Chevrolet Corvair

The Chevrolet Corvair was a rear-engined automobile produced by General Motors from 1960 to 1969. The Corvair was offered in a wide range of body styles (such as a four-door sedan, coupé, convertible, station wagon, pickup, and America's first mini-van, the Greenbrier) and featured an air-cooled engine, which was unusual for American cars at the time.

The Corvair remains one of GMs most unusual creations. 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).

The Corvair—like the Ford Falcon, Studebaker Lark, Nash Rambler, and Chrysler 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. The "trunk", on the other hand, was in the front of the vehicle, while the spare tire was stored above the flat engine, saving trunk space.

The entire line (which eventually grew to incorporate sedans, coupes, convertibles, vans, pickups and station wagons) 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). 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)

First production Corvairs (1960-1964) were factory equipped with an ignition lock wherein it was possible to start the car and then remove the key. Doing so in Southern California and being caught at it by the Los Angeles Police Department was a guaranteed ticket to a weekend in jail.

History

The Corvair name originated as a Chevrolet Corvette-based fastback concept car from 1954. Many future Chevrolet models were based on the Corvette, including the Chevrolet Nomad and Chevrolet Impala.

The early 1960 models were rather boxy and had few amenities, but the line quickly grew from plain 4-door sedans with bench seats (the base 500 and slightly more upscale 700) to sportier 2-door coupes with bucket seats, the Monza 900.

1961

For 1961 Chevrolet added an optional 4-speed manual transmission to augment the standard 3-speed manual and optional 2-speed 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, but 84 hp (63 kW) when mated to the optional automatic transmission. The high performance engine was rated at 98 hp (73 kW).

A rear-engine 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 with this particular model, however.

That same year, Chevrolet also added a panel van (the Corvan), a window van (the Greenbrier), and a pickup, which was notable not only for the fact that the air-cooled engine was mounted under the pickup bed, but that the side of the pickup bed folded down to form a ramp, hence its name, the Rampside.

The most notable addition in 1961 was the new "Super De Luxe" Monza trim package available. The Monza package included bucket seats up front and carpet all around in addition to a few extra chrome dress up items. Most commonly it was seen with a 4 speed on the floor shifter and the high performance engine. At the time this package was heralded by some as "the poor man's Porsche" since it was the closest thing to an affordable sports car on the american streets. Though introduced half way through the 61 model year, the Monza Coupe was the best selling model in the line up.

1962 to 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. A convertible option was added as well. The 1963 model year saw the end of the Lakewood stationwagon and the availability of a long 3.08 gear for improved fuel economy, but the Corvair remained largely the same as in 1962.

1964

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.

However, 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.

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 safety commission 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, was 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

File:Corvairs.jpg

Cover of IND 1965 Cars publication, featuring Corvair

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 had an enhanced set of instruments, including a head temperature gauge, as well as a short throw shifter when equipped with the manual transmission. The base Corsa 140 horsepower (104 kW) engine was notable for the fact that the engine used 4 single-throat carburetors, 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 as well.

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, and 1965 would be the last year for the Greenbrier window van.

1966-1969

The 1966 lineup remained essentially unchanged from 1965, and sales began to decline as a result of Nader's book, the popular new Mustang, and rumors of the upcoming Camaro. One change of note was a more robust 4 speed synchromesh transmission for 1966, using the standard Saginaw gearset used by other GM vehicles. The new transmission was capable of handling more stress, though generally wasn't as smooth shifting as the earlier transmisison. A small flexible plastic air dam was installed below the front end.

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.

In 1968 the line was trimmed even further to just the coupe and convertible, and sales were down to 15,400.

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. This model year was equipped with collapsible steering columns, a final response to one of the most valid safety criticisms.

In the 1970s an abortive attempt was made to found a company dedicated to acquiring 1965-1969 Corvairs in good condition and rebuilding them from the ground up. The finished car was not sold as a restoration, but with newer headlights and taillights and minor mechanical improvements, as sort of an update. It is not known how many were completed.

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 (and uniquely dangerous) related to fumes and gases entering the passenger area via the heater system, a problem endemic to an air-cooled engine. Carbon monoxide and other noxious or deadly gases could enter the sedan passenger areas if exhaust system gaskets aged or failed, 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. Chronic oil leakage from the pushrod tubes, which was endemic to the engine, also contaminated the heating air, as did the tendency for earlier engines to blow a head gasket. That air would 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.

The interior air would also be contaminated if the owner did not keep the carefully engineered battery container, located in the engine compartment, intact and in like new condition. The Volkswagen Beetle, another automobile with an air cooled engine, located the battery in the passenger compartment under the rear seat. This may have been a source of noxious interior fumes in that vehicle as well, though perhaps on a lesser scale. VW better isolated fresh air, and used no-joint one-piece exhaust pipes inside their heater intakes to prevent exhaust leaks and ensure clean interior air.

As a matter of fact, this air contamination problem is brilliantly illustrated by the fact that many American cities taxi regulations had probibited air-cooled engine cars from being used as taxicabs decades before the Corvair entered the market.

'Unsafe at any speed'

Another criticism in Nader's book concerned the steering column design. Like most cars of its era, the Corvair's steering column was rigid and could be forced into the driver by a front-end collision. However, in the Corvair, the steering column actually terminated ahead of the front axle. This forward positioning, plus the lack of an engine in front to minimize crumpling, made dangerous rearward displacement of the steering column in a collision unusually likely. A collapsible steering column was eventually 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 absolute 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 spin.

Although Nader probably overstated the severity of the handling problems, Chevrolet themselves made changes to the suspension: in 1964 they added a transverse leaf spring extending between the rear wheels to minimize rear wheel camber change, and in 1965 the Corvair got a state of the art fully independent rear suspension closely resembling that of the contemporary Corvette, and even sharing some components. These changes were, however, viewed as Chevrolet's recognition of possible problems with the original design.

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 Carrol 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 (later to race Corvettes) 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 engines were eventually offered as a special performance option, however, along with the 3.89 differential. The Monza instrumentation, however, did not have a tachometer, oil pressure and temperature gauges, or ammeter; all 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 specs 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, through as late as 1980.

Comedian, television star, and car enthusiast Tim Allen currently owns and races the only known Yenko Stinger convertible.

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 horsepower (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 horsepower (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.

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 fact that 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 the transaxle rotated 180 degrees to meet it, the gearing would drive the car in the proper direction and not four speeds in reverse and one forward; and the switch in 1966 to using standard Chevrolet Saginaw gearsets in the manual transmission, which 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 horsepower (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 rearward weight distribution gives excellent traction without even the need for slick or "cheater slick" tires, let alone modifying the wheelbase as on the FX cars of the time; the mid-engine design also provides optimal handling characteristics. 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.

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