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V i r t u a l V a i r s C o r v a i r D i s c u s s i o n G r o u p |
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A Speech by Robert P. Benzinger
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Robert P. Benzinger is a Professor of Industrial Design at Arizona State University. He was Senior Project Engineer at Chevrolet during the development of the Corvair engine, Design Engineer for the Corvair Engine between 1959 and 1962, and later Staff Engineer and Chief Engineer at Chevrolet until 1970 when he became associated with Arizona State University. The following is the speech he made at the CORSA National Convention in Seattle in 1975 which held us all spellbound until late that night. We are indebted to Bob Helt for the transcript of this speech. Good evening fellow Nader Haters! Do you love your Corvair? (applause) Now I know I'm in the right place. This must be the place. I'm really pleased and glad to be here; I know every speaker says this - it's like a rubber stamp. But believe me this one comes from the heart. It's my real pleasure to be here. It brings back very pleasant, very welcome happy memories; (it) recalls happy times to me. I was very much delighted and flattered when I was called and asked to appear this evening. I was a bit apprehensive about it. But as your response indicated I knew that I was going to be among friends and there had to be a way for me to do it. We've been traveling all over the West ---- Air Streaming it. (We've) Been traveling since about the first of June. And for those of you that have done it, you know that this is the circuit where happiness is a full water tank and an empty holding tank. You know that these "Happiness Is" jokes were (popular) along about the time of the Corvair and there was one that I always enjoyed and want to recall for you now. It's the one that goes "Happiness is seeing your daughter's boyfriend jump into his convertible and land right in the middle of his guitar." Perhaps it was one of the Corvair ragtops that inspired that one. But each summer we go out and prove again that there are three fine reasons - three excellent reasons for teaching school. They are June, July and August. Of course my wife was introduced here earlier this evening. She's one of the first and one of the firmest Corvair fans. When I was finally able to tell her what I was doing, her first reaction was to say "They are finally building my car." Of course she came along with me this evening to perform some pretty important functions. First off, she kept me from getting smashed during the cocktail hour. And she may correct my English usage from time to time. And she said also that she was going to count the number of times I said "you know." And I think after it's all over she'll probably be telling me what I should have said. I guess it takes a real sense of humor to endure that one. Well on with the Holden project. The Holden project started in 1957. As I think you know, Holden is GM's Australian subsidiary. And the project began in Chevrolet's R & D department to design a 2400 pound car for Holden - or at least that was what everybody was supposed to believe. We got Holden drafting paper, Holden stationery, Holden Purchase Orders - the whole shot. Now this really wasn't unusual or uncommon. Because Chevrolet had - well at least at that time Chevrolet had designed the vehicle, complete, that was in production in GM of Australia. And they did, from time to time, some cars for Opel. So this was not unusual, and was supposed to be taken in stride. By the way, particularly those of you who have '60 automobiles know the number of part numbers that start with the number 625-well these are in the Holden series of part numbers assigned by GM. And are legacies from this sham if you will of making it a Holden, Australia project. Well the entire thing was begun, and we continued well along in the greatest amount of secrecy. Very little was around Chevrolet or around GM in terms of rumors. It was pretty well kept. All anybody knew was that engineers kept disappearing into R&D for something. They didn't know quite what but something was going on in there. We were at that time refraining from any contact whatsoever with outside vendors - that is outside of GM. No contact really with anyone outside of GM for fear of letting the cat out of the bag. The engine requirements, which of course will be what I concentrate on this evening, were pretty well defined rather early in the game. The car was styled if you will, or the image of the car was to be one of a very low profile. Flat floor. Which of course meant the tunnel had to go. There was just no place for a tunnel in this sort of a concept. This very rapidly ruled out any consideration of front engine and rear drive - the conventional arrangement. There was some time spent rather briefly, looking at, or investigating, front engine and front drive. This of course was pretty discouraging. This turns into a fairly heavy automobile, turns into a fairly expensive automobile and it still leaves you to solve the problem of what the devil to do with that exhaust system in trying to keep the flat floor and low profile on the vehicle. Well light weight, rear engine, rear drive was the only reasonable solution to fit the image that the car had to meet. The four cylinder engine was considered rather briefly and rejected because it simply didn't have the smoothness that was requisite for the American marketplace. The four just didn't have it. Water cooling of course was out. Weight, size and bulk of the engine just didn't fit either. So we rather rapidly came around to the concept; six cylinder, air cooled, rear engine but with hydraulic valve lifters. And by management decision at that time it was intended to be automatic transmission only! At that point, I think we probably had the blankest piece of paper that engine designers ever faced. You know, I'm often asked how much help we got from VW and Porsche. And sometimes asked this by people who firmly believe that Herr Doctor himself designed the vehicle, the engine, the whole shot. Actually, the truth is that zero help came from Porsche or VW. Nothing from advice and council - really the secrecy of the project forbid it. And anything like that, the cat would have been out of the bag in a hurry, with this kind of advice or council or engineering consultation, if you will. And really very little help from copying hardware. These two vehicles of course were useful to a degree by showing several things: first from Porsche, that a reasonable performance could be achieved out of this kind of an arrangement. And the confidence out of VW that it could be done in volume. Now if we get Porsche's performance and VW's volume, then we've got it. And of course these engines were also useful -the whole vehicles in fact were useful - as a baseline or reference. In the case of the engine, things like the temperature, the performance level, (and) some of the manufacturing techniques were useful for reference purposes. The Porsche, I think that you would suspect, was the more useful of the two. The VW was just plain too conservative; and forgive the expression, a bit crude. I think in those years VW's compression ratio for instance was on the order of 6.5:1 and that was pretty modest for what we had in mind, and what we felt that the American marketplace demanded. I think, rather importantly, we faced some problems that VW and Porsche just never had to grapple with by other decisions that they made. For instance with the cooling fan, placing it (vertically) over the engine where it fits the concept of the vehicle, (and) fits the room available. Rather a convenient solution to the problem. But this was totally out for us. We had to find another way - the result you of course know. The third cylinder in the head: this may not sound like it is particularly difficult, but it's all the difference in the world. With a two cylinder head, it's rather simple to dump, if you will, the exhaust immediately out with a very short fork, out the front and rear of the head and keep the center area of the cylinder head nice and cool with the incoming inlet mixture. But as soon as you put the third cylinder in that head you've wiped out all these neat ideas. Then you face the problem of dealing with heat: dissipating it, keeping the hardware cool - in a central area in the cylinder head. Another reason that rather stands out is that we were committed to hydraulic lifters. They fit the marketplace and we didn't feel that the target the car was aimed at would tolerate five thousand or less mile adjustments on mechanical lifters. That just wouldn't go! Now that too may sound like a fairly simple thing to do - stick in hydraulic lifters. With the exception that the convenient place to put the camshaft is above the crank. But with hydraulic lifters, you get them high and dry, out of the oil. To keep the lifters solid and full, and not clickity-clack on start ups, the cam really had to go below the crank. This gets you into immediate design problems with road clearance, keeping the timing gears away from the road, and so on. In the design phase, this problem turned out to be a fairly difficult one to deal with. So these problems loomed rather large and were problems that we had no guidance at all on - from VW and Porsche. I think that this is a good place to pay tribute to Al Kolbe. Al passed away about two years ago, I believe. Al, I think was the finest engine designer I ever knew. To the extent that in any organization as large as Chevrolet, you can say that any one person was responsible for, or did anything. This is difficult in a big organization simply because of the magnitude of the operation. But to that extent, Al designed the Corvair engine as he had the small block Chevrolet V-8. The small block V-8 is probably the most successful automotive engine of all time. It started out as a 265 cubic inch. It's appeared as 283, 302, 307, 327, 350 and 400 cubic inches. And if any of you have followed through the years, Ford's efforts to chase that engine - those people in Dearborn spent a fortune trying to outdo that small block V8. Finally they threw in the sponge and just plain copied the thing with the 289. You know, sometimes I get looking at Ford 289 parts and I think I'm looking at Chevrolet parts. It was late in 1957 that we had the first engines running. We used to figure that the gestation period for an engine was just about what we're used to from Homo Sapiens. It took about nine months from when you told the designers and drafting room to go until you had the design completed, experimental hardware built and the first engine running. So late in 1957 the first engine was running. Shortly after that, early in 1958, the first of the cars was on the road. These were made by converting Porsches. They really didn't look a whole lot like a Porsche when you looked close. The wheels were the wrong size and the treads were different. The whole rear end was really not Porsche, except it looked like it. We did this for the reason that they looked fairly harmless on the streets. You could drive anywhere. Nobody raised any eyebrows, except the Porsche owners who wanted to stop and talk and compare notes; ask you how you liked your Porsche or how great theirs was. About the point where they wanted to look under the deck lid, that was the time you had to go somewhere else in a big hurry. But the important thing was that we could run them on the streets and not attract any undue amount of attention. The development problems during this time were centered, as you might expect, on cooling, carburetion, and blower drive and belt; and not surprisingly at that time in just plain learning to live with aluminum. What we had to do with threaded parts. What we had to do with expansions. What we had to do to keep the bearings from falling out as the aluminum expanded. And so on down the line. I think most of these are fairly well covered in the Society of Automotive Engineers, (SAE) paper on the Corvair, (140c). I understand that this paper has enjoyed a fair amount of exposure in this group. Kind of an aside to that, that paper for many years after - and maybe to this day for all I know - was an all time record holder in terms of number of sales for SAE. I don't say that because I think it's any literary masterpiece, but it's the sort of thing that's of technical interest to practically anyone associated in the industry. And you all know what your level of interest is in it at this point. The next cars that we built were full Corvairs, at least mechanically. You've probably seen some pictures of these things. They've been in the magazines. They were rather hideous looking things. All black. Kind of bulbous, bulging, rounded corners. Only a little suggestive of the way the Corvair finally looked. They even had some phony grill work up front so that they didn't attract too much attention on the roads. This program was full of surprises as you might expect. One of the surprises was incidental to one of the black beauties. It's typical in carburetion work in running octane requirement tests, (and) in running vapor pressure tests, to disconnect the regular fuel tank and run the car from cans of special test fuel that are just carried inside the vehicle. Using quick disconnects, you can plug from one can to another. Well at the Proving Ground at Milford, Michigan, there is a 16% grade. If you have ever been on a 16% grade, you know it looks like practically straight up. Now with the tank disconnected on a rear tank, front engine car this is no problem up a 16% grade. This carburetor engineer started up the 16% grade and got about 100 feet up the hill when he realized that with the tank high and the engine low, he had a fire in the engine compartment. He was going up the hill; the fuel was just pouring out the open fuel line; and there the poor devil was - stuck halfway up the hill. He knew he didn't dare stop. That would be the worst thing he could do. He had nothing to do but stand on it and hope that it kept running until he crested the hill and then run for the fire extinguisher. Well the car was pretty much of a mess as you can imagine, by the time he crested the hill. We did salvage the thing though. It wasn't a total wipe out. But for weeks he was looking for a hole to crawl in for having tied up this valuable experimental vehicle. I suppose most of you have looked at the flywheel that goes with the manual transmission, and wondered who on earth designed that crazy nightmare. Guilty as charged! You recall of course that I mentioned that the car was intended originally to be automatic only. Well there was no provision made originally for a manual transmission - and for the flywheel and clutch of course. When reason finally returned to top management under pressure from the Sales Department, they said "You can't put this car on the road with an automatic only policy." So when it was too late to change anything, we got the orders: put in the clutch, put in the flywheel. And you'd think it's pretty easy. Stick in a piece of cast iron for a flywheel and away you go. Well we did worry a lot about whether the hub and the gear would stay pasted onto the crankshaft with all that weight hanging on it. That problem never gave us any trouble at all. It never arose in fact. But the one that did happen was a frightful noise at 45-55 miles per hour. It sounded just like a freight train was on your back bumper with a full load of cars heading up a rocky mountain grade. Just a frightful racket that would drive you out of the automobile. Well after a lot of detection from black boxes in the laboratory, we finally determined that the flywheel was vibrating about a vertical axis. A tilt vibration that was excited by the firing of the front cylinder, No. 6. A wheel that was flexible so that it would not follow this crankshaft induced vibration, also made the noise go away. So we designed this nightmare of a three piece flywheel with rivets around the periphery, and of course the noise was fixed. But this brought up another problem. In very short mileage, the flexplate in the flywheel began to crack. A neat little ring all around the bolt circle and the disk would drop off the crankshaft. If you made the thing thick enough so that it lived, the noise was back again. Make it thin enough to kill the noise and it breaks. So after running the gamut of what was metallurgically possible (all of the materials - all of which failed), we finally took the compromise. We were able to work out by a hydraulic spinning process a method to take a thick disk that's about half the diameter of the flywheel and roll it out in a tapered pattern. That's why you can see the rings around them. This gave us the thick center which let the thing live, and also the flexible periphery that made the freight train racket go away. You know in the process of this flywheel, we found we had a lot to learn about riveting. We found out that the people who make rivets don't know much about rivets. They make these funny nail like things to whatever drawings somebody sticks under their noses. But what happens to them or how they function, or even how you set them, they could care less after they disappear off their shipping dock. The riveting machinery manufacturers are a little better. They know a little bit more about it. But they operate strictly on the theory that what works is good and what don't, ain't. When you're looking for help there isn't much of it there. It's live and learn as you go. As you know the riveting operation is pretty critical. It's got to be done right. In production, the holes were line reamed with the three pieces clamped as an assembly, and they had to be clamped tight. After the holes were line reamed they were moved to the riveting operation in the same fixturing and the rivets were set. At any rate production began in the summer of 1959. I think the public introduction of the Corvair probably raised more commotion, more interest, more ruckus in the marketplace and general public than anything that's happened automotive-wise before or since. And of course the start of the controversy - both technical as well as an emotional controversy - that we really don't see any end to at this point. Shortly after model introduction, a fellow from the Chicago area who was a dealer there - a man by the name of Dick Doan- got the idea to take three Corvairs down the Pan American Highway from the US into the Canal Zone. Now maybe this doesn't sound too tough, but at that time in 1960 the Pan American Highway was no more than a line somebody had drawn on a map. It looked great on the map but there was no road there. Well he took these Corvairs and a tanker for fuel with another truck to carry supplies, spares and so on. With seven or eight men in the crew, off he went. Dragging and driving these cars over mountains, thru the mud they crossed innumerable streams and took some beautiful films. The pictures were just absolutely fascinating. Cars churning thru unbelievable amounts of mud, crossing streams, and not across them but thru them. And the Corvair can ford some pretty deep water. Much deeper than those two trucks that he had with him. He said that on the first couple of crossings, they would stop, drain all the oil and change all the lubricants. They quickly got sick of that just because of the number of streams they had to cross. In some cases they would have help from the road crews that were working in certain places. They would run a Cat thru the stream beds and clear out the biggest rocks so they could wench the cars thru. He had films of dragging these cars thru where they were totally submerged. With the roof under water they were dragging them thru streams. He said the cars weren't hurt any but you can imagine after a few weeks of this how the cars smelled. They never did get dried out. It was a fascinating trip. Some of the stories he told about the border crossings were a circus. Along with that, I've got to tell another story. A neighbor of mine who worked for an outfit called Chrysler, showed a film, to a neighborhood group. Something that Chrysler had made at Riverside. It was a perfectly nauseating bit of hard sell commercialism. I thought, by golly I'll show these guys some real films. I'll get a hold of the Doan films from the trip down the Pan American Highway and really bug out some eyes in this group. But what I failed to realize was that between the time I had seen the original films and the time I asked for the films from the Sales Department, the agency and the Sales Department had done some editing on this thing. Most of the pictures of the cars that had any mud on them - they were gone! Bright and shiny clean crossing the Mexican border. All kinds of those. When they washed the cars in Panama and cleaned them up again, there were lots of those going down the boulevards in Panama City. And all the good stuff was gone. Well it was a perfectly nauseating bit of commercial hard sell. And talk about somebody looking for a hole to crawl into. I thought I would never live that one down. This is, though, a fascinating film and I wouldn't have any idea what's happened to the original. Even the edited one isn't that bad but the original would be priceless to a group like this. Maybe some of the fellows from the Chicagoland area could do some bird dogging on it and see if there is a copy of that film around. It's worth its weight in gold. (A discussion follows that the original already is in their possession). It was along about this time, too, that we had another nasty surprise. We had a road trip out in the fall of 1959, right after introduction. Early fall, almost late summer. We had a regular circuit for these road trips. We'd take off from Detroit for Colorado Springs and climb Pikes Peak to find what disasters were there. What wouldn't idle, what wouldn't start, and what wouldn't run on top of the mountain and so on. Then we'd fix everything up. From there we'd take it down to the desert Proving Ground in Mesa (AZ) and find out what a mess had been made of the hot weather running, by what had been fixed up on the hill. Well this particular year, '59, there was an early record breaking snowstorm in Colorado. The wet sloppy stuff came down in great quantities. Well the first day the fellows ran into this, they called in and said they were wasting their time. "We can't do anything in weather like this." "Do you want us to come home?" Well you scratch your head for a while and say "No you're three days from home. Stay there and do what you can." Next day they call up complaining bitterly about fuel pumps. The cars were starving for fuel. What on earth was the matter with the fuel pumps? Well we started off on a witch hunt after fuel pumps. (We) Panicked AC. "Send somebody up." "Get somebody out there at Colorado Springs." "Find out what's going on with your lousy fuel pumps." Next day they call in hat in hand. They said "We've found what it is." it's carburetor icing." Of course when you look at the design, everything that we had done and were so proud of to keep cool inlet temperatures in the hot weather and keep the air density and power up, turns into disaster in icing weather. That one, at that time was probably the worst icing car that ever hit the streets. So panic the program again. Dynamometer and cold room running. And of course that's where the heat pipe came from that goes down between the cylinders, up thru the turkey roaster and puts some warm air up there. For those of you who had '60's and were in icing country, you knew that this was almost a fix, It handled a fair amount of the icing problems, but when you got really into the rough part of it, when it was 33 or 32 1/2 degrees and 100% relative humidity, you were likely to be shut down by the side of the road anyway. It really wasn't totally satisfactorily resolved until the complete redesign with the damper doors on the outlet which recirculated air. From then on we completely forgot about any kind of icing. Well this was a great year! Tough weather all over the country and UAW and General Motors got into a contract altercation that shut down the whole mess for three months. This shut down Engineering Operations as well, because mechanics, many of the technicians, and all of the skilled trades in the Engineering Operations were members of the UAW and were carrying signs out in front of the Engineering Center. But with problems at hand and work to be done, something had to keep moving. Milford Proving Ground and Mesa Proving Ground were working since they were non-union. All of our engines and parts were locked up behind the picket line. This was when the air-suspension cars from 1958 were in tremendous demand. These things you could load down to the gunnels, carry an enormous load in them and pump up the air bags until they came right up to level height. You could then sail out thru the picket line and nobody knew you had anything in it but the driver. And it's astonishing how much went out of the gate and in the gate in that fashion. Somebody had to build experimental engines. So the Motor Room Foreman and I popped the locks on a few of the mechanic's tool boxes and we were building engines - working twelve to fourteen hours per day. And I'll never forget that feeling going out thru that picket line, eleven-twelve o'clock at night, all alone except for the picket line. I could see in the eyeballs of everybody I went past that they were measuring me up for cement overshoes. And the Detroit river is pretty cold that time of year. Between the two of us, we got quite a bunch of engines built and of course the resultant test work that went with them. The turbocharger is not only interesting to me but it's interesting to everybody here. The work on the turbocharger really started at Thompson Ramo Woldrich (TRW) in Cleveland. They'd been building turbo-chargers for quite some time for diesel applications. Mostly for line haul operations of commercial trucking. Up to this point supercharging had been fairly discouraging for street automobiles and production automobiles. There were lots of problems with any kind of supercharging. If it was a positive displacement, you had durability and drive problems with the blower. Always had control problems, this foolishness with waste gates, combustion problems, carburetor problems, and on and on. So it was discouraging. But incidental to this usage and application with commercial trucking, TRW had developed among other things, experience and a computer program that helped precisely match the turbocharger to the engine, rather than a haphazard sort of a match. Rather than take care of the spill over and all of the problems with a waste gate, they could really then begin to match the turbocharger with the engine requirements. So we got it set up, put it on a dynamometer and began to run the thing. I wish now that I had a movie of the astonishment of the faces of everybody in that room. Astonishment first that what was supposed to happen, really did. That that kind of power was coming out of the engine. Unbelievable! And perhaps, even more unbelievable was that the engine kept on running. It didn't blow up in our faces. There was enough encouragement with this that we wanted to keep going with it pretty desperately. But it became obvious that we had some problems. First cooling. Those of you have turbochargers have probably found out that the full output of the engine can not be cooled! And of course we knew this. There was no way to cool the full output of the turbocharged engine. We just went on, I think, the reasonable assumption that the driver would either run out of road or run out of guts before the engine overheated. I think that's about the way it works out, doesn't it? Now if anybody hauls a trailer with one of those, he's got real problems. We also had combustion problems. Compression ratios had to be worked out to fit the capability. That rather strange distributor with the fixed setting and pressure retard came out of this program. We had problems with RPM. With the turbocharger, the engine would run to some fantastic RPM's. And of course, structural problems. The pistons, rods, crank and valves all were problems. The valves were a very serious problem. Years back, Studebaker had a Chief Engineer by the name of Stan Sparrow who was quite a character and quite a comedian. He once said that the automotive poppet valve was a metallurgical triumph over a mechanical monstrosity. And I think with the turbocharger we proved that he was right. Temperature checks that were run on these valves rapidly told us that the alloys that were familiar for exhaust valve use, just weren't going to make it. We were over by X hundred degrees what these materials would hold still for. Eaton Manufacturing's valve division came up with a material and method for manufacture. The material called Nimonic 80A. This was a material that was developed in England for turbine buckets in turbine engines. A nickel based alloy. No iron in the stuff at all. And this was the answer. We thought that we were home free. Everything was running great. No more valve heads falling off. No more valves turning inside out. No more holes thru them the size of a pencil. Until we lost one. It was a dynamometer engine. Of course the power suddenly dumped. Take it apart! There was a hole thru the valve head about the size of a pencil. You'd have thought that all of us had lost our last friend. Doom and gloom. Eaton, with some very fine detective work and metallurgical analysis finally doped out that one maverick bar had gotten mixed up on the stock shelves. We had one bar of another totally inferior alloy that had gotten mixed in with the run on the Nimonic 80's. Although we were all sure of it, dead certain that there was no problem, it takes a little while to get your confidence back. You're a little bit careful for quite a while on how confident you can be of this thing. But of course everything did work out pretty well with the exhaust valve. And by the way in the same process we ended up with inlet valves that are made of materials that are normally used for exhaust valves. About this same time, with the higher RPM's, we were into further difficulty with the belt drive because of the higher speeds and even the more tempting temptation to do your shifting by moving your foot on the clutch sideways instead of back and forth. This gets kind of tough on the belt. Perhaps you have not thought of it but the weight and the inertia that's represented in the cooling blower is much more difficult to handle than the actual power it takes to drive the fan. The cooling power the belt can take in stride, but it's this inertial loading from the weight and inertia in the blower that stresses the belt rather badly. Particularly on speed shifts. We had been looking for a lighter construction or some way to lighten up this blower. We worked with DuPont on a new material. This material was really brand new at that time. It was called DuPont Delrin. It was an acetyl plastic which looked like it had about the right density, had the right fatigue properties, with good strength, temperature resistance, etc. The program really came along quite well. We fussed of course about what would happen to this blower when the engine was overheated due to belt failure or whatever. If you did get the engine too hot, the blower just kind of wilted over the engine. By this time the engine was gone anyway and who was worrying about one blower. We had it released for production. We were pretty proud of things the way we gained improvements in belt-. I shouldn't really use the term belt durability, but in belt tolerance to high speed and over speed. We put one of the Delrin blowers on a turbocharged car that belonged to one of the fellows in Cleveland with TRW. He drove the thing home. Next day he called us up. Said Bob, "I don't know what I got into but just south of Toledo, I was driving away from the toll booth on the Ohio Turnpike and I started to choke and my eyes started burning." "Some kind of a gas in the car." "I don't know what it was but maybe it's got something to do with that blower you put on yesterday." It happened to him a couple of times more. We looked high and low. Searched everything. Just an enormous program to try to find out what in the devil we got. Some of the strangest theories came out of this. That it was something in the air in Toledo. That it was down wind from a plant that was doing something or another. And we ended up - I don't know whether this is going to be believable or not. We set up four cars, each with two men in it. An engineer from Chevrolet and an engineer from DuPont. We included the guy from Cleveland and took the same trip at the same time of day that this fellow had taken on his way back from Detroit to Cleveland. We had two way radios in the cars and traffic all the way. "Smell anything yet?" "Gotten anything yet?" And the strangest theories. We even imagined that there was static electricity being built up on the blower like a Van de Graff generator. Well we finally found it. This was in the winter. Was cold weather. Full heater. And of course the engine compartment with the turbocharger gets pretty warm. And he had a vehicle with a slightly over high limit charging rate on the generator. So the heat of the battery together with the overcharging rate, the battery was putting out microscopic droplets of sulfuric acid. And sulfuric acid and Delrin degenerate into a gas we know as formaldehyde. If you've ever smelled formaldehyde, and I gather some of you have, this very rapidly explains the choking, coughing and the eyes watering. Well there was nothing to do but kill it. We caught it, let's say, in the nick of time. I shudder to this day what might have happened had we not put that one blower on one guy's car and driven it from Detroit to Cleveland. I'm going to quit thinking about that! So we did then settle for die cast aluminum and the die cast aluminum blower is just about - almost precisely - the same architecture and the same design that was done in Delrin. It was rather easy at that point to convert over to die cast aluminum. In belt development along with the blower we were trying to get the absolute highest speed we could and keep the belt on the pulleys. We developed tests in the dynamometer room. We simply put the engine on a pallet on the floor, hooked up fuel and ignition to it and just ran it by jazzing the throttle with a rod. This was pretty effective. We had a particularly fine technician who had set up and learned this particular test. He could tell by eye, in fact he had only one eye, but he could tell with the good eye just when the belt was ready to flip. I remember one particular time again when I wish I had a record of looks on faces. One of the belt vendors had constructed a belt that they were particularly proud of. They had done quite a bit of work on it in their own engineering organization and were sure that it was the answer to all the problems. We had been going thru all kinds of materials for cords, for cord lathe, for belt construction, wrapped and not wrapped, cut sides, notched and various rubber compounds. You name it. They were so proud of this belt that they brought their General Manager, Chief Engineer and Sales Manager along with the engineers. It was quite a group. So we went out in the lab and I had the technician set this up on the engine. It was standard procedure to warm it up, let it run for a while, recheck the tension and be sure everything was seated in and the rough spots rubbed off. Then he would run his eyeball test to flip it off. Well these fellows were watching the warm up and the technician had it right to the edge of coming off. He knew just when to back off. These fellows were pretty proud of themselves. They were all set to "pop the champagne" when the technician looked at me and said, "Should I flip it off?" So I looked at the fellows from the belt vendor and said, "Are you ready?" A few of the looks started to pale. I gave him the nod and just like that the belt went off. And these fellows, well you can imagine ... dragging their tails behind them. I'm often asked why we didn't try a steel cord belt. Steel ought to be a good material. Strong! And it is. Steel isn't a bad material for making the cord in belts. But if you ever saw one come off or one break, you know this is the way to destroy the whole rear end of the vehicle. They really do make a mess when they come off. We wanted rather desperately to match up a turbocharger with an automatic transmission. It has some pretty attractive aspects about it. But we just could never make it go. The thing that you run into - and maybe some of you have even experimented yourself with this combination - is that when you wind up the engine in low gear, get the turbine wound up to full boost and then make the upshift, it suddenly pulls the engine RPM down with the boost still up where it belongs for a couple of thousand RPM higher. With the low engine speed and the blower still wound up, it gets into combustion difficulties that makes wild detonation look pale. There was just nothing we could do to get the engine thru this rough spot. Once the malcombustion starts, you can't just shut it off again. Perhaps the availability of a three speed automatic or maybe a four speed would have done it by getting the gear steps tighter. But with Powerglide being a two speed set up we could never find anyway around it. I do have some pleasant recollections of some of the early testing and early driving of the turbocharged vehicles. You know on the roads around the proving grounds it looked just like any other Corvair. But some of the astonishing things it would do to people who didn't know what was in the back end. On the same 16% hill I was talking about before with the carburetor fire, I pulled up to the hill one day with one of the early turbocharged jobs. There was a Cadillac right ahead of me with two engineers in it. They kicked off up the hill with a great commotion and a great whoosh. I let them get a little ways and then kicked off with the turbocharger. It seemed like it was about three car lengths and I passed that Cadillac like it was chained to the road. Going up that 16% grade, that must have been totally absolutely incomprehensible to these Cadillac engineers. They just wouldn't believe what was happening to them. I see time is getting on here. This is kind of a hard one to summarize and conclude. I guess the record is clear for GM. As far as GM is concerned, the Corvair went down the tubes. And amid some circumstances that were plainly embarrassing to General Motors. You won't find anybody on the payroll there that wants to repeat the experience. And as surprising as this sounds, there was rather little opportunity on the part of General Motors to do any rebuttal. I don't know whether any of you are familiar with Don Campbell. He's a syndicated financial columnist. I have here his column from 26 July 1972. I think he summarized it in words that I'd like to share with you now. He goes thru a fictional scenario of product difficulties. I'll pick it up midpoint here, quoting Don Campbell.
I'll skip a bit here and quote again.
I think perhaps the best overall appraisal of the decline and fall of the Corvair from production, was printed in a British magazine, Autocar, in their issue of 10 July 1969. It was rather impartial and taken from an objective point of view. It was about a four page article as I recall. I commend it to your reading if you've not had the opportunity. The best overall vindication of the Corvair, I think, is in the undocumented, but indisputable, fact that among GM people - employees, executives, engineers - the Corvair was probably the most popular personal and family car that GM ever built. For my part, I find a lot of things I can be proud of. I had a lot of fun doing it. I certainly don't want to say that there aren't some things I wish I had the chance to do over again. But I'm very much pleased looking back on it and I'm pleased to have shared some of the experiences with you this evening. I certainly want to wish all the luck and success in the world to this fine organization (CORSA). I see that it is well led and enthusiastically followed. My best of luck to all of you in this fine organization. |
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If there are any questions and if your time schedule permits now, I'll be pleased to answer those that I'm able. Q. Have you ever considered writing your Corvair memoirs into a book? A. That sounds an awful lot like work! No I haven't. I don't know who said it. Somebody of the cut of Edison or Steinmetz. He said that most things that are worthwhile degenerate into hard work. Q. In your discussion of the flywheel you covered rather thoroughly the spring plate of the flywheel, but you didn't say anything about what the third plate is for on the outside of the riveted assembly. A. That's to get more weight, more mass into it. You know the smoothness of the engine is in some measure dependent upon the weight - at least a threshold, a minimum amount - you can put into the flywheel. And without that extra weight on the outer ring, we didn't think we had enough. Q. A question was asked about a maximum turbocharger RPM. A. I'm scared to throw out a number. It's a far different day than when you could say, "Well it died." "Send somebody over to pick it up and bring me another car." I'm afraid of a number now as dear as parts are to all of you. Lots of luck with whatever you can get out of it. I'd rather not get into that one. Q. I was wondering. You covered the story of the rivets in the flywheel. One of the more popular fixes for the shoddy rivets is to weld the darn thing. Why didn't Chevrolet do that in the first place? It would have been much cheaper. A. I can say on that, I honestly don't remember. I suspect as you stated, and as the snickers here indicated, that's a fairly obvious approach. Certainly between the flexplate and the weight there is no great difficulty, but welding it to the cast iron would present a problem. We might have gotten away from it, but I honestly don't remember if that was considered. And if so, how seriously. Q. A question was asked about a more efficient intake manifold in getting the engine to breathe. A. You remember what the '60 looked like. With a cover plate over the top. One of the reasons we wanted to get rid of that loose cover plate is again, that it was a barrier to controlling the temperature of the carburetor flange. It was another gasket and another barrier in there and we regarded it as a piece of progress that we were able to make the manifold integral. We got rid of a piece which was economy and also got one more tool to control the temperature of the throttle body and the temperature of the carburetor. There are a fair number of conversions that just mill off various amounts of the manifold and then build back something that may be regarded as more desirable. I think Bill Thomas on the West Coast was doing quite a bit of that. Q. A question was asked regarding the direction of rotation of the Corvair engine. A. When you figure out the direction of wheel rotation back thru the hypoid and gear train this is the way it comes out. I guess I don't like the snickers that went with it because that answer was not a put-down. It was that obvious to me. In running the power clear thru with this long quill shaft is where you get the reversal. Q. Isn't it true though if the ring gear were on the other side of the pinion, the engine could run in the opposite direction? And if you wanted to go mid-engine you could turn the differential upside down and your direction is still correct. You could turn the whole engine assembly around and put it in front of the axle. A. As soon as you get the engine in front of the axle you are back to conventional rotation. Is that what you mean? Q. No. What I'm saying is you take a conventional Corvair transaxle, cut the bell housing in half. Turn the differential over. Weld it back together and install it with the engine in front of the axle and you go the right way, with the Corvair engine turning the standard direction. Another way of saying it in a general sense is if the ring gear had been originally designed for the differential on the opposite side of the pinion, as what exists now, then the engine could have turned in the conventional direction. A. The only thing I can say is that it's late and I'm a bit far gone. I wish I could pursue it with you but it's beyond me tonight. Sorry. Q. Did Bill Thomas have an influence on the design of the 4X1 heads? A. We were aware of what Bill was doing, and Bill was a frequent visitor at the Engineering Center. We liked Bill because he was easy to get along with and we could speak each other's language. This wasn't the case with many people who were in that sort of a business. Bill was a frequent visitor and well liked at Chevrolet. He did nothing you could put your finger on but people are always influenced by the other people they come in contact with and the things that they are doing. I think we can say this honestly without saying we leaned on Bill for what to do, or so on. It certainly was an influence. This brings up a kind of a sore point with me. I'll share it with you. I think Chevrolet's top management made an error in judgment on many of the things that happened in the high performance image of the Corvair. We spent an awful lot of time chasing fuel injection, chasing all those things that would relate to the enthusiast's impression of high performance. And we spent an inordinate amount of time, resources and valuable engineering talent in chasing a piece of the market that was really rather fickle. That jumped from Corvair to Mustang to Corvette to ... you know. Fickle is the right word. In the mean time I think we neglected some of the things in the Corvair that would have appealed to a more stable portion of the market; to wives, the families who were looking for the handling and reliability in terms of wet and sloppy weather. It was one of the things I was a bit peeved with. By mentioning it tonight you see, I'm still a bit peeved. I think we spent too much time, too much effort. Squandered too much in terms of resources chasing a performance image that just plain wasn't in the cards. The horses weren't there to begin with in this concept of a vehicle. Q. Does that also explain why a solution was never found for the seals on the pushrod tubes? Somewhere else I had noticed that you had made the statement that you didn't realize that it was a problem. I don't profess to know that much about the Corvair but I would have felt that the problem would have come up at Milford, in all those miles that must have gone on at that track. Those things must have started leaking somewhere there. A. I guess I can repeat it. That it does kind of mystify me to this day. We didn't have that much difficulty with the pushrod tube seals. Inorganic parts, rubber parts, these are real touchy. You're at the mercy, as we were, of the honesty of the parts supplier. There are an innumerable - literally an infinite - number of rubber compounds possible. Some of which do the job, and most of which do not. It's one of those things we had to watch very carefully in terms of quality in terms of integrity really of the guy who made it. There are an awful lot of people who are selling after market parts. You have to make your own judgment on their individual integrity. I still feel that carefully handled the problem is minimal. Now there is no getting away from it. 0-rings are touchy! The bore that receives the things has to be clean. No nicks. No burrs. It only takes a very slight scratch in the surface of the 0-ring to spoil the seal. They are also sensitive to being properly lubricated when they are installed, If the things roll or rotate any in the groove, the ball game's over, It's going to leak. But with the right material and reasonably careful lubrication and installation, there should be no problem. We had darn little problem with them. Q. What did you use to lubricate them with when you installed them? A. Lubriplate. Engine oil is pretty good. But Lubriplate is what we used at Tonawanda. Q. Due to the similarity of the Pontiac Tempest transaxle and the great deal of similarities in that particular drive train, was it developed to coincide with the Corvair at the same time? And will the ring and pinion fit the different models? A. I don't know if the ring and pinion will fit. And as far as things went, at least in those years, General Motors ran its affairs so that the producing divisions were totally independent of each other. They carried on their own engineering at different locations. A totally different group of people. Different leadership. Different policies at the top. That doesn't say that we were forbidden to speak to each other. But whatever Pontiac did, they did because they wished it that way. They weren't lead into it by the availability of parts from another division. So you'll have to ask Pontiac about that one. Q. A question was asked about why the original turbocharger intake manifold with the six legs was not put into production. A. You mean with six legs out of a plenum chamber? (Yes) In the development, we had an unbelievable number of manifolding combinations. We had one person in the organization, who I won't name, but who believed that plenum chambers were right! That the discharge from the compressor should go into a plenum; and then off the plenum, take various combinations to preserve mixture and so on. The plenum chamber just turned out to be a disaster. It was too much surface to begin with. Most of the plenums had some kind of a sump in the bottom. And what happened is that the sump just filled up to the spill over point with liquid. Even on a dynamometer it was unpredictable which way it was going to slosh. It would just destroy any maintenance of uniform mixture. So we fairly rapidly determined that the way to preserve some kind of mixture distribution was that from the blower outlet, from there on, everything had better be down hill. Nothing to pocket, catch or puddle. So it was its own disaster and died for that reason. Q. One problem that a lot of Corvair owners have had is the problem with valve seats. You have the problem mostly with 140 HP heads. A. You mean with the seats coming out? (Yes) This of course can happen for such a variety of reasons that it really isn't reasonable to answer "blanket." One of the ways it can happen, and can happen with say the best of hardware, dimensionally, mechanically and metallurgically is after a hard run when everything is good and hot, like mountain driving, you come to a long downgrade which quenches and cools down the valve seat while the cylinder head is still hot. We have seen some cases where the valve seat will play "Ring Around The Rosy" on the valve stem, simply because of that temperature differential that quenches the seat while the head is hot. The rest of them from there - with everything right, dimensionally, metallurgically, and properly installed - should hang in there pretty tight. That's saying a lot I know, to say if everything is right. We put the seats in as tight as they would go. What happens if you try to put them in tighter is that the aluminum or valve seat, or both, will be overstressed and it will relieve back to the interference fits that were specified in the first place. So putting them in overtight really doesn't do anything. Material yields to get it down to that limit anyway. Thank you very much. |
