduce the thickness of the pigment. Then when painting an engine, go out the primer out.

The gun used for this job is a Devilbiss detail gun. The smaller tip provides a smaller fan, so you don't get as much overspray. This is the perfect gun for this job. A big gun will work too. Spraying paint on an engine requires a light touch. You want just enough paint to cover the surface without being splotchy. — The gun used for this task is a item gun. The smaller tip provides a smaller fan, so you lot don't become as much overspray. This is the perfect gun for this job. A large gun will work too. Spraying paint on an engine requires a light touch. You want just enough paint to cover the surface without being splotchy.

The engine was rotated to give access for the underside. There are a lot of nooks and crannies, these need to be reached. You could easily leave the engine like this, though the paint would require mixing with hardener before painting. It looks good, but not quite ready. — The engine was rotated to give access for the underside. There are a lot of nooks and crannies, these need to be reached. You could easily get out the engine like this, though the paint would require mixing with hardener earlier painting. It looks proficient, but not quite ready.

24. The silver metalflake was sprayed through the gun with a large 2.0 tip. We had to be careful not to put too much in one area. Once we had the metal flake on the motor, we sprayed the last coat of clear. Again, this was light but solid coat, covering all surfaces. — The silver metalflake was sprayed through the gun with a big 2.0 tip. We had to be careful not to put as well much in one area. Once we had the metal fleck on the engine, we sprayed the last coat of clear. Again, this was light but solid glaze, roofing all surfaces.

For our minor block Ford (a 347 cid stroker actually), the idea was to paint it red and add a touch of metallic flake. While the metal bit might not exist suited for a resto, the process is the aforementioned. We used a base\clear NAPA Martin Senour paint, and sprayed the engine in the shop. Keep in mind that spraying this kind of paint generates a lot of overspray, much more a rattle-can, so if you don't want it tinted engine color, cover it. If yous have the space you tin create a temporary pigment booth by hanging plastic sheeting from the garage ceiling to keep things contained. You besides need a respirator with charcoal packs. You really do non want to be breathing the vapors of this stuff. We spent almost two days prepping and spraying our engine.

Once the paint had cured, it was demasked and then the engine was assembled. Here is the finished product. — Once the paint had cured, information technology was demasked and so the engine was assembled. Here is the finished production.

Check out all the paint & body products available on NAPA Online or trust i of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more data on how to paint an engine, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Jefferson Bryant View All

A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the machine audio industry as a shop director, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech manufactures for magazines, and has been working equally an automotive journalist always since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin', Mopar Muscle, and many more. Jefferson has also written iv books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine manufactures and tech videos are produced.