This is not a story about people making mistakes, because everyone does that when they are learning, This is a story about people reading the correct way to do things, and then thinking it over, and deciding not to, because they have some rationalization like ” I think someone did that for me” or “I’m busy, I will look at that later” or “I read that once, I suspect that mine is wrong, but there is too much information on ww’s site, it can’t all be important.” I wrote this last night after working 18 hours in the shop. It has a lot of spelling errors, and we have just 24 hours before the college. I was going to take 10 minutes to correct the spelling, but thought about the guy who will later say “I didn’t set the timing because I decided the advice wasn’t any good because I am a grammar and spelling Nazi and I can’t get past that, even to learn how to save my life.” Have a nice day.


Above is Gardiner Mason’s Pietenpol. The plane was nearly destroyed in the sun n fun tornado, but he rebuilt it. It flew for years and had a condition inspection every year. It was wrecked in a hard landing that tore a wheel off, it had a number of forced landings. During the years that Gardiner flew the plane, he adamantly refused to ever set the timing with a light, he never did it. He no longer flies a Corvair, and I am glad about that. Let some other engine be blamed for his death. BTW, Gardiner flew for both the military and Delta, and has 30,000 hours, and I honestly have to say he never learned anything from me, in spite of many attempts on my part: today his engine runs perfectly in the hands of someone willing to use a timing light: Terry Hand’s 2700 cc Pietenpol engine – w/Weseman 5th bearing



I have said in countless places that every one must check the timing on their engine with a timing light before flying it. I have even said that I suspect more that 1/5 of the people who fly Corvairs never do this. Perhaps you have read this and thought I was bull shitting people….Well understand this, and read it clearly, Today, I had two people with flying planes tell me in a single day that they never checked the timing on their engines. Yes, two in one day.


Guy “A” wrote with a picture that showed a broken piston ring, and asked what caused this? When asked, he stated that he had never checked the timing, because he had bought the engine from us years ago, and just assumed that it was OK to fly it without ever checking the timing.


Guy “B” wrote to say that his plane has one flight on it that went OK. When asked, he stated that the Cowl inlets were only 3.6″, He had no EGT information, one CHT, and he never set the timing on the engine. Again he bout the engine years ago, and some how assumed that it would be fine.


Here is what is wrong with that mentality: I have said in countless places, that being an aviator is about leaving nothing to chance that you can easily check yourself. Since you have to own a timing light, and you have to check the timing at least every annual, why wouldn’t you check it before flying. “Because I thought someone did this for me” is not an acceptable answer in aviation if you are planning on living long.   If I sold you a gun several years ago, and then you left it in your barn for several years, would you pick it up and handle it without checking to see if it was loaded? Only if you were a fool. Likewise, during an engine installation, there are many ways with lifting the engine, installing baffling, wiring the ignition, that the timing could be altered. It takes only ten minutes to check……but still, people who took 5 years to build a plane, evidently don’t have that 10 minutes. I wouldn’t install a Lycoming engine in a plane and not check the mag timing. Why is this OK to do with a Corvair?


I have to ask myself why I bother to write detailed stories and organize the in this format: Engine Operations reference page if people are not going to read them. In a previous photo Guy “B” sent me a picture of his engine running on his plane, with no cowling or airbox. I have said countless times that this is totally unacceptable, the same as running a water cooled car without a radiator or coolant. Yet there was some need to do this on a brand new engine. If there was ever a time in the life of an engine not to do this, it is when it is brand new. Between this, the undersized inlets, no timing set, and no egt information, how much damage do you think was done to the engine? If the engine fails in a few hours like Guy “A”‘s engine did, please tell me if you thing that all the guys in their EAA chaperts are going to say “I can’t believe he didn’t bother to take 10 minutes to set the timing” or do you think they will say “Stupid Corvairs, what a rip off that long haired jack ass in Florida is.”


How many people are going to try this? I don’t know, but here is a story about a guy refused to buy a timing light and check the timing on his Corvair, because I had build the engine 10 years earlier, and it had been sold twice since then, moved all around the country, and put on two different planes, but he was still sure that the timing must be set correctly, because I built it a decade before. Guess what happened? He crashed the plane on the first flight, with a passenger. Understanding Flying Corvairs Pt. #6, 98% DNA not enough.


In 24 hours we are leaving for Corvair College Number Thirty-Five. Is anyone learning anything, or am I just assisting in a free assembly service? This website has 740 stories on it, including many specifically on the need to set the timing on every Corvair. Is anyone reading stories like Ignition Timing on Corvairs or When to check your timing, Lessons learned Pt#2 which contains the sentence : 1) The timing needed to have been set on installation and checked at least at each annual. Please show me where it says “unless you think someone set it for you years earlier”


Every week brings this kind of news. Last week I spoke with a guy who has been flying his plane for four years…..and he has never done a compression test. Try this, call your FSDO, tell them you don’t believe in compression tests at annual condition inspections and see how fast they revoke your repairman’s certificate your plane. Better yet, tell ask your insurance agent if your coverage is still valid if you only do part of a yearly inspection. Freedom to build homebuilts doesn’t mean that one is free from following standard procedures of aviation.


The thing that gets me the most is the guys who are the beneficiaries of some great research and writing I have done, but willingly choose not to use the information, because they don’t have the time to correct some stuff, but evidently they have plenty of time to rebuild their plane. .Example: Plane flying to Oshkosh, with the landing gear 9″ too far back. I inspected the plane in California, told them the plane had poor CG and incorrect gear location. Neither corrected. On the way to Oshkosh, the engine is running poorly, (problem later traced to certified carb) but they flew past several optional airports to get to the one where the support van was…and promptly put the plane on it’s back…and said nothing when internet people blamed the accident on the Corvair engine of course. Plane flying again now, but with Chinese rockers…..


Plane under construction for 20 years, finished the engine at a Corvair College. Made a custom and unique cowl, but never felt the need for a CHT to see if it worked, operating at 7,000′ DA, leaning the carb, but of course no EGT, inspite of the fact I have said in countless places a Corvair leaned to rough running is detonating. Main gear installed 7″ too far aft, in spite of my reports on CG….First flight last 20 seconds to loss of power.. with gear too far aft plane ends up on it’s back….It is publicly blamed on my ignition buy builders “Expert”…plane is flipped over, and proves to run perfectly on points, pilot quiets admits he never flipped the switch to the back up…Later testing shows that distributor runs perfectly on BOTH ignitions, the problem was caused by the experts wiring.


Want to know how many Corvairs have been wrecked by running out of gas? Read this: Comments on aircraft accidents, everyone on the net thought that the accident that sparked the debate was caused by the Corvair…Maybe, just maybe I already knew that the pilot was a danger….He had damaged his $35 cam gear by not reading the installation instructions, so he didn’t replace it, he chucked it in a lathe and turned the aluminum gear down to save the money….and later tried flying his plane with only 5 plugs screwed into it.


Think that was the only time a pilot flew on five cylinders? Guess again, We had a pilot who did his first several flights, but missed that he never connected the 6th plug wire….He was also doing the flights with no working charging system. Same guy later flies his plane a 601, with 4″ of lateral slop in the stick from completely slacked aileron cables. Why? because he “just had to get to his destination.”.


How about flying to Oshkosh, having 80 hours on the plane, and never having changed to berak in oil? How about the same thing with 65 hours? How often do you think those builders inspected under the cowl? What did they learn?


I could keep typing these stories for hours.  Right now, there is someone working on making my list of stupid stories one longer…Just make sure it isn’t you.



  1. William, dude…you’ve made the conversion somewhat popular. Popular by definition means people, too many people….too many because any random cross section of a large enough population shows a consistent number of fools per quantified sample – comes with the territory. Although sorry for you and the awesome work you do and have done, those people are keeping the cost and availability of cores down for the likes of me. Recommendation: don’t suffer the fools, but don’t focus on them. You’ve got good people out there and they are the ones that count.

    1. Jackson,
      Here is the core of the issue. Many of the people in the story are good men, friendly, someone you would be glad to have as a next door neighbor. The problem is that they are in a rush or they just don’t take the task seriously enough. If they were bad people, I wouldn’t give a ….. but they are humans, men I don’t want to see hurt. Getting hurt, killed or harming someone else is not an appropriate penalty for not waking up and taking this seriously, but unfortunately I don’t set the penalty structure, physics chemistry and gravity do, and they are remorseless.

      What is particularly disappointing is that the corvair movement, because of notes, the discussion groups, training at colleges and testing, has the potential to be a very knowledgeable band of aviators, but it is not even close to being lived up to and utilized.


  2. As you know, I rarely comment on anything you post. In this case, you have posted a few items related to Pietenpols, and I am the grandson of Orrin Hoopman who drew the plans back in the 1930s.

    To some it might appear that you are ranting. In my opinion, your words are “fully justifiable criticism”. The craftsmanship that it takes to make a flight worthy home built aircraft in no way supports operating it like an ignorant pilot.

    Even when it was created by his own hands, every pilot must take full responsibility for the condition of his aircraft prior to taking it aloft, EVERY SINGLE TIME HE DECIDES TO DO SO! 

    “People in a hurry to unsafe things, also tend to die in a hurry.” From: flycorvair To: Sent: Wednesday, November 4, 2015 11:46 AM Subject:

  3. Let me see if I get this right: While modern auto engines may have their spark timing set based on data from a hall effect and other sensors, and the timing is set electronically, according to programming, the Corvair’s stock timing is based on a mechanical system whose timing is advanced with centrifugal weights on the rotor shaft through the distributor.

    When the engine is not rotating, and at idle, those centrifugal weights are held close to the shaft by springs. As the engine speeds up, those centrifugal weights spread outward, and mechanically advance the timing. The weights and springs are specially selected so they reach full advance at a particular rpm. At idle, the spark timing is not as critical as at full power, because little heat or power is generated in the cylinders, so the possibility of damage is far lower.

    The distributor that William sells has a different timing advance than an automobile because the engine is operated at a far lower rpm than on a car. He selects the weights and springs necessary to provide the appropriate timing advance for aviation use. Don’t use a stock automobile distributor. You will lose power or possibly an engine if you use it on an airplane. William’s also has a second bearing, which makes the timing and durability even more reliable.

    At full or advanced power, the spark timing becomes very critical because of the heat and pressures that are generated in the engine. If the timing is not set correctly with a timing light, the possibility for detonation, backfire, and pre-ignition, breaking of rings and burning of valves, and destroying pistons. The danger of engine failure becomes very significant. It also may well not develop full power while it is still running. That is why it is important to set the timing with a timing light at a specified rpm when the weights have fully advanced the spark setting.

    If at any time the clamp holding the outside of the distributor is not tight enough, a bump of the distributor can change the orientation of the distributor, and hence, the timing. I have done tune-ups where I discovered that this clamp was not tight,and hence the engine wasn’t running right simply because someone or something had disturbed the distributor setting.

    Do not set the timing on a Corvair like you do on a certified aircraft engine. Aircraft engines with magnetos have fixed timing, and it does not change from a stopped engine to full rpm. Fixed timing leads to inefficiencies, but magnetos are very reliable and generate their own power. They are fired by points. Airplane engines are set statically, with the engine not running.

    Electronic ignitions, like Lightspeed, use electronics to determine when to fire the spark plug based on programming and engine sensors that measure things like crank position and rpm, and sometimes manifold pressure. They generate a very hot spark at a programmed, most efficient, instant, but they are dependent on external power, programming, and electronics. They do not have points.

    The Kettering (named after the man who came up with it, and also known as Delco) system on the stock Corvair, has a set of points, which must be set properly to develop a full spark, and a condenser, which reduces the spark generated across the points to prevent them eroding. It has been used on millions, if not billions of engines. It is dead simple, very rugged, and doesn’t depend on electronics to fire, and it depends on external electriical power. It doesn’t care if it comes from a battery, dynamo, or alternator.

    William’s distributors have two methods to fire the spark plugs. Originally, it had two Kettering systems,and that is still offered, but now one system is Kettering and the second is electronic, which has an even stronger spark.

  4. I used your “Evolution 1” Ignition System on my build and it worked out fine. Was very simple

  5. I don’t yet own a corvair, nor an experimental airframe on which to mount it. But I read all I can and attempt to learn so that when that day arrives, I won’t be one of the pilots W.W. writes about here. Keep preaching and thanks for sharing all you do.

  6. William, I am a motorcycle Mechanic of 35 years and I see a lot of dusty timing lights and torque wrenches in MANY shops ( admittedly I used to be guilty of this) I don’t know if this is a “human condition” thing that drives excuses such as “the modern ignitions are set and forget” or I have a calabrated elbow so torque wrenches just slow me down. As I got older(wiser) I realized that in my work I hold responsibility for others lives and doing things correctly is the ONLY way to go. Besides when I deliver a unit back to my customer knowing that it is correct and safe I have a feeling of accomplishment for a job well done. Lets all stay out of the headlines. Thank you for all you do, your words do reach farther than you know.

  7. Guy “B” has not flown yet! And Guy B plans to check his timing with a timing light as specified (even if it was not specified!) 😉

      1. Don’t use Dude B either…someone on your list is bound to have a Lebowski complex! I’ll stop now.

  8. I’m sitting at a truck stop at Fancy Gap half way to my sixth barnwell trip. I plan on learning something new this time just as I have every trip, one thing I learn at my first college ( 17 ) is SET THE TIMING BEFORE FLIGHT, this message is repeated at every college, blows my mind that people still don’t do it

    1. Dan, the mistake is common enough, that I want to say it loud and clear, again. What I want everyone to get is that there are normal people doing these things, so evidently people are prone to the “It will be alright” perspectives. This isn’t about any person’s mistakes. it is about identifying attitudes from everyday life that don’t fit in in aviation.
      See you tomorrow night.

  9. Today”s life style seems to be , “I need it now”, “I don’t want to wait” and that is a problem when it comes to lifting your ass several thousands of feet from the ground with nothing below you but your own wisdom and knowledge. Its incredible to imagine the disregard of a simple task is worth the final price! Things that make you say hmm.

  10. Operating heavy machinery, owning guns, scuba diving, and setting the timing on a corvair flight engine. All things that require training, knowledge, and a basic understanding. All things that can kill you if used improperly. The first three usually require a permit, license, or certification. Setting the timing on a certified engine is done by a licensed A&P. I think the disconnect is people don’t take the time to understand why its important, and how the timing works. How the fuel actually takes time to burn, and is not instantaneous combustion. The potential danger is not common knowledge, or visually apparent. A lot of people are visual learners and its hard to visualize what is happening inside the engine.

    They think… “The engine is running it must be fine”

  11. I worked at a local FBO while in collage and saw the mechanics performing timing checks on the magneto equipped aircraft all the time. Add to that it seems that a check of the timing would be required part of the annual inspection (What IA would sign an engine off without one ?). Given all of that I find it completely unbelivable that any pilot/owner/builder would not want to check the timing on their engine at least annually and experimental vs certified, megneto vs Points/electronic be damned, it is just pure common sense. Well maybe NOT Common Sense since so many suposedly educated people seem to lack it. Do they think that somehow the Corvair flight engine is immune to the factors that make regular timing checks in megneto aircraft such a necessity ? The timing is purly a matter of physical alignment as I understand it and if that alignment has not been welded in place it is subject to change.

    I never got to go through the process of doing the timing on my engine when it was assembled at a CC, it was late on Sunday and everyone was tired and I was exhausted. Still I plan at the very least to attend another CC before I fly the aircraft and get properly trained on the procedure. The last thing I want to do is destroy an engine (or worse) because I ommited a single, simple check to ensure the engine is ready to go.

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