Chinese Crankshafts

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Chinese Crankshafts for Corvairs, update 2/17/13. 

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Every now and then the subject of having a new crank made comes up. With a little reasearch on the Net, people find out that new cranks have been made for Corvairs. These fall into two groups: Billet cranks made in the U.S. for Corvair race cars, and cranks made in China.

In this post, I am going to speak about the latter. First, let me say that a lot of people make comments or hold very stong opinions about things they have never seen. Most people are guilty of this in one way or another, and it’s mostly harmless. However, when the subject of airplane building is at hand, I always want to listen to a guy who has first hand knowledge, because in aviation, the results of poor information isn’t always harmless. When I speak on the same subject, I am very careful to make sure that the person reading or listening is getting an accurate picture, and that they also understand the parameters of the discussion. On the subject of Chinese crankshafts for Corvairs, I think that I have a particularly informed opinion, not because I understand the engine, but because I have also seen the Chinese cranks in person, I know the guy who had them made, was present when they were inspected, followed their issues, and I know the only guy who has flown one. Follow through this story with me and get an insider’s look at these cranks, and then decide for yourself how you would feel about flying behind one.

The story starts with Brady McCormick of Washington state, about 2006. Brady is a good guy, and a heck of a good craftsman, but he isn’t an engine guy nor has he ever had any kind of aviation training. He likes the Corvair for his own aircraft, a 701 he is slowly building from plans. He buys a lot of core engines, which all turn out to be early models which have short stroke cranks. Over several months he hatches a plan to have new cranks made. He starts looking around the U.S. and finds that billet cranks cost $2500 to $3000. He finds a Web directory run by the Chinese government to direct foreign buyers to Chinese manufacturers. By contacting an agent in Taiwan, Brady finds out that new forged cranks can be made for about $1000. Brady was going to use these to build engines and also resell them to builders. Quite a plan for a guy who had never built a running Corvair engine of any kind.

The catch on the plan came up quickly. The Taiwan agent stated that she needed $30,000 to have new forging dies made, before the cranks could be made on the mainland. To get started, she offered to have 5 cranks made from billets. These could be done without having dies because billets are just machined from round stock. Brady sent a sample crank, money for 5 billets, and a large deposit on making the forging dies. At this point he honestly thought that everything was going to work out, and that he was making a regular business arrangement, just as if he were dealing with a U.S. based company. Although I had not met him in person at that point, I regularly spoke to Brady on the phone, and as I listened to his great plan, I honestly thought his money was gone and he was never going to get anything. Something worse happened. They sent him the 5 billet cranks. Encouraged by this small first transaction, Brady borrowed $30K from his father’s retirement savings and sent it to pay for the forging dies. On that day he felt he had just made a move that would make his fledgling business “Magnificent Machine,” a major player in the experimental market. The long run would show something very different had taken place.

When Brady first announced his new cranks and put pictures on the Web, it started an Internet flap because they didn’t look like normal billet cranks, and Brady was prone to making statements about them that he couldn’t back up, like “they are 2.5 times stronger than GM cranks.” This was just stuff that he read on Web sites and wanted to believe. When he encountered people who actually had a university background in strength of materials, he was reluctant to admit he might be wrong. It was a rocky introduction.

I met Brady in person at the Arlington airshow shortly after. He was very different in person than what he projected on the Web. He was modest and much younger than I expected. In 30 minutes I decided I liked him and even though I am not a fan of things imported from China, I was moved by his desire above all else to return his father’s investment. I counseled him to change his Web site and online claims, and act more like his in-person self. I invited him to Corvair College #13 and he showed his stuff to our builders.  At this show, Roy from was also a technical guest of mine. Roy took Brady aside quietly and showed him that the cranks were of marginal accuracy, and Brady should tell his source that the concentricity needed to be a lot better. Brady had two cranks that were 3.00″ stroke (instead if the stock 2.94″), Two that were 3.125″ and one that was 3.25.” To give you an idea of how much planning was missing, a 3.25″ stroke crank had the connecting rod actually hit the cam lobe on rotation. Brady had enthusiasm but not experience.

The first guy to buy a crank from Brady was Steve Makish, a friend of ours and a well known KR pilot of great experience. Steve understood that this crank was unproven, something of a test. He felt like he was a good guy for the job of test pilot. He bought a 3.00″ crank for his engine.  After the short block was assembled at Dan Weseman’s with one of his bearings, Steve took it home to finish it. This is when he discovered that the rod throws on the crank were ground almost 1/8″ too wide. If assembled, it would have marginal oil pressure. Brady was informed, and he went out of his way to fix it; the best solution was having a custom made set of connecting rods. This took many weeks.

When the engine was assembled and run, Steve did his usual extensive ground run. After a long time, something didn’t seem right. Compression dropped off, and an inspection showed that the exhaust valves were bent. Usually the only thing that can do this is putting the cam in several teeth off, something a lifelong motorhead like Steve isn’t likely to do. After some time, it was noted that the keys on the back of the crank didn’t match the ones on the flange.  A careful inspection revealed the following photos. The crank had been made undersize at the factory, and instead of scrapping it, they had made a hidden repair that had failed. Very luckily, this happened on the ground.

Above is the sleeve that was put on the crank. The stock crank has the same diameter as the outside of the sleeve. In this case, the Chinese had all the crank forces going through the thin section with threading on the inside.


The people who made this crank sold it to the broker in Taiwan who then sold it to Brady, He paid about $900 for it. I am pretty sure the shop in China that produced it had a tiny fraction of that amount of money in it. How cheap were they that they didn’t just trash this one and make another? They knew that this was going in a plane. They could read Brady’s Web site. They didn’t care, they were far away, and they were never going to get sued.

If you don’t know a lot about Chinese business ethics, you could easily dismiss this as a million to one chance of happening again. If you know a small sampling of their business culture, you will understand that this is a chronic problem in buying something from a country that doesn’t have the same ethics we do. I am not condemning the people of China, I am just pointing out that there is no rational reason to think that any businessman operating at Brady’s level can expect the kind of quality that is needed in aircraft parts.

Brady got Steve another crank and bought back all the other cranks that he had sold. He had a lot of money and time in his business, and he did listen to counsel about working his was out, but he had a gambler’s heart, and his approach was to double down on his bet. He borrowed more money and had another Chinese company make connecting rods. He ordered 500 piston blanks from a U.S. piston maker. He imported aluminum cylinders even though a number of people told him that these things would have long teething problems at best. All of this was done before Brady had built one single engine. I held a small College at his place, tried to get him to work on more modest things that would provide some cash flow. He listened while you were there, but he drifted back to his previous ways later. In the end, the Chinese kept all his money, he lost his business, his house, and a lot of the other things in his personal life unraveled. It was a long way from wanting to build a 701. It needs to be understood that he closed his doors after taking care of all of his customers. The only thing he kept was the one thing he was most concerned about losing, the thing that was probably never in jeopardy, his relationship with his father. His dad stuck with him all the way through.




One other issue has emerged with these Chinese cranks. Although they were always said to be made from billet, they don’t look anything like U.S. made billet cranks. Two people who know machining very well, particularly how cranks are made, both of whom saw Brady’s cranks in person, told me that they believe the cranks are cast steel. I listened to their reasons very carefully and I have come to agree that their argument makes a lot of sense. The Chinese are known for making millions of cranks from cast steel, it is an inexpensive process that yields a part that will work in an automotive application. The hidden defect tells me that anything is possible from China, and telling people that the cranks are billets when they are cast is not a moral problem for them. Today a Corvair car business in the southwestern U.S. advertises that they have these same cranks, and it refers to them as billets. The guy has no background in experimental aviation nor metallurgy, but he aggressively tries to steer aircraft people into buying them. No one should buy one of these for an aircraft. The Web site sells lots of untested parts, much of it sourced from the same people who made Brady’s cranks.  There is one important difference between Brady and this guy: myself and the rest of the Corvair All Stars were doing what we could to get Brady to make better decisions and be more informed. He has willing to learn. The guy in the southwest has no such inclination, he just wants to make money off builders.

Although lawyers get blamed for a lot in U.S. aviation, I am going to make the case that you don’t get to see the good that they actually do.  Putting emotion aside, think about this: Every year, countless people from outside of aviation refuse to sell products to, or work with, aircraft builders, citing the reason, “I don’t want to get sued.” Some of these people make good stuff that could be well used in experimental aviation. But a number of them make trash, or things that are not appropriate for planes, many of them have no idea of how aircraft work, and most of them have never even flown in a light plane. If those people make stuff for planes, and claim that their stuff is airworthy, they would get sued. The threat of legal action does keep good things out of the market, but it also keeps trash like the crank pictured above out also. That is unless the crank is made in China. You are never going to successfully sue anyone in China, their police state would never allow it. Their manufacturers don’t even have to consider it as a possibility. I am speaking from some level of being informed here. Friends of ours know that my brother-in-law is a partner in one of the world’s largest law firms. He is a global expert on international intellectual property, and has made countless trips to China since the early 1980s. He has said many times that you would never even get through the discovery phase of legal action against a Chinese company. The Chinese know this, and it means that they are more afraid of telling a production manager that they messed up a crank than they are of getting sued by the family of a guy who lived far away in a place they will never visit. 

On an Internet Discussion Group, a well intentioned but misinformed homebuilder stated that he felt Corvairs should be built with new crankshafts and rods like other alternative engines. He further stated that he would not fly behind an engine built with used parts. Here’s a reality check: Virtually every person reading this who has flown in a certified general aviation aircraft in the United States has flown behind used crankshafts and rods, many of which have seen more than 10,000 hours of service. The overhaul practices, including magnaflux inspection, have long proven that people can safely take to the air with these components if they’ve been properly inspected and overhauled before assembly. The Corvair is no different. There are reasons why some builders might want a different crank for an extreme engine, but just feeling that any new crank is better than a reworked original one is an argument that seemed logical to Brady, a guy with no aviation experience. In reality, the Corvair has been flying for more than 50 years, and there is a known database of tens of thousands of hours on the GM crank.

If you look at automotive crankshafts, companies like Eagle and Scat have long histories of having cranks made in China. Tom Leib is the president of Scat. I have met him in person several times. A few years ago he wrote a long article in a manufacturing trade journal about the challenges of quality assurance in Chinese manufacturing. His thesis was that you’re going to get the lowest quality they can supply until you have your own people, who are ethnic Chinese, but paid for career long loyalty to you, on site where everything is done. Post process inspection in metallurgy didn’t count in his book. He felt that only major players would make it for this reason. The numbers he was speaking of to make this arrangement possible was 20,000 cranks per year. If you read the article, you will understand why Brady’s venture, or any plan to purchase from the Chinese that could be done by people in the small scale of Corvair flight engines, would end badly. I have good reason to say that Chinese crankshafts are not a good idea in Corvair aircraft engines. As we go forward, there will always be people who bring up the subject. If they do, ask yourself, what has changed since the factors that produced the defective crank above? I don’t see the nature of Chinese business changing, I don’t see a post manufacturing inspection that I would bet everything on, and the level  of production will never allow on site inspection. For the Corvair movement, Chinese crankshafts are a dead end.

A lot of people thought my primary objection to Chinese cranks is that they were made in a communist country, where civil rights don’t exist. Other people thought that it was my bias for buying things made in America. I have said that I detest totalitarian governments, and that I make every effort not to support them economically. Yes, I have always tried to support American manufacturing and jobs for our countrymen, even before 1 out of 8 Americans was unemployed or doing work below their skill and dignity. But I can make a good case against using aircraft parts made in China to a guy who doesn’t particularly care about human rights or jobs. It is up to each individual to decide what is right for his own aircraft and the people who will fly with him while he is pilot in command.



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