“Local Expert” convinces builder to use cast pistons


When we were at Oshkosh this year, a man walked into the booth on a slow afternoon. After 20 years of doing presentations at airshows, I can say that it is very hard to predict who the serious builders are when they walk in for a look, but I can always tell in 10 seconds who is there with an “issue.”  None of these people are actual builders, they are all “Local experts” who want to tell me that they know more about Corvair flight engines than I do. Mostly, they are harmless blowhards there to complain that none of our builders respect their “advice.” But the particular guy who walked into my booth was a dangerous idiot because he had actually convinced a Corvair builder at his local airport to use cast pistons in his engine, completely against advice I have been giving for 25 years. He came to the booth to gloat over his success. In reality he had just seriously endangered the builder, and every one of the man’s future passengers, all for the sake of his own ego.


Above, BHP’s Corvair powered plane The Last Original. This plane has 800 hours on it today. It lives at Brodhead and belongs to our friend Bill Knight. Contrary to what some people think, this plane has forged pistons in it.


The builder in question is a guy I have known for years; He is a very nice guy, his Pietenpol is almost done and it is outstanding in appearance. At any grass strip, this man and his plane  would inspire confidence to allow many people to let their child take a flight in his plane. Externally, this engine would even look like one “built to WW’s specs.” But with Chinese cast pistons in it, this plane contains a very dangerous hidden flaw with a very high probability of a disaster awaiting.


Most planes that are the aviation equivalent of an IED look the part, and are presented by people who are easily recognizable as mentally ill. People understand to stay away. What makes the plane described to me at Oshkosh so dangerous is that the finish and demeanor of the builder will be very disarming. I don’t have to warn people about what to do if they meet a guy with a wild look, speaking about the afterlife and holding a grenade with no pin. This warning is about recognizing that sometimes the same grenade is wrapped in a very nice gift box, and the pleasant guy offering to let your kid look inside doesn’t himself understand the contents. All he knows is that his “local expert” (who will not be flying in the plane) assured him that he and his passengers were in no danger at all.


The dangerous idiot local expert stood in my booth and offered these reasons why he told the Pietenpol builder not to use forged pistons: 1) the cast pistons were made in the U.S., and our forged ones were made in China, 2) Bernard Pietenpol’s own plane The Last Original has cast pistons, 3) The engine only makes 70 HP so it doesn’t need the extra $80 expense (per set) that forged pistons cost. Everything this man said is a vile lie, but dangerous idiots never restrict themselves to the truth nor reality when dispensing “advice.”


Lets look at the lies one by one: 1) In reality, it is the “High Tech” cast pistons the idiot advocated putting in the engine that are made by the Chinese. Every forged piston we have ever sold was made in California, so the idiot had it 100% backwards. Every cast piston for the Corvair that I have seen for sale is a product of China. They may say “ISO-9001” on the box, but that is just printed words from a culture of corruption.


2) BHP’s own plane, The Last Original, does not have cast pistons in it. A number of years ago, Bill Knight, the owner, contacted us about upgrading the engine to my spec’s internally. The only visible external change is that the engine has our black prop hub, but internally, it is all modern stuff out of our Conversion Manual, including forged pistons. I have one of the original GM pistons in my shop, and it is in poor shape. Bill Knight made a very good call on standing the plane down until it was updated. The actual engine assembly on the update was done by Mark Petz, who was standing in the booth when the idiot was saying his lie. When I asked the idiot if he would like to personally meet the man who put the forged pistons in The Last Original, the idiot was dumbfounded.


3) Everyone who came to our booth at Oshkosh this year saw both the display engine I built and Roy’s water brake dyno.  After Oshkosh, we went to Roy’s in Michigan for a day and did a complete break in run on the display engine before delivering it to a Canadian Zenith 650 builder. Because the engine was brand new, I didn’t lean on it very hard, but the engine pulled 76.5 HP at 2,675 rpm, which is below the static take off rpm of a Pietenpol. If the idiot was counting on a modern Corvair to only make 70 HP he is very wrong. I owned a dyno for years that we ran countless engines on in public, Roy has a better one, and Mark owns an even more sophisticated one. I am sure that the idiot based his guess on nothing, because that is what idiots do.


Even if the engine was to produce only 70 HP, it should still have forged pistons. In reality, all the original GM pistons were cast, but they were vast better quality that the Chinese junk sold today. The GM pistons were all U.S. made and had a steel belt cast inside to control expansion and strengthen them. Because people flew them in the 1970s means nothing about Chinese parts today.


The great danger in using cast pistons is that undoubtably the builder is going to use our CHT limits, ignition advance curves, carb jetting. cam, rpm, spark plug and prop recommendations, which are all based on the engine having forged pistons, a requirement I have held for 25 years. It is my prediction that the builder will blow a hole in one of his Chinese pistons in the first 25 hours of operation. When he does this, he may not get back to the airport, and he may wreck the plane and get hurt. Does anyone think that the idiot will then show up and build him a new plane and pay his medical bills? And then people will say, “See Corvair engines don’t work,” neatly ignoring that Continentals with the wrong pistons in them don’t work either.


I have not included the name of the builder here, because I want people to focus on not listening to local idiots. I have said this countless times, and I have no idea why the builder couldn’t just say, “Sorry, no offense, but I am going to just follow WW’s recommendations.” After I publish this I am going to go on the Matronics Pietenpol list and state the builder’s name, and say that I do like the guy, but his engine is unairworthy.  I will do this in hopes that he will change them, but if he doesn’t, and his Chinese cast pistons fail, it will be public record that I warned him, and maybe the next guy will learn not to listen to idiots.


Above, Tom Brown’s Pietenpol, flying since 1982. It has more than 1,500 hours on it. It is often said that this plane has cast pistons in it, but we are very good friends with Tom, and he has told me that he and his dad rebuilt the engine after briefly flying it in 1982. It may have forged pistons, but if it does have cast ones, they are U.S. made ones from GM, and they are vastly better quality than any cast piston from China. This plane does not use the full ignition advance, cam nor carb jetting we use today.



It is not possible for me to express how much I detest people who will not fly in planes, but give advice to others contrary to what our testing has shown. Words like “Vermin” hardly cover it. I suggest that people read my story about how fools in aviation have an ironic way of hurting others and walking away without a scratch, at this link: Effective Risk Management – 2,903 words.


The link contains the story of a great aviator, Phil Schact, a man hugely influential on Grace’s flying, who burned to death as the direct result of an idiot’s actions. In the year that followed that accident, I spent a number of long quiet nights sitting on the front porch thinking, and came to the conclusion that I will never be a good Christian, because I was not willing to even contemplate forgiving that idiot. I understand the power of forgiveness, in my life I have been both the recipient and the grantor, but we know the real measure is can you forgive the unforgivable? By this measure, I will always fail to forgive dangerous idiots in aviation. No matter how long I live, I will go to my grave with this black mark on my heart. -ww.

10 Replies to ““Local Expert” convinces builder to use cast pistons”

    1. Tom,
      My mistake was not getting the guys name. I listened to him with growing anger for several minutes, and he clearly came to my booth just to brag that the builder had listened to him and not me. After I told him why all his reasons were not valid, and told him that I would hold him responsible for the results, he actually tried to say “we will just have to agree to disagree” and tried to shake my hand. I detest these people so much I told him to “Get the F— out of my booth.”

  1. Hi William,
    I’m sure that this will cpme as no surprise to you, but the stock, production Corvair cast pistons were also failure prone. Especially the 164 CID ones. It was very common back in those days to see pistons that separated the tops right at the oil ring location. In addition many pistons were destroyed from detonatioon that forged ones might have withstood.

    Just to support the use of US forged pistons in ALL Corvair engines.

    Bob Helt

  2. William,
    Once again people assume that similar knowledge is the same knowledge. In this case, though, this builder thinks similar knowledge is BETTER knowledge. You have spent 25 years studying and perfecting building principles yet people just don’t listen. I just don’t get it, and especially when the difference is $80.00. Eighty dollars is cheap insurance to minimize the risk of landing off field somewhere .

  3. William,
    Interesting discussion with yet another idiot. The bottom line is: $80 is cheep life insurance. I like to statistically “stack the deck” on my side. I have followed your instructions and guidance in my build and every time I read something like I just shake my head and smile, confident I am doing it the right way.



  4. Hard for me to believe any aircraft engine builder would take the idiots advice in order to save what amounts to about 1% of the total cost of the engine, is minuscule compared to the money spent on the aircraft, and just stupid when the value of a human life is considered.

    Save money on things that don’t matter. I spent $800.00 on a paint job and spent the rest under the cowling because no pilot has ever had to declare an emergency over a bad paint job!

    Dale Williams
    3.0 Corvair
    67.9 Hours

  5. Sorry to hear this. Sorry to inform you that such idiots find poor fools who will give them the other side of the equal’s sign and make an ‘equation’, WILLINGLY. More importantly, you’re too smart to not forgive. Not forgiving is taking the poison you’d like the idiot to take, and still expecting him to die. It has nothing to do with ‘feelings’, forgiveness. It’s simply following the manual and using forged instead of cast. Don’t be like an idiot…you’re far to valuable and good, and intelligent. I say those true words in respect and honor to urge you to stay on the high road you’ve been traveling all this time. Don’t let an idiot knock you off. If that’s too harsh, to friendly, I’ll understand if you block me….I hope not.

  6. What really sickens me is that when this person experiences an engie failure, few if any of the people that see it or hear about it will also get the story of how he foolishly decided to use a part that you specifically call out as not airworthy. It will be like attempts to get low cost carbs to work, just an example of how poor Corvair engines are for aircraft use. The ones that work right never get the notice. Our only hope here is that this builder comes to his senses and rebuilds the engine with teh correct parts before attempting flight however I get this sick feeling that his local “Expert” will do all he can to keep him from such.

  7. Good thing that your “success” as a Christian is reliant on God’s character not yours.. or mine.
    My advice, don’t throw “THE BABY” out with the scummy bath water.

  8. I had the help of a local expert back in 2004. When I went to Corvair College #5 in Barber, OH, I removed my heads to have the intake pipes welded on, William found that my new valve seats were staked as a method of retaining them. Had I flown this engine, I would have likely dropped a valve seat and become a statistic. Falcon heads became available about this time so I elected to upgrade. William helped me a lot. EAA Chapter 1056 August 2013 Grasshopper Newsletter held a Corvair specific talk where this same local expert is still working his magic. I told some of the members that attended to get onto Williams website or come talk to me if they were thinking of doing any Corvair project.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: