In fact, it can be very difficult to make an accurate diagnosis of what’s wrong with an engine until it’s clean. You may be able to recognize some failed parts, you can often see large cracks or obvious damage, but you’re really only assuming you know what caused a failure if you can’t see for sure.
Like baseball in America, the need for cleaning in the machine shop is the one constant that has marked the passage of time. So let’s review some of the basics of cleaning in the shop.
Hot Tank Basics
The hot tank is the basic cleaning machine. Some have an agitator to move the parts inside a vat of a heated chemical solution. With enough time you get a somewhat clean work piece. If your hot tank doesn’t have agitation you need to create some. One of the easiest ways is to run an air line into the solution. Put an air regulator on it and allow about 25 30 psi to bubble your hot tank solution. This will speed the cleaning process by about 35%.
If your hot tank doesn’t have a thermometer, get one. Or at least use an infrared temperature gun to ensure your tank is about 160°F. Be sure to mix your solution correctly and periodically take a pH test to confirm that the ratio of chemical to water is right about 12 on the pH scale. Experts suggest starting weak and working up to the recommended strength. If you mix too much chemical into the water it won’t clean. In this case more is NOT better. Periodically you will need to add water, as evaporation will occur.
Use a pH Checker to test the chemical strength of your hot soak tank or hot spray machine. Compared to litmus paper and other methods of checking acidity, the pH Checker is easier to use and more accurate. It features a large digital display that is easy to read and calibration is simple.
Remember, cleaning depends on the chemical’s ability to act as a wetting agent and form micelles (A WHAT?! A micelle is an electrically charged particle built up from polymeric molecules or ions and occurring in certain colloidal electrolytic solutions like soaps and detergents. It’s a subatomic particle, having finite mass and internal structure but negligible dimensions. Pretty cool word, huh?).
The table above (Figure 1) shows you the basic concentration levels to keep in mind when using detergents.
Hot tanks are relatively maintenance free; however certain areas still need to be checked. Grease agitation joints or fittings and make sure your gas burner tube is clean on the inside as well the outside. If it’s gas fired you will also need to wire brush the outside of your burner tube. Next time you drain your hot tank, wire brush the electric heating elements to clean off the gunk, this will speed the heating process. Also periodically scoop the settled residue from the tank. There’s no need to waste cleaning solution on gunk in the bottom of your tank. Remember residue or gunk isolates and insulates.
TLC for the Jet Washer
Jet washers need maintenance too. They have a lot of moving parts turntables, pumps, water nozzles, etc. All of these components need to be maintained to provide fast, thorough, trouble-free cleaning. Jet washers use three ingredients – pressure, heat and chemicals to do their intended job.
You should completely drain and clean your jet washer at least twice a year. You may need to do it more often according to the demand you’re putting on your machine.
Drain the tank, and remove the gunk. You may need to use a scoop shovel or hoe to get all of it. Next, high-pressure rinse the inside of the machine. Remove the grates and pressure rinse the interior of the water reservoir. This is a good time to wire brush the electric heating elements and scrape or wire brush the burner tube. Take the time to clean the grates, removing old gaskets and valve stem seals.
Now remove the nozzles from the water manifold. Inspect it for material that could clog the lines and use a small diameter wire to clean each nozzle. The nozzles are great places for little bits of silicon to hide and when that happens your cleaning is not as complete as it should be. Keep the nozzles out until you have refilled the tank with water. Do NOT turn on the heat yet. Close the door and push the pump button and flush the entire manifold system. This will clean any additional foreign matter from the manifold system. Now you can re-install the nozzles.
Next, grease the turntable bearings and the pump if it has grease zerks. Grease according to the manufacturer’s recommendations. Inspect the door seals and replace if needed. Also make sure the safety limit switches are working. There’s nothing worse than having an employee open the door and get hit with a bath of scalding hot chemically treated water. Remember to have your employees dress for the job. Wear eye protection, shoulder length gloves and a rubber protective apron with rubber steeled toe boots. This will provide protection in the event of a problem.
It’s also important to wipe down the outside of your jet washer. This will give you a look at welded seams to see if there are any minor leaks that you can repair before they make your whole shop a cleaning tank.
Turn on the heating elements or light the burner tube and bring your tank up to operating temperature. Most jet washers work best between 160°F and 190°F. Mix your jet wash solution according to the manufacturer’s recommendations.
Again, it’s better to mix weak at first and creep up on the proper ratio of water to chemical. If you mix too strong the machine will not clean. Do not breathe the dust from the chemical you are using. It burns like heck and can really ruin your day. Remember, you are carbon based. It WILL clean your clock.
Remember the pH test. The ideal is 12 on the pH scale. Add chemical until you have achieved this rating. Make sure the temperature is correct. You may want to confirm the temperature with an infrared thermometer to be sure that the thermostat is working correctly. Turn on the pump and let the jet washer run about five minutes. Open the door and inspect the inside for any debris that has been ejected from the manifold system. Load the turntable with components and turn on the pump and timer. After the cycle is complete you should have very clean work pieces.
Also check the intake side of the pump for any cracks or lose fittings. It is also a good idea to check the plumbing tubes to insure no rust has eaten through the tubes. These cracks or rust holes will allow air into the pump causing severe foaming.
If you see foam, either the solution is not mixed correctly or the temperature is not correct. If you find all is well and you still have foaming, add some de-foamer.
As today’s engine builder knows, there’s no one cleaning method that will do it all. Spray cabinets and pass-through systems are good for soft contaminants, greases and oils but do little with blind holes and precision cleaning. Ultrasonic cleaning removes contamination from the inside out through countless imploding cavitation bubbles. These small cavitation bubbles have been estimated to be in the range of 10,000 psi, which does a good job removing contamination and forcing clean chemistry into small passages that other forms of cleaning will not do.
Ultrasonic cleaning systems are easy to operate. They are filled to the operating level with water and detergent and heated to the appropriate temperature. Ultrasonics are turned on when a load is being processed. Optional timers are available to automatically turn off ultrasonics at the end of a set process time. Ultrasonic tanks need to be drained and rinsed periodically depending on usage and soil loading. Bath life can be extended (especially beneficial in larger ultrasonic tanks) with the addition of a filter loop (to remove particulate) and/or a sparger loop (to skim floating soils into a separate overflow weir for disposal).
Small parts are easily cleaned in a bench-top ultrasonic tank while blocks and heads require a system that can handle the weight and mass of the parts being cleaned. Too often shops buy the wrong system thinking that if it fits it will clean. There is a great deal more to choosing the right system than just tank dimensions.
Watt density, frequency, chemistry, and part placement all play a role in proper cleaning.
An ultrasonic cleaning tank equipped with 40 kHz frequency ultrasonics and a mild detergent is most suitable for aluminum. Cast iron can benefit from more aggressive cleaning (25 kHz ultrasonics, stronger detergent) although this might not be necessary. Rinsing usually follows cleaning, and a corrosion inhibitor in the cleaner, in the rinse, or post-rinse, may be needed when cleaning cast iron or steel.
The water and ultrasonic soap should be strong enough to remove the contaminant but gentle enough that it won’t harm the parts you are cleaning. You want to use a soap that cavitates well in ultrasonic solution.. Some cleaning solutions available today are very effective at removing carbon from cylinder heads and internal hard parts without harming soft metals such as aluminum and magnesium.
Health and environmental concerns have made it tougher for shops to clean, though there are still guys out there using carburetor and brake cleaner on shop rags to clean small parts. There is a better way.
Disassembled work pieces will come out cleaner than assembled work pieces. Be sure to remove the oil gallery plugs and run a long stemmed brush through to loosen any residue prior to jet washing. Remove any big chunks of gasket material or crud by hand using a gasket scraper or wire brush.
Try to remove as much silicon as possible prior to washing. This will prevent that silicon from clogging up your nozzles. Also remove the VSIs and valve stem seals from the cylinder head. You can put the smaller components into a small parts basket and clean them with the head or block. Mark or tag all components to be sure nothing gets lost and tie down any tin ware to keep it from blowing around inside the jet washer.
When considering what type of cleaning is appropriate for your shop, consider carefully how much time you spend cleaning your parts. As one supplier pointed out recently, time is precious and anything you can do to increase productivity more cheaply make s sense for everyone.
Effective cleaning is often critical to the successful completion of manufacturing or remanufacturing. Customers like clean parts, and such parts usually perform better. The right cleaning equipment for the job can free up personnel to perform other tasks while providing superior cleaning results.
It’s like I always say, you can’t machine until it’s clean!
About the author Dave Monyhan is national sales manager with Goodson Shop Supplies, located in Winona, MN.
Cleaning Equipment Product Profiles
Safety-Kleen’s aqueous parts washers with Armakleen chemistry are available in automatic, manual or both, with features such as programmable solution temperatures and flexible metal lamps and spigots.
Armakleen’s aqueous cleaning chemistry is safe for workers and the environment. Features of this solution include: no VOC permit required (most locations); non-hazardous chemistries (MPC, MM-Dip), non-toxic; non-flammable; biodegradable; effectively cleans a variety of soils, oils and greases; safe on all metal and most plastic surfaces; rust and corrosion inhibiting ingredients; oil splitting and recyclable formulations; and long solution life.
ARMEX, developed by Arm & Hammer, a leader in bicarbonate soda technology, began with just plain baking soda and now has formulated more than a dozen unique media specifically to meet industry surface preparation requirements.
ARMEX Cleaning and Coating Removal Systems have become an effective, economical and environmentally superior method for cleaning, depainting and degreasing across the country, and around the world.
The Aerolyte Bicarbonator Pressure Blast Cabinet is designed specifically for use with sodium bicarbonate media for degreasing, cleaning, and paint stripping. Soda media is non-toxic, non-hazardous and soft, making it ideal for delicate substrates; and it is water-soluble, simplifying the process of residual media removal and disposal.
The unique patented ClearView ventilation technology provides outstanding visibility during soda blasting, unlike any other cabinet on the market.
Guspro’s GO-7272100 oven for engine rebuilders is sized for processing 3 BT-606030 baskets. The oven has the capacity to process approximately 45 (V8) blocks or 270 heads per cycle. Typical cycle time is four hours. The approximate cost per cycle is $26.88 which is based on current cost of $5.60/1,000 cu.ft. of natural gas.
The company’s smaller GO-40242OX heat cleaning oven is designed for the 1-5 man shop. It provides fast cleaning, a single block or a pair of heads will have a cycle time of about one hour. Same turnaround are offered by many of Guspro’s customers who own this equipment. Loading of 2 big block V8s with heads, or 20-25 heads is typically a 2.5 hour cycle time. Guspro says the approximate cost per cycle is $5.04 that is based on a cost of $5.60/1,000 cu.ft. of natural gas.
Graymills’ benchtop ultrasonic parts cleaning system is an industrial grade machine in a compact size for fast, efficient and thorough cleaning. Three sizes of heated and insulated 316 stainless steel tank are available to match your requirements. Its powerful 40 kHz ultrasonics have permanently bonded transducers, guaranteed for 10 years. The adjustable thermostat means the units can be optimized for a variety of cleaning requirements.
Miraclean Ultrasonics are design to meet engine builders’ parts cleaning needs and goals. Individual benchtop ultrasonic tanks are available in sizes ranging from one gallon to 52 gallons. Features include electric heat and your choice of ultrasonic frequency (25 kHz, 40 kHz, 68 kHz, or 170 kHz). Most jobs respond well to 40 kHz or the more aggressive 25 kHz (not appropriate for aluminum). Options include filtration as well as an overflow weir and sparger to skim surface soils to a separate compartment for disposal. Tanks can be used as cleaning tanks and/or rinse tanks. Static tanks (no ultrasonics) are also available in the same standard sizes.
The Miraclean Parts Washer combines ultrasonic action and a vertical agitation platform to clean small or large loads with weights up to 150 pounds or more. The platform will hold multiple baskets of smaller parts or one or more larger parts during the process cycle. The tank is equipped with electric heat, filtration, and sparging for performance optimization and extended bath life.
Washington Mills is one of the largest manufacturers of abrasives and fused mineral products in the world. It offers a rich array of abrasive grain and specialty fused minerals from its multi-plant locations. They are the only producer of Brown Fused Alumina, White Aluminum Oxide, Silicon Carbide, and Boron Carbide in North America. From macro grits to micro grits to specialty fusions, products are available in a wide range of grit sizes and are precision engineered to meet your application challenges. Washington Mills has the sizes, shapes, chemical compositions and physical properties to suit your particular industry and application. Specialty coatings, heat treatments or other surface treatments are also available.
Washington Mills has the technical skills and advanced equipment to adjust its products to your specifications. In fact, the company specializes in making materials to meet your exact specifications. If you tell them what you’re looking for in a material they can manufacture it to your exact technical specifications including: chemistry, particle size distribution, bulk density, and grain shape.