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What Cleaning Equipment Do You Prefer?
By Brendan Baker
When it comes to cleaning engines, there seems to be as many processes and machines to get parts clean as there are hair loss treatments. However, finding what works is what really matters to most engine builders.
Since the Environmental Protection Agency (EPA) began regulating the handling of hazardous waste in ernest, it has added to the burden of cleaning engines. And it has significantly impacted the way cleaning is approached today.
So what is it that engine builders want from their mix of cleaning machines? Simple. They want what cleans the quickest, cleans the best, leaves the best finish, offers the lowest total operating cost, and does it with the lowest possible clean up expense. But, not surprisingly, there are tradeoffs.
Most production engine remanufacturers (PERs) we spoke to in addition to being interested in effective cleaning, were interested in the fastest cleaning methods possible. Speed was a large priority, after effective cleaning. To achieve this feat many PERs employ thermal ovens and shot blasting equipment. Jet spray washers are also used by PERs, but typically only for aluminum and final cleaning following machining because they are not as fast as ovens.
"What I like most about heat and blast cleaning, for our purposes, is that I can get an engine cleaned in about an hour with this process," said one PER that builds about 80 engines a month, as well as installs about 70 engines monthly.
When speed is a big concern, engine builders prefer the heat and blast method, but note that it doesn’t automate everything. One smaller sized PER estimated his shop spends 20 minutes to a half-hour handling each engine. "It takes about that much time to load baskets and transfer parts," he said. And they still must do some hand cleaning, too. "Sometimes the oven will not get all the gasket material off and we’ll use a wire wheel and run a brush through the oil galleys," he added.
For a custom engine rebuilder (CER), though, many whom we talked to use spray washers more than ovens and shot blasters. Effective cleaning and speed are still important to them, but cost was often mentioned, too. Many CERs said they were cautious about shot blasting systems citing additional cleaning time that is required. Extra time and care has to be taken to remove all the media from galleys and other tight areas, many reported.
One CER noted that he doesn’t use blasting much because it’s difficult to ensure all the media is out of a cylinder head, for example. If the parts being blasted are porous or have small crevices or galleys, the engine builder must, of course, be sure his media removal process is thorough. However, engine builders we interviewed stated that bead blasters work fine on valves, and similar components where there’s no place that blasting media can be trapped.
We also spoke with engine builders who said that blasting and media removal was not a problem if the component part was perfectly dry. Other engine builders said they would be interested in seeing improved blasting equipment, processes and procedures and/or media for achieving complete shot removal and ensuring no engine damage would result after assembly.
Several PERs we interviewed said they now use an aqueous system for cleaning aluminum, while cast iron is still often cleaned primarily in thermal ovens. Many shops we spoke with also remain concerned about using heat ovens for cleaning aluminum.
Although we have visited many shops where engine builders clean aluminum heads successfully with heat ovens, many other engine builders remain concerned about prolonged exposure to elevated temperatures and its possible negative impact on everything from vacuum impregnation at the factory to seal porosity, to casting damage to heads comprised of various aluminum alloy compositions. It appears to us that those shops that have adequately researched heat cleaning of aluminum know how to make it work. Those shops that have not, use aqueous or wet cleaning to be safe.
One CER we interviewed says that the jet washer he uses is currently set up for both aluminum and cast iron. "It’s a solution that works for both metals but is more of a compromise," he says. Eventually he’d like to have two jet spray washer cabinets so he could make one for aluminum and the other for cast iron. "I would set up one with a strong aluminum cleaner and the other with a strong iron cleaning solution. I think that would produce the best results from this type of cleaning equipment."
Many engine builders we spoke with said they would like to see more improvements to the solutions that are available for cleaning aluminum. "It would be nice to see something that cleaned aluminum better," said one PER we interviewed. "For us, sand blasting produces the best look on aluminum, but it’s difficult to work with," he points out.
"What we do with our aqueous cleaning system works well for us because we’re installing most of our engines, but it doesn’t look very good for our carry out work, even though it has been thoroughly cleaned." Many engine builders feel that for walk-in type customers it’s just as important to have a final product that is not only clean but looks like new, too.
Painting aluminum is another option some engine builders choose, but not all like the effect. "I know that there is paint available that looks like aluminum, but we don’t really like to paint our aluminum," said one engine builder. However, not all engine builders agree on this point. "I paint all my jobs," said a CER we spoke with. His reason for doing so is because he doesn’t bead blast and he has a lot of carry out work, too. Therefore, the "look" is very important.
It’s likely that if engine builders were to become cleaning equipment designers, they would try to invent some sort of media that would do more than simply clean and degrease parts. According to several PERs and CERs we spoke with, they would like to see a product invented that would produce a nice finish as well.
One of the challenges with aluminum is that it tends to corrode and change colors when it is exposed to certain chemicals. Therefore, harsh chemicals that clean cast iron can leave a residue and discolor the aluminum. "I would like to see some kind of solvent that could do a better job on carbon or oil that has become ‘carbonized,’" one CER told us. "We’re still having to use the wire brush on the intake and exhaust ports and other areas where our jet washer has missed."
The EPA Factor
Since the ’70s, the EPA has been monitoring and controlling hazardous waste from generation to disposal. The EPA has had a major impact on the automotive industry. And for engine builders, it has affected the types of solvents it uses and how it disposes of them.
In 1987, the United States signed the Montreal Protocol agreement with 24 other nations, pledging to phase out production of chlorofluorocarbons (CFCs). The ban of CFC-113 in particular impacts the type of solvents used by engine builders to clean metal parts. Today there are many alternatives to cleaning with CFC based solvents. Aqueous based cleaning solutions are now becoming more common in today’s machine shops. However, we were also told by more than a few engine builders that the use of ovens and shot blasting media had greatly reduced hazardous waste.
"We’re very conscious of what is going on with the EPA," one engine builder told us. "We’re very careful with our waste. With our thermal cleaning we’ve been able to collect all of our dust and have it hauled away in a drum, but we still haven’t come up with the best method yet for handling what we use in our (wet) cleaning tanks." This engine builder says he currently uses a skimmer to try to skim the majority of the sludge off the tops of his aqueous cleaning tanks, which helps keep them clean.
Cost of Clean
One of the most unloved side-effects of a cleaner environment for engine builders has been the extra costs to dispose of the waste. Most engine builders have to rely on the services of companies who specialize in hazardous waste and recycling to dispose of their waste products. "It’s time consuming and expensive," most engine builders told us, many adding that they still haven’t found the ideal solution to the waste issue.
Cleaning new style engines poses a significant challenge to many shops because of their more complex designs and materials. Most late model engines use aluminum heads with an overhead cam (OHC) design, which is difficult to clean. The oil galleys in them are very critical, many engine builders told us. Using bead blasting to clean them has presented problems for many of them. "The oil galleys in these style heads have a tendency to become plugged up with sludge," one engine builder stated, "therefore, it takes extra care and time in cleaning them." Another thing that adds time to the process is having to remove the oil galley plugs in order to thoroughly get the head clean.
Time Goes By So Slowly…
Cleaning time is another area of concern for engine builders. Whether the shop is a PER with a fully automated system or a one-man CER – time is money. Even the smallest engine builders today can’t afford to place all their parts in a solvent tank and clean each part by hand. The labor costs of hand cleaning alone would likely exceed the cost of the rebuild.
Even with today’s automated jet washer cabinets and thermal ovens, it’s a fact of life that just transferring the parts from one cleaning operation to the next can take an average of from 15 minutes to a half-hour depending on the cleaning set up. Some of these processes will be repeated during the final cleaning stage after all the machine work has been completed. Engine builders we spoke with would like to eliminate this extra step as much as possible.
Some engine builders we interviewed estimate that they spend 30 percent of their time cleaning which, these days, is often times related to aluminum cylinder heads. When it comes to engine blocks, which today are still primarily cast iron, total cleaning time and cost is significantly less. "We load them (cast iron blocks) into a basket, which holds one or two engines depending on its size," said one engine builder. "Then we do a jet wash after all the machine work has been completed." Therefore, he concludes, there’s probably about an hour’s cleaning time per block, total.
For the most part, many shops we interviewed had few complaints about the cleaning equipment they use. However, suggestions and concerns were made known, as previously mentioned, for equipment improvements/alternatives the next time they buy cleaning equipment.
"The thing I’m most uncomfortable with today is cleaning OHC style engines," one engine builder told us. "We are using glass bead to clean them now. I guess I need more information on alternatives such as ultrasonic or sodium cleaning or even higher pressure spray cabinets."
Several engine builders mentioned concern over small reservoirs where the fluid could contaminate too quickly in some jet spray systems currently on the market.
Thermal, shot blast, solvents, aqueous, soda, ultrasonic, to mention a few – these cleaning systems all have a place in today’s engine builders’ shops. But what works best for a specific shop depends greatly on the specific type and quantity of parts being cleaned. And it also depends on how much a shop is willing to spend. Cleaning is a necessary evil that really has no shortcuts, either when it comes to researching what works or in evaluating the total operating and labor costs involved.
If you’re interested to know more about a specific piece of cleaning equipment you should certainly contact your cleaning sales representative and be prepared to ask questions. You should also ask for contacts at those shops currently using the equipment you are interested in.
A couple of other options are: You can go to the manufacturers’ Web sites and gather information about a specific product so you know the right questions to ask. You can also refer to our January issue Engine Builders Buyers Guide (or online at www.engine-builder.com) for a list of companies supplying cleaning equipment.
Many shops may tell you that you won’t make much money from properly cleaning engine components, but as one engine builder accurately states, "It’s cheap insurance against further problems and comebacks, which can be very costly."