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Cleaning Aluminum Engine Components
This is an edited distillation of an interesting article found on the Internet.
How do you clean aluminum engine components, mainly exterior unpolished heads, cylinders, cases, etc., i.e. the stuff that gets really grungy and corroded from years of leaking oil, road tar, salt, bugs, and neglect?
Read on and get ready to be a real Mr. Clean. Some of this is applicable to iron, too.
CAUTION: WEAR EYE PROTECTION. WEAR SUITABLE PROTECTIVE CLOTHING AND / OR BREATHING APPARATUS AS NECESSARY. WORK ONLY IN WELL VENTILATED AREAS AND KEEP THE SOLVENTS AWAY FROM FLAME. You'll be glad you did.
Avoid getting the acids, carb cleaner, and gasket remover on anything other than what you're cleaning and dispose of used solvents, etc. in an environmentally responsible way.
1) Normal wash: Good only for removing pure dirt and light oil. Use your favorite cleaner. Dish washing detergent is good for plain old dirt. Cleaners like Simple Green or Fantastic have the ability to dissolve oil. In either case hot water goes along way to break down the crud.
2) Pressure wash: Removes heavier dirt and oil but not any corrosion. Recommended only for whole engines. Avoid spraying at any exposed seals like around the countershaft or tachometer pick off, possibly the exhaust header seals, too. OK to hit normal gaskets.
3) Dishwasher: Great for individual pieces & you get results similar to a pressure washing. Use the heavy duty cycle & the hottest water. This technique of course cleans the insides of pieces so be sure to blow air through passages to get out residual water. Consider discussing this with your spouse to minimize a negative reaction. Let her sniff the dishes that were in with the parts to see if they smell like oil.
4) Sand blasting: Sand (silica or carborundum particle) blasting will seriously remove corroded metal but leave a pitted surface. Particles may become imbedded in aluminum if air velocity used is too great and or the alloy is particularly soft. Use with incredible care especially on pieces with oil or water galleries. If you do, mask off all possible entrances carefully since any grit that gets in will be difficult to completely get out and any left in will likely destroy something in your engine.
5) Bead blasting: Small glass beads which shatter on impact clean off surface crud and leave the aluminum looking like it was tapped with a zillion microscopic ball peen hammers. Same warning on keeping grit out of passages.
6) Shell blasting: Ground up walnut (or other hard) nut shells are the gentlest of the three blasting methods. Removes crud and shallow corrosion and leaves the surface looking the most like it originally did. Note that the blasting methods are the only ones that will get corrosion off metal in the nooks and crannies.
7) Solvents: Kerosene, paint thinner, gasoline, naphtha (in increasing order of flammability). Use to remove oil, oily dirt, and tar. Use a wire brush or toothbrush to assist in getting off thick gunk. If you do a lot of this work consider a parts washer to speed cleaning of disassembled pieces.
Gunk or equivalent: Gunk combines a petroleum-based solvent and a detergent in one can. Does a pretty good job on heavy dirt and light oil. Use a heavy detergent wash to remove heavy dirt, then a separate treatment of solvent to get heavy oil / tar off, and finally a second detergent wash. This works better than trying to do it all in one pass.
Carb cleaner: This is xylene and / or MEK (methyl ethyl ketone). Good for removing paraffin that form on the inside and outside of carburetors from old gasoline. Good as a general solvent, too.
WD-40: When used as a solvent it doesn't work as good on varnish as real carb cleaner, but of course WD-40 leaves the surface protected due to the oils in it. Use it immediately after you have de-crudded a brushed or blasted surface to keep it shiny.
Hydrochloric acid: Available as muriatic acid. Takes off corrosion (not oily gunk), bubbling as it does so, but leaves the surface dark gray. Use a stainless steel wire tooth brush to expedite activity. Don't use it unless you really like this color. Avoid the fumes.
Etching formula mag wheel cleaner: Known as S-100. Also available from Honda. Comes in a spray bottle. It contains phosphoric and hydrofluoric acids and bubbles when applied. Use a stainless steel wire tooth brush to expedite activity. Avoid the fumes. Leaves a nice bright finish on aluminum surfaces that are not polished.
8) Wire brushes: You can get ones that fit in your drill and brush either circularity or radially and in different wire thicknesses. Use the softest & finest grade wire for aluminum surfaces. The wire tooth brush mentioned above can be found in the welding section of your hardware store if you don't see them in the tools section.
You can also mount a wire wheel on your grinder for small parts. Wire brushing and blasting are the only things that seem to clean off corrosion and leave the surface bright. It's a lot of work and can't get in the nooks and crannies but gives the best results. Clean surface with solvent first to keep brush from simply smearing the crud around.
9) Scotch-Brite pads: Available in about 6 by 9 inch sheets. They work well on clean, smooth steel. Use caution on aluminum unless you dont mind the scratches.
10) Aluminum Jelly: The manufacture claims it works.
11) Steel Wool: Don't use steel wool on aluminum. Tiny bits of it will break off and stick in the aluminum. These then rust and you are left with "rusty aluminum"
12) 3M metal-stripper-wheel. This is a round plastic sponge, impregnated with abrasive grit, which you chuck into your electric drill. These remove tar, paint, rust from steel frames, tanks, panels. Probably a bit too abrasive for use on alloy, though. With one of these wheels, you can remove all the paint from say, a gas tank without using any evil chemicals. It also removes surface rust, leaving you with bare metal covered with a network of fine scratches, ideal for paint adhesion. You then swab off your part with metal prep, wash it off with water, dry it thoroughly, and paint away! That new paint will stick like glue!
13) Carburetor & Small Parts Cleaner. Get the kind that comes with a dip basket. This stuff will take the hide off an elephant. Use it to take carbon off the tops of pistons. Good for carb cleaning too. Don't put any non-metallic parts in it. You just dump your castings, jets, etc. into the can, and fish them out a half hour or so later. Bright, squeaky clean.
14) Berryman Chemtool. This stuff is about as poisonous and flammable as gasoline, but it's a good cleaner. Berryman's comes in a spray can. Spray it on a grease and varnish encrusted carburetor; the stuff just liquefies and flows away.
15) Gunk spray and leave it covered over night, then scrub with those plastic scratch pads.
16) For bad corrosion or poor castings like those found on old Ducatis, first bead blast followed by 320 grit followed by 400 grit followed by 600 grit followed by Nevr Dull, but it's usually just easier to buy another motorcycle. In general, the rough cast cases clean up pretty well with some aluminum cleaner or carb cleaner solvents available at auto parts stores. Tide works OK, a brass bristle brush works really well.
17) Tide. One way to clean up really crappy aluminum cases is to use good old fashion Tide. Super saturate hot water with the Tide and soak the castings for no more than 5 minutes. Use a stiff bristle brush (do not use metal bristles) and scrub like hell. Wear thick rubber gloves as the water is hot and the mixture is caustic. Rinse the castings very well under hot water is enough. If you do not rinse very thoroughly you will see corroded aluminum very shortly. This is the best way to clean up a honed bore also. Tide is good to clean out all of the abrasives. Oil all ferrous surfaces immediately.
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Definition: Corrosion, the formation of a layer of oxide upon exposure to air / oxygen / water / etc.
Why are aluminum and magnesium used in outdoor applications where they most certainly will be exposed to a corrosive environment? The reason is that these two materials form a dense oxide layer on the surface which prohibits further oxidation. On aluminum this layer is so thin that you cant see it (apart for the metal not being shiny), but if you try to polish, you will see a gray / whitish residue on the polishing cloth, wile the aluminum part now becomes shiny again. This oxide layer is composed of aluminum oxide, an almost insoluble, very hard compound, ideal for surface protection. The same is true for magnesium, but magnesium oxide is not as good a protectant as its aluminum counterpart.
On stainless steel the same thing happens. Its protected by nickel oxide in the same way as aluminum is protected by aluminum oxide. So what's the deal with iron then? Why does the ferrous metal thing continue to rust? The problem is that there are several types of iron oxide. This is not the case with aluminum, magnesium, or nickel. These different iron oxides expand differently, leading to a porous oxide layer that is not dense like the other metals. Therefore oxygen and corrosive substances can reach the iron surface, leading to even more oxidation and on and on and on until the whole iron part is oxide.
Ever wonder why spark plugs get stuck in aluminum heads? Well, the iron or stainless plug material forms an oxide layer on the plug body. These metals are more noble than aluminum (see the list of nobleness below). The oxide from a more noble metal is a corrosive substance for a less noble metal leading to the iron or nickel oxide from the plug reacting with the aluminum in the head forming aluminum oxide and reverting the iron oxide back to metallic iron, or actually yet another form of iron oxide. This chemical reaction transfers electrons from one oxide to the other, causing the plug to stick to the aluminum head.
The solution for the above problem is copper. Copper is quite inert to oxidation that is it does not corrode much. Put some copper paste between the iron and aluminum will prevent the reaction described above from happening as copper is more noble than nickel and will not be oxidized by nickel oxide. The same thing happens to stainless steel bolts in aluminum casings so use it there too and anywhere there is exposure to water, salt, heat etc.
Edited from the Internet
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Ever wonder how those professionals get those beautiful clean, lines separating colors? Go to your local automotive paint supply store and get blue 3M plastic masking tape. It comes in several different widths. This stuff will give you very clean lines and you can shape it around curves like you would not believe. After masking along borders, such as a top color and bottom color, you then can use your generic, cheap, masking tape and paper to mask off the big sections. You can do fantastic, paint-on pin stripes, using this tape to define the borders. If your hand is not that steady, paint on pinstripes using an airbrush.
Also, to keep from having ridge lines where you are butting two colors against each other, make sure that you only put on enough of the color to get coverage. This is where using clear coat systems really makes a
difference. Since the color base coats are flat, it is much easier to see when you have gotten complete coverage, at which point you can stop. Not only is there clean separation between colors, the chances of getting runs in your paint decrease accordingly.
Paint, like oil, is affected by viscosity. Paint must be reduced to achieve the correct viscosity. Some paint systems give very specific guidelines for mixing reducer with the paint. Follow these instructions, and you will be in pretty good shape. Since a great deal of what makes up paint is solvent or reducer, it is important that the ratio be correct.
Crud in the Paint
Always run paint from a can through a filter, as you fill your paint cup. Never pour it directly into the cup. Also pour the reducer through the filter. Like a carburetor, there are very small orifices in paint guns, and they clog easily. Nothing like having to stop and clean your gun, half way through applying a coat of paint.
Use a throwaway charcoal filtered respirator to keep your lungs & nose clean. Its also a good idea to use chemical gloves, a throw away body suit, head mask, and goggles. These should be adequate, to protect yourself. Just be aware, however, that the throw away respirators start working as soon as you remove them from their sealed bags. The bags are marked to indicate the effective life of these products. All of this stuff is carried at good auto paint supply stores.
Compressors get water in the tank, when they compress air. What this means to people who are using the air supply for painting, is that you will get water in your paint, unless certain steps are followed.
If you paint a lot, you can buy an permanent incline water trap. For the occasional painter, there are traps that filter oil, water and other contaminates from the air in your compressor line. They work fine for small projects, such as repainting your gas tank. Most are transparent, and change colors internally to indicate that they are no longer working. They usually attach just before the paint gun, and can be changed in about two minutes.
If you have the money, buy Develbiss or Binks. Avoid the cheap clones. Most of these are made with poor quality and have several shortcomings.
These are - Lack of spare parts poor functionality poor construction (plastic where it should be aluminum, for instance). Look for a model that has full cast aluminum body and available spare parts. Use a detail gun for shooting bikes. The automotive size guns are OK, but more wasteful of paint, as they spray a larger area. A four inch pattern like a detail gun are about right for spraying tanks and fenders.
An alternative way of painting, assuming the part is prepped, is to hang said part on a wire and dip it into a can of red primer, hang under heat lamp, discrete distance, and when dry redip in can of enamel, repeat heat lamp trip. While it takes a rather large can for the frame, most of the smaller parts do nicely in a gallon can, and if one wants to be real authentic examine the factory paint and determine which direction they hung up the part to dry by the small droplet of paint hanging on one end or the other. No masks, no compressors etc. For bigger parts use a soft brush and flow the paint on. If an industrial enamel is used, be aware that it likely has less antioxidants and ultraviolet filters, therefore don't leave your bike out in the sun.
Edited from the Internet
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The procedure was very simple, What's required is a bench grinder with a couple buffing wheels and polishing compound. The 6" grinder will do. The job mostly takes time but the affect is stunning when the you're done. While a 1/2 hp grinder is best a 1/3 hp will due. The remaining supplies are available from a variety of sources.
The best place for buffing supplies is a specialty industrial supplier like Sandpaper of Texas. They have everything you need and cab provide advice and guidance. Sears or a complete builder supply company are other options. Buy at least 2 spiral sewn buffing wheels and one loose cotton polishing wheel. The buffing wheels are stiff spiral sewn cotton buffs. If items are really bad you might want to look into a special highly abrasive wheel called a sisal. This is a coarse buff that is used more for cutting than polishing. The polishing wheel is a loose section cotton wheel made with the same material as the sewn buffs but the leaves are not sewn together. It's much softer.
Buy a package of polishing compounds. Get at lease 2 grades. One for cutting and one for color. They come in different colors. Usually brown, black & white indicating cutting power.
The procedure is to mount the sewn buff on the grinder so that the buff threads are closed to the spin. This keeps small threads from hooking and marring the surface. Next apply the compound to the buff and then press the aluminum piece or work against the buff. Wear some gloves since the piece will get hot and might slip. You don't need to hold the work very hard as that will slow down the motor. The polishing is done by light pressure and abrasives. Keep the work moving as you don't want to dig a hole into the piece being polished.
Only use one type of polishing compound with any one buff. When you change polishing compounds, change buffs. If a buff gets too dirty, simply hold the side of a screw driver of flat edge against it to scrape off some soot and excess compound.
When you are done, you will have a lot of shiny parts but there will be a caked on greasy mess where the buff deposited some compound and residual aluminum. Don't try to wash this off with soapy water. This will only tarnish the aluminum since some soaps are caustic. Use some Simichrome polish here. As the metal is removed it turns black so don't be concerned with the color change.
When all the big parts are done you may still have nooks and crannies that need additional work. A Dremel motor with similar polishing wheels and cotton pads works good here.
Think Safety! The process throws a lot of soot around and it can be dangerous. Wear a small dust mask to keep from breathing soot. Wear safety glasses and I recommend a small face shield. Wear close fitting
work gloves. Keep your work area clean from debris and be prepared to clean it up after your done. If you can do this outside, even better. It's messy. The job can be fairly messy and a bit dangerous if you are not careful. Mostly, it's logical and common sense will dictate your approach.
Respect the power of the grinder and always hold your work so that the buff is turning away from you and you won't have a problem.
Edited form the Internet
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Disclaimer: The following information has been collected from various sources on the Internet and publications for the expressed purpose of providing NTNOA members with useful information for the enjoyment, maintenance & preservation of old British & European motorcycles. While the information is intended to be as accurate as possible it can not be guaranteed to be 100% correct, therefore the reader should use good common sense and safety before implementing any of the suggestions and ask questions if in doubt.
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