Chevrolet Corvair

The Chevrolet Corvair was an automobile produced by the Chevrolet division of General Motors from 1960 to 1969. The Corvair was offered in a wide range of body styles, including a four-door sedan, coupé, convertible, station wagon, pickup, panel van, and a window van called the Greenbrier. The Corvair — like the Ford Falcon, Studebaker Lark, Nash Rambler, and the Plymouth Valiant — was created in response to the small, sporty and fuel-efficient automobiles being imported from Europe by Volkswagen, Renault and others.

The Corvair was part of GM's innovative A-body line of cars, but this was by far the most unusual, due to the location and design of its engine. It was a rear-engined vehicle in the style of the Volkswagen Beetle and the Porsche 356 Speedster, which was unusual for American cars at the time. The entire product line initially shared an aluminum, air-cooled 140 in³ (2.3 L) flat-6 engine. The first engines produced as little as 80 hp (60 kW), but later developed as much as 180 hp (134 kW).

History

The Corvair name originated as a fastback show car in 1954, which, like many Chevy concept cars of the period, were based on the Corvette, including the Chevrolet Nomad and Chevrolet Impala. The design was championed by Ed Cole, Chevrolet chief engineer in the early 1950s and general manager in the late 1950s, as an answer to the growing popularity of small, lightweight imported cars.

Design began in 1956 under the auspices of Ed Cole, and the first vehicles rolled off the assembly line in late 1959 as part of the 1960 model year (in which it was named Motor Trend magazine's Car of the Year).

For 24 hours, the Corvair was tested at the Riverside International Raceway in Riverside, California, one car did a roll but the other did the 24 hour drive and only lost a quart (1 L) of oil (Source: Riverside Raceway Palace of Speed by Dick Wallen).

The early 1960 models were conceived as economy cars, and had boxy styling, basic trim, and few amenities to keep prices down despite the relatively expensive and unique powertrain. A novel feature available for two-doors was a fold-down rear seat, included on some higher-level models. Passenger compartment heat was supplied by a gasoline heater mounted next to the spare tire in the luggage compartment. The line quickly grew from plain, four-door sedans with bench seats (the base 500 and slightly more upscale 700) to the Monza 900, a two-door coupé with bucket seats and plush trim introduced late in the model year. Optional was a more powerful engine rated at 95 horsepower, thanks to a more radical camshaft and low-restriction exhaust. Despite its late introduction, the Monza sold 12,000 copies, making it one of the most popular Corvairs.

1961

For 1961 Chevrolet added an optional four-speed manual transmission to augment the standard three-speed manual and optional two-speed Powerglide automatic. The Corvair engine received its first size increase to 145 in³, courtesy of a slight increase in bore size. The base engine was still rated at 80 hp (60 kW) when paired with the manual transmissions and 84 hp (63 kW) when mated to the optional automatic transmission. The high-performance engine was rated at 98 hp (73 kW). To increase luggage capacity in the front, the spare tire was relocated to the engine compartment, and the gasoline heater was replaced by a system of ducts that redirected warmed air from the cylinder heads to the passenger compartment. The gasoline heater remained available as an option through 1964.

A station wagon, the Lakewood, was also added to the lineup in 1961, and it contained a total of 68 ft³ (1.9 m³) of cargo room — 58 in the main passenger compartment, and another 10 in the "trunk" under the hood. Engine heat and gasoline odors migrating up through the floor of the station wagon proved to be a persistent problem, and the wagon was relatively short-lived.

That same year, Chevrolet also introduced the Corvair 95 line of light-duty truck, which used the Corvair driveline and were forward-control, with the driver sitting over the front wheels, as in the Volkswagen Type 2. The Corvan model was available in a myriad of configurations as both a panel van and a window van. There were also two models of pickup available. The Loadside was a fairly typical pickup of the era, except for the rear engine, forward controls, and a strange pit in the middle of the bed, The more popular pickup was the Rampside model, which, as its name implies, had a large fold-down ramp on the side of the pickup bed. Rampsides were used by the Bell System because of the ease with which cable reels could be rolled in and out of the bed.

The Greenbrier Sportswagon used the same body as the Corvan with window option, but was marketed as a station wagon like the Lakewood, and was available with trim and paint options similar to the cars, arguably making it the first American Minivan.

Continuing from the end of the previous year was the Monza, heavily promoted and sometimes considered "the poor man's Porsche." The Monza was expanded to a four-door as well as a two-door coupe, and garnered around 144,000 sales.

The first Corvairs (1960 – 1964) were factory equipped with an ignition lock wherein it was possible to start the car and then remove the key.

1962 – 1963

In 1962, Chevrolet introduced the 150 hp (112 kW) turbocharged Monza Spyder, making the Corvair one of the first two production automobiles to come with a turbocharger as a factory option, with the Oldsmobile F-85 Turbo Jetfire of the same year. The Super Deluxe Monza Spyder introduced improved brakes and suspension, and a multi-gauge instrument cluster which included a tachometer, cylinder head temperature gauge and intake manifold pressure gauge. A convertible option was added as well. The 1963 model year saw the end of the Lakewood station wagon and Loadside pickup, and the availability of a long 3.08 gear for improved fuel economy, but the Corvair otherwise remained largely the same as in 1962.

1964

Significant engineering and safety changes occurred in 1964, while the bodies and models available remained the same.

The lineup remained relatively unchanged for the 1964 model year, with the exception of the engine growing from 145 to 164 in³ (2.3 to 2.7 L)due to an increase in stroke; the base power growing from 80 to 95 hp (60 to 70 kW), and the high performance engine growing from 95 to 110 hp (70 to 80 kW). The Spyder engine remained rated at 150 hp (112 kW)despite the displacement increase of the engine. The Rampside pickup was discontinued at the end of the model year.

1964 also saw a critical improvement in the Corvair's suspension; the car's swing axle rear suspension's tendency to lose traction suddenly and without warning when pushed to the limit was tamed by use of an additional transverse leaf spring coupling both rear wheels. The change was insisted upon by new Chevrolet general manager Semon "Bunkie" Knudsen, who according to contemporary John DeLorean had to threaten to resign in order to get the change approved.

However, a young lawyer named Ralph Nader had written a book called Unsafe at Any Speed in which the 1960-63 Corvair (and its purported greater tendency to roll over) was used as a dramatic case study. Even though a 1972 National Highway Traffic Safety Administration safety commission study ultimately exonerated the Corvair and declared it no more unsafe than any similar vehicle of its era, Nader's book, which was published in 1965, dealt a severe blow to sales of the Corvair line. The sporty, inexpensive Ford Mustang, based on the conventionally designed Ford Falcon and introduced in late 1964 in response to the Corvair, ultimately finished off Chevrolet's bold experiment.

1965

A dramatic redesign of the Corvair body and suspension and several powerful new engines came in 1965. The new body style lay somewhere between that of a baby Chevrolet Corvette Stingray and a mid-1960s Italian sports car and foreshadowed the 1967 Chevrolet Camaro that eventually replaced the Corvair. A new fully independent suspension similar to that used on the Corvette replaced the original swing axle rear suspension.

The previous 150 hp (112 kW) Monza Spyder was replaced by the normally-aspirated 140 hp (104 kW) Corsa and the 180 hp (134 kW) Corsa Turbo. The Corsa came standard with an instrument panel featuring a 140 mph speedometer with resettable trip odometer, a 6,000 rpm tachometer, cylinder head temperature gauge, analog clock with a sweeping second hand, a manifold vacuum/pressure gauge and fuel gauge. Also standard was a short throw shifter for the manual transmission (no automatic was offered). The standard equipment Corsa 140 hp (104 kW) engine was notable for the fact that the engine used 4 single-throat carburetors, larger valves, and dual exhaust — the factory's response to a modification which hot-rodders had been making since the car first appeared; it was available as an option on other Corvair trim levels. The base 95 hp (71 kW) and 110 hp (82 kW) high performance engines were carried forward from 1964 for the 500 and Monza models.

By this point, the more utilitarian station wagon, Panel Van, and pickup body styles had all been dropped in favor of the sportier coupe, hardtop sedan and convertible styles. 1965 would be the last year for the Greenbrier window van, which was retained only because of a few fleet orders, with less than 2000 being built. Chevrolet replaced the Corvair-based vans with the Chevrolet Sportvan/GMC Handi-Van, which used a traditional front engine/rear drive axle borrowed from the Chevy II.

1966 – 1969

The 1966 lineup remained essentially unchanged from 1965, and sales began to decline as a result of Nader's book, the popular (and cheaper) new Mustang, and rumors of the upcoming Camaro. The sales decline was also accelerated by a decision at GM to discontinue further development of the Corvair. One change of note was a more robust 4 speed synchromesh transmission for 1966, using the standard Saginaw gear set used by other GM vehicles. The new transmission was capable of handling more stress, though generally wasn't as smooth shifting as the earlier transmission. Also, the gear ratios were carried over from other GM cars, and were not optimal for a street-driven Corvair. A small flexible plastic air dam was installed below the front apron to alleviate problems with front-end lift at high speeds. It is a popular retrofit to the 1965 models both for functional and aesthetic reasons.

In 1967 the Camaro was introduced and the Corvair line was trimmed to the base 500 sedan and coupe, and the Monza sedan, coupe and convertible. The 140 hp (104 kW) and 180 hp (134 kW) engine options were deleted as well, although the 140 hp option would be later reintroduced as a Regular Production Option and would remain available until Corvair production ended.

In 1968 the line was trimmed even further to just the coupe and convertible, and sales were down to 15,400. This model year was the first equipped with true collapsible steering columns, a final response to one of the most valid safety criticisms.

Corvair production finally ceased in 1969 with sales of only 6,000 cars, a victim of Nader's book, Ford's Mustang, and Chevrolet's own Camaro and Nova. Although negative publicity hurt the Corvair, ongoing litigation is believed to have extended the production life of the vehicle, as ending production would have been construed as an admission by General Motors that the product was flawed. According to researchers such as noted GM historian Dave Newell, GM had already planned on ceasing Corvair production after the 1966 model year to make way for the Camaro. But the timing of Nader's book turned out to be an inconvenience. Not wanting to appear as though they were buckling to Nader's pressure, GM kept the Corvair in production for another three years. The only developmental changes made were to keep in line with government safety and emissions requirements. Unfortunately, such efforts have not kept the "Nader killed the Corvair" myth from flourishing. The Corvair was already dying; Nader just came along to pose with the corpse.

In what may be the automotive industry’s greatest irony, the NHTSA –the federal agency created from Nader’s “consumer advocacy”- investigated the Corvair and issued a report in 1971 clearing the car’s design. But that was two years after the car went out of production, and not nearly as headline-worthy as Nader’s initial claims.

Part of Nader’s evidence against the Corvair was a promotional film created by Ford Motor Company, in which a Ford test driver purposely turns the Corvair in a way to make it spin around. Such films were not uncommon. GM also had films showing the Ford Econoline pickups standing on their nose under heavy braking.

Engineering

The Chevrolet Corvair engine, unique for an American car, presented a different set of requirements for mechanics, many of whom treated the engine in the same way as they would an engine of normal design, leading to problems.

An engineering weakness not generally highlighted related to fumes and gases entering the passenger area via the heater system, a problem endemic to an air-cooled engine that uses heat radiated from the engine directly to heat air for the passenger compartment. Carbon monoxide and other noxious or deadly gases could enter the sedan passenger areas if exhaust system gaskets aged or failed using this system, since the gaskets were inside the heater box air intakes and air for engine cooling and passenger heating was mixed together as one common airflow. The 1960 model Corvairs used a GM Harrison division gasoline heater located in the front trunk area, as its standard heater, similar to the Eberspächer heater offered as an auxiliary heater by Volkswagen as a dealer-installed option. It operated independently from fuel in the cars' gas tank, but this feature became optional in 1961 and was dropped in 1965 due to weak consumer demand. Chronic oil leakage from the pushrod tubes, caused by GM's poor choice of pushrod tube seal material, also contaminated the passenger heating air. That air might also become noxious if a 6-inch (152 mm) wide rubber seal almost 16 feet (5 m) long, located between the engine assembly and the body, was not maintained in like-new condition. Another common problem in the earlier years was oil leakage caused by dissimilar metal thermal expansion on the aluminum and steel engine. Chevrolet wrestled with several problems of this nature the entire time the Corvair was in production with varying degrees of success.

The interior air would also be contaminated if the voltage regulator allowed an over-voltage condition and the original battery vent hoses were not attached. The battery, which was mounted in the engine compartment, could emit hydrogen if overcharged. Chevrolet installed special battery caps and hoses that vented the battery to air outside the engine compartment, but these were often discarded by owners during the car's life.

The Volkswagen Beetle (Type I), another automobile with an air cooled engine, had a heater system which better isolated fresh air from engine cooling air fumes, and was only susceptible to carbon monoxide contamination from the two heat exchanger to muffler seals at the rear of the engine, as opposed to the eight exhaust joints in the Corvair system. This air contamination problem is illustrated by the fact that many American cities' taxi regulations had prohibited air-cooled engine cars from being used as taxicabs when they derived their heated air from engine exhaust heat, decades before the Corvair and VW Beetle entered the market.

A criticism in Lawyer Ralph Nader's 1965 book concerned the steering column design. Like most cars of its era, the Corvair's steering column was rigid and could impale the driver in a front-end collision. While the Corvair's steering box was mounted ahead of the front cross-member, it was well behind the frame horns, in what would later be called a "crumple zone," and could, in a severe front-end collision, push the steering column and steering wheel toward the driver. In practice, most driver chest injuries were sustained due to the lack of a shoulder belt, rather than steering column intrusion. Any increase in risk of injury due to steering column intrusion in a front-end collision was, however, more than offset by the absence of an incompressible engine and transmission in the front of the vehicle, which commonly intruded into passenger compartments on vehicles of the era. Chevrolet, aware of Nader's criticism, changed the steering shaft to a two-part design with a frangible joint in the 1966 model year, and a collapsible steering column was provided in 1967, towards the end of the model's life span.

In defense of Nader's criticism of the Corvair's swing axle rear suspension, some writers have pointed to a critical factor in the combination of soft "American-style" springs together with an unusually large and heavy engine for a rear-engine, air-cooled car. Both of these factors would have greatly increased the potential for excessive body lean and over-cambering of the suspension in sharp turns, as compared with smaller and lighter contemporary Volkswagens, Renaults, Porsches, and other rear-engined cars. In addition, the car was designed to avoid terminal oversteer by using very low air pressure in the front tires, typically 12 to 15 pounds force per square inch (80 to 100 kPa), so that they would begin to understeer (slip) before the swing axle oversteer would come into play. Although this pressure was quite adequate for the very lightweight Corvair front end, owners and mechanics, either through ignorance of the necessity for this pressure differential between front and rear or thinking that the pressure was too low for the front, would frequently inflate the front tires to more "normal" pressures, thus ensuring that the rear of the car would lose traction before the front, causing it to oversteer. It should be mentioned that the Corvair is by no means unique in requiring dissimilar front and rear tire pressures for normal controllability. The Ford Explorer had widely-publicized stability problems when equal pressures were used. See Firestone vs Ford Motor Company controversy.

Although Nader probably overstated the severity of the handling problems, as was later found by US National Highway Traffic Safety Administration investigators, Chevrolet made changes to the suspension: in 1964, adding a transverse leaf spring extending between the rear wheels to limit rear wheel camber change. In 1965 the Corvair got a state of the art fully independent rear suspension closely resembling that of the contemporary Corvette, even sharing some components. These changes were, however, viewed as Chevrolet's recognition of possible problems with the original design.

Production notes

Year	Production	Spotting	Notes
align=left	First year
1961	337,371	Solid front with small emblem and full-width bar	Monza sedan, Lakewood station wagon, Corvan and Greenbrier vans, and Loadside and Rampside pickups added; 145 in³ engine and optional three-speed manual; spare tire now in the rear
align=left	Turbocharged Monza Spyder added
1963	288,419	Full-width single-slit front with small emblem above	Lakewood station wagon and Loadside pickup discontinued
align=left	Last year of the Rampside pickup; improved rear suspension and larger 164 in³ engine
rowspan=5 align=left	Corsa line added; last year of the Greenbrier; new body style and redesigned independent rear suspension
align=left
align=left
1968	15,399	Fully-collapsible steering column
1969	6,000	Last year
Total	1,835,170

Modifications

Many sports car purists were more interested in the Corvair (particularly the 1965 and later cars) than in more conventional designs, such as the Ford Mustang, despite the latter's power advantage. From the first appearance of the Corvair, a large selection of high-performance equipment and modifications became available for it.

Yenko Stinger

Don Yenko, who had been racing Corvettes, could not compete successfully against the Carroll Shelby Mustangs after they arrived on the scene; he therefore decided to race modified Corvairs, beginning with the 1966 model. As the stock Corvair did not fit into any of the SCCA categories, Yenko had to modify four-carburetor Corsas into "sports cars" by removing the back seat; in the process he would introduce various performance improvements. As the SCCA required 100 cars to be manufactured to homologate the model for production racing, Yenko completed 100 Stingers in one month in 1965. Although all were white, as the SCCA required for American cars at the time, there was a great deal of variety between individual cars; some had exterior modifications including fiberglass engine covers with spoilers, some did not; some received engine upgrades developing 160, 190, 220, or 240 hp (119, 142, 164, or 179 kW). All were equipped by the Chevrolet factory with heavy duty suspension, four speed transmission, quicker steering ratio, positraction differentials (50 with 3.89 gears, and 50 with 3.55 when Chevrolet dropped the 3.89) and dual brake master cylinders (the first application of this by Chevrolet, to become stock equipment the next year). The Stingers competed in Class D Production, which was dominated by the Triumph TR4, which was very quick in racing trim; however in its first race in January 1966, the Stinger was able to come in second by only one second. By the end of the 1966 season, Jerry Thompson had won the Central Division Championship and placed fifth in the 1966 Nationals, Dick Thompson, a highly successful Corvette race driver, had won the Northeast Division Championship, and Jim Spencer had won the Central Division Championship, with Dino Milani taking second place.

The next year, however, Chevrolet dropped the Corsa line, and the Monza line was not initially available stock with the four carburetor engine; the engine was eventually offered as a special performance option, however, along with the 3.89 differential. The Monza instrumentation, however, did not have a tachometer or head temperature gauges, which had to be separately installed. The SCCA, on the other hand, had relaxed its ruling regarding color, and the cars were available in red or blue. It is believed that only fourteen 1967 Stingers were built, but Dana Chevrolet, who distributed Stingers on the US West Coast, ordered an additional three similar cars to be built to Stinger specifications, but with the AIR injection system to meet California emissions laws, with Yenko's permission. A total of 185 Stingers are believed to have been built, the last being YS-9700 built for Goodyear Tire and Rubber Company as a tire test vehicle in 1969 – 1970.

Comedian, television star, and car enthusiast Tim Allen currently owns and races Yenko Stinger #YS-043.

John Fitch Corvair Sprint

Longtime roadracer John Fitch was particularly interested in the Corvair as the basis for a spirited road and track oriented car, due to its handling. The basic Sprint received only minor modifications to the engine, bringing it to 155 hp (116 kW), but upgrades to the shock absorbers and springs, adjustments to the wheel alignment, quicker steering ratio, alloy wheels, metallic brake linings, the obligatory wood-rimmed steering wheel (leather available for an additional $9.95) and other such minor alterations made it extremely competitive with European sports cars costing much more. Body options such as spoilers were available, but the most visually remarkable option was the "Ventop", a fiberglass overlay for the C-pillars and rear of the roof that gave the car a "flying buttress" profile.

Fitch went on to design and build a prototype of the Fitch Phoenix, a Corvair-based two-seat sports car, superficially resembling a smaller version of the Mako Shark based Corvette. With a total weight of 1,950 pounds (885 kg), even with a steel body, and with the Corvair engine modified with Weber carburetors to deliver 175 hp (130 kW), the car delivered spirited performance for $8,760. Unfortunately, the Traffic Safety Act of 1966 placed restrictions on the ability to produce automobiles on a small scale; this was followed by Chevrolet's decision to terminate production of the Corvair, which confirmed the end of Fitch's plan. He still retains the prototype however, and occasionally exhibits it at car shows. The car may be glimpsed briefly in the documentary film Gullwing at Twilight: The Bonneville Ride of John Fitch^*.

V8 Corvairs

The ultimate Corvair modification was replacement of the engine with a V8. As daunting as this might seem, two things made it possible:

The Corvair engine rotated in the opposite direction from most other engines, so that if a V8 was placed in the rear seat area (the added weight of a V8 in the original location of the Corvair engine would be abominable to drive) and coupled to the front of the transmission via a supplied custom made clutch gear and input shaft, this would drive the car in the proper direction with four speeds forward and one reverse.
The switch in 1966 to using standard Chevrolet Saginaw gear sets in the manual transmission could handle the torque of a V8.

A radiator occupies the former trunk, in the front of the vehicle. However, the former engine compartment in the rear now is available as luggage space. A complete kit to adapt a Chevrolet small-block V8 to a Corvair was manufactured by a company named Crown Manufacturing, for $600. The resulting vehicle weighed only 2,750 pounds (1250 kg), compared to 3,700 pounds (1680 kg) for a small block Corvette, and possessed independent rear suspension of almost the same design. Crown's prototype with 350 hp (261 kW) Corvette engine recorded an elapsed time of 12.22 seconds and 105 miles per hour (169 km/h) in the quarter mile (402 m). An advantage of this modification is that the mid-engine design provides optimal handling characteristics for the road, as well as excellent drag strip traction without the need for slick or "cheater slick" tires as seen in front engine cars, let alone modifying the wheelbase as on the FX funny cars of the time. Although a few Corvairs have been modified to accept the Chevrolet big-block engine, the added size of the engine makes the work significantly more difficult, and the result, although a great performer, tends to be unreliable. Yenko Corvair YS99 was one of the 300 or so CORV8 conversions made. It is also possible to install a reverse rotation small block chevy in place of the flat six with many modifications.

External links

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