Pity the second-generation Chevrolet Camaro. Born late — a delivery fraught with complications — it was nearly snuffed out in adolescence. Although it survived to a ripe old age, it has never inspired the same nostalgia as its beloved 1967-1969 predecessor, perhaps because it arrived in the fray of one of the most contentious public debates of the 20th century: the battle over automotive emissions and the use of leaded gasoline. This is the story of the 1970-1981 Chevrolet Camaro and the rise and fall of leaded gasoline.
THE SECOND GENERATION CHEVROLET CAMARO
The first-generation Chevrolet Camaro, Chevrolet’s belated response to the Ford Mustang, bowed in the fall of 1966 as a 1967 model. Although it won respect for its performance and muscular appearance, neither the Camaro’s looks nor its muscle were enough to let it seriously challenge the popularity of the Mustang. Dearborn’s “pony car” regularly outsold the Camaro (and its F-body sister, the Pontiac Firebird) by a considerable margin. Before its first model year was over, however, Hank Haga’s Chevrolet Styling Studio 2 was already at work on the second-generation Camaro.
The new Camaro was planned for the 1970 model year, which would ordinarily have put it on sale in the fall of 1969. As it happened, the new car didn’t appear until February 26, 1970, around five months late. There is a popular assumption that the delay was caused by labor issues — GM was at war with the United Auto Workers union (UAW) between 1969 and 1972 and there were several lengthy strikes during this period. The real reason was a serious problem with the dies used to make the new car’s complex rear quarter panels. The panels were splitting or wrinkling in early tests, forcing Fisher Body Die Engineering (the one-time independent coachbuilder that manufactured most of GM’s auto bodies) first to modify, then to completely redesign the dies. That in turn forced GM to keep the 1969 Camaro in production for an extra four months. Chevrolet had to scramble to draft expensive and complicated short-term agreements with suppliers, who already stopped producing parts for the outgoing car. All told, the delays cost GM millions of dollars, beyond the already high costs of introducing a new model.
When the second-generation Chevrolet Camaro finally did appear, it made a tremendous splash. It was one of the most radical-looking new designs the industry had seen since the excesses of 1959.
Unlike the Mustang, whose successive revamps from 1964 to 1973 represented a steady evolution of the original concept, the new Camaro was an almost complete stylistic break with its predecessor. The first Camaro, as we have previously seen, evolved from the “Super Nova” concept car of the early sixties. It essentially married the stylistic philosophy of the second-generation Chevrolet Corvair (1965-1969) with the short-deck, long-hood proportions popularized by the Mustang; park a 1967 Chevrolet Camaro next to a post-1965 Corvair and the family resemblance of their basic body shapes is readily apparent. The new Camaro looked more like something from Italy than Detroit. It featured a curvaceous nose and gaping grille that recalled early-sixties Ferrari or Maserati GT cars, particularly on Rally Sport models, which had no bumper ahead of their grille openings.
Under the skin, the new F-body was much more familiar. It was about two inches (51 mm) longer and slightly wider and lower than the 1969 Camaro, but it was structurally very similar. It shared the first-generation car’s semi-monocoque construction, with a separate front subframe carrying the engine and front suspension. Suspension design was substantially the same as before, as were most of the powertrain choices. Front disc brakes were newly standard, but the four-wheel discs that had been available on a very limited basis in 1969 were gone. The new Camaro was almost 200 pounds (90 kg) heavier, thanks to the addition of new side-guard door beams, as well as the more complex inner body stampings necessary for its curvy shape.
The high-performance Z/28 option package returned for 1970, but Chevrolet abandoned the earlier Z/28’s high-strung 302 cu. in. (4,942 cc) engine in favor of the new 350 cu. in. (5,733 cc) LT-1. The LT-1, shared with the Corvette, was rated at 360 gross horsepower (268 kW), about as a strong as the underrated 302, but far more tractable. It could now be ordered with automatic transmission, whereas first-gen Z/28s required a four-speed manual. A big-block V8 remained optional on other Camaros. Chevrolet still called the big Turbojet V8 a “396,” but it was now actually 402 cubic inches (6,587 cc), rated at 350 gross horsepower (261 kW). Chevy briefly announced that the Camaro would offer the big 454 cu. in. (7,443 cc) LS-6 engine offered in the 1970 Chevelle SS, rated at a whopping 450 gross horsepower (336 kW), but it never actually went into production.
The 1970 Chevrolet Camaro was just about as fast as its predecessor despite its extra weight. In May 1970, Car and Driver put its well-prepared automatic Z/28 across the quarter-mile line (402 meters) in the low 14-second range with a trap speed of slightly over 100 mph (161 km/h); Motorcade‘s Dave Epperson managed similar figures. That was excellent performance, but the bottom was about to fall out.
GETTING THE LEAD OUT
About nine months after the Camaro’s belated debut, the U.S. Congress unanimously passed the Clean Air Act of 1970. The Clean Air Act empower the recently created Environmental Protection Agency (EPA) to set and enforce standards for air pollution. The federal government had begun setting limits on automotive emissions for the 1968 model year, two years after the state of California initiated its own, more-stringent standards. The Clean Air Act called for a 90% reduction in automotive emissions by 1975. It also reopened a very old can of worms: the use of lead in gasoline.
To understand the history of leaded gasoline, we must examine some of the basic engineering concepts involved.
One of the most effective ways to improve both an engine’s specific output (its power per unit of displacement) and its specific fuel consumption (fuel burned per unit of power produced) is to increase its compression ratio. A four-stroke engine, like that used in most automobiles, compresses its air-fuel mixture before burning it. This compression has two effects. First, it increases the density of the mixture, packing oxygen and fuel molecules more tightly together, allowing more complete combustion. Second, it increases the energy of that mixture through adiabatic heating, allowing more energy to be extracted from it when it burns. A high static compression ratio (the ratio of the swept volume of each cylinder and combustion chamber when the piston is at bottom dead center — its lowest point — to the combustion chamber volume when the piston is at top dead center — its highest point) gives more power. Because it promotes efficient burning, a high compression ratio also improves fuel economy. For those reasons, the auto industry — spearheaded by General Motors — has long been enthusiastic about high-compression engines, like the high-revving LT-1.
One problem with raising an engine’s compression ratio is that it increases the risk of autoignition, also called detonation, knocking, or pinking. In a spark-fired engine, autoignition is uncontrolled detonation of the fuel mixture before or after the spark plugs fire, usually caused by hot spots in the combustion chamber. Autoignition can be extremely harmful to an engine — at its most severe, it can blow a hole in a piston. The extra adiabatic heating caused by higher compression makes autoignition more likely, which limits how much compression ratios can be safely raised.
GM first became interested in higher compression ratios in the wake of World War 1. At the time, many experts feared that U.S. oil reserves would not be enough to keep up with the expected growth of oil use. They projected shortages by the late 1940s that would force the U.S. to buy much of its oil overseas. To guard against this possibility, GM explored various means of improving engine efficiency. High-compression engines were particularly attractive because they increased both fuel efficiency and power, but detonation remained a daunting obstacle.
PUTTING THE LEAD IN LEADFOOT
Charles Kettering, who became head of GM’s research division in 1919, suggested an alternative. Kettering was aware that certain fuels were more resistant to detonation than others, and he had already worked with the U.S. Army and Bureau of Mines on the prospect of creating anti-knock fuels that would allow existing engine designs to use higher compression ratios.
Kettering’s staff developed a scale for measuring the knock resistance of a fuel, based on the properties of two of the hydrocarbons commonly found in gasoline. Heptane (n-Heptane) had poor knock resistance, so pure heptane was set as the zero point of the scale. Iso-octane (2,2,4-Trimethylpentane) had good knock resistance, so it was given a value of 100. The knock resistance of any given fuel was measured in terms of its octane rating (or octane number), determined by comparing its knock resistance to a mixture of pure heptane and pure iso-octane. If a fuel had the same knock resistance as a blend of 90% iso-octane and 10% heptane, for example, it was assigned an octane number of 90. (This doesn’t mean that the fuel actually contained those percentages of those specific hydrocarbons, just that it has the same resistance to autoignition as such a blend. Also, since some substances have knock resistance higher than iso-octane or lower than heptane, it’s entirely possible to have an octane rating lower than 0 or higher than 100.) Kettering’s challenge was to find a practical, affordable way to raise that octane number.
GM’s interest in boosting the octane of gasoline was by no means a purely sporting one. In the 1920s, the oil company E. I. Du Pont de Nemours owned 35.8% of GM’s stock, and the two companies shared board members. If Kettering could find an economical fuel additive, it could be exceedingly profitable for both GM and DuPont.
With that in mind, it becomes more apparent why Kettering’s superiors rejected one of the most obvious octane boosters: ethyl alcohol. Ethanol has an octane rating of 129 RON (about 116 pump octane), which is substantially better than iso-octane. Although ethanol has significantly less thermal energy than gasoline, a high-compression engine running an 80/20 blend of gasoline and ethanol will still be more efficient than a lower-compression engine burning pure gasoline. Furthermore, since ethyl alcohol is produced by fermenting sugar, it is a renewable resource. Even in the 1920s, scientists were justifiably concerned about the dangers of diverting food crops to produce fuel, but Kettering saw great promise in work being done on converting cellulose into fermentable sugars, allowing ethanol to be produced from waste products like corn husks.
The problem, as far as GM and DuPont were concerned, was that GM could hardly patent ethanol, which greatly limited their profit potential. Moreover, during the era of Prohibition, storing or transporting large quantities of alcohol involved some uncomfortable legal gray areas. Kettering’s superiors ordered him to concentrate on finding a “low-percentage” additive, something that could be added in small amounts to gasoline to boost its octane number — and something that GM could patent and control.
After a lot of surprisingly unscientific trial and error, Kettering and his assistant discovered that a formulation of tetraethyl lead (TEL) greatly improved knock resistance when added to gasoline. TEL was easier to transport and easier to store than alcohol, which absorbs water (to say nothing of the potential hijacking and pilfering encouraged by Prohibition and the Volstead Act). Better yet, TEL’s use as a motor fuel additive could be patented.
General Motors began selling tetraethyl lead as a fuel additive in early 1923. In 1924, GM formed a consortium with Standard Oil (the predecessor of the modern Exxon-Mobil Corporation) called the Ethyl Corporation, which sold high-octane leaded gasoline under the trade name “Ethyl.”
THE LEADED GASOLINE CONTROVERSY
The problem with TEL is that lead is very poisonous, a potent neurotoxin. Members of Kettering’s own staff suffered from lead poisoning and 17 workers at the new TEL production facilities died of lead poisoning between 1923 and 1925. The result was a public outcry that led to a temporary halt of Ethyl production and an investigation by the Public Health Service. The PHS report, issued in late 1925, concluded that there were insufficient grounds to ban the use of tetraethyl lead in gasoline, although the report acknowledged that its conclusions were based on limited data and recommended further study.
Despite that mild warning, the Surgeon General approved the resumption of leaded gasoline production in January 1926. The PHS report was heavily criticized by other public health advocates, including Dr. Yandell Henderson of Yale University and Alice Hamilton of the Harvard Medical School. The impartiality of the Surgeon General’s decision was called into question by the fact the Secretary of the Treasury, under whose auspices both the Surgeon General’s office and the Public Health Service operated in those days, was Andrew Mellon, who personally owned a controlling interest in Gulf Oil, which had recently signed an exclusive contract with the Ethyl Corporation to distribute leaded gasoline in the southeastern U.S.
Ethyl was soon added to more than 90% of American gasoline. Its safety was taken for granted to the extent that in 1936, the Federal Trade Commission issued an order prohibiting Ethyl’s competitors from criticizing or challenging Ethyl’s product as dangerous or unhealthy.
Meanwhile, the amount of lead used in gasoline continued to increase. At the end of the war, the auto industry — again led by GM — pushed the petroleum industry to offer even higher-octane gasoline for civilian use, allowing the development of a new generation of powerful V8 engines. As a result, by the late 1950s, the TEL content of premium gasoline reached as much as 4.25 grams per gallon (0.89 grams/liter).
By the 1950s, some scientists had begun to link the deleterious effects of high levels of lead contamination, both from the used of leaded paint and the widespread use of leaded gasoline, to a sobering array of health problems, particularly among children, including low IQ, mental retardation, and learning disabilities. By the early 1970s, some U.S. public health officials characterized it a public menace.
Automakers and oil companies strenuously denied any causative relationship between leaded gasoline and such health problems. Nonetheless, in 1962, GM and Standard Oil divested themselves of the Ethyl Corporation, arranging its leveraged buyout by Albemarle Paper. Their patent on TEL had expired in 1947, which had curtailed Ethyl’s margins somewhat, but reporter Jamie Kitman, who wrote extensively on the history of leaded gasoline for The Nation in 2000, speculated that the corporation’s one-time parents may have wanted to distance themselves from a potentially disastrous product liability issue.
REMOVING LEAD FROM GASOLINE
By the late 1960s, there was a renewed movement to eliminate the use of lead in gasoline. In 1969, U.S. Secretary of Health, Education, and Welfare (HEW) Robert Finch proposed that the major oil companies begin phasing out leaded gasoline, starting in the summer of 1971. To the shock of nearly everyone in the industry, GM president Ed Cole made a similar proposal at a Society of Automotive Engineers talk in January 1970. In March, Cole announced that GM would reduce the compression ratios of its engines to make them compatible with lead-free regular gasoline starting with the 1971 model year.
Around the same time, Henry Ford II, chairman of Ford Motor Company, sent a letter to 19 major petroleum companies asking them to begin offering lead-free fuels. Leaded gasoline, whose use had, even five years earlier, been taken completely for granted, was suddenly on its way out.
Inevitably, automakers continued to deny any connection between their requests for lead-free gasoline and the health concerns about TEL, insisting that there was no substantive evidence that the small amounts of lead in gasoline represented a hazard. Instead, they maintained that the phase-out was a precursor to the adoption of catalytic converters to meet upcoming California and federal emissions standards. Leaded gasoline was incompatible with catalytic converters, destroying the effectiveness of their active components by fouling them with lead deposits.
Meanwhile, the petroleum industry (including the Ethyl Corporation itself) began a massive PR campaign to protest that “unleaded” gasoline was neither necessary nor cost-effective. Ethyl executives found no support from General Motors, which kept its promise of lowered compression ratios. For the 1971 model year, even the high-winding Chevy LT-1’s compression dropped from 11.0:1 to 9.0:1.
The effect of the reduction on performance was immediately apparent. Chevrolet claimed the reduced compression ratio cost the LT-1 only about 15 net horsepower, but testers were skeptical. Car and Driver‘s May 1971 test of a 1971 Chevrolet Camaro Z/28 found that its quarter-mile trap speed — an excellent measure of a car’s power-to-weight ratio — had dropped by nearly 7 mph (11 km/h) even though their test car was almost 100 pounds (45 kg) lighter than their 1970 tester; such a drop suggesting an actual loss of more than 40 horsepower (30 kW).
The trend would only get worse; for 1972, the LT-1 dropped to 255 net horsepower (190 kW). In April 1972, the best quarter-mile time Road & Track‘s automatic Z/28 could manage was the mid-15-second range, with trap speeds of about 90 mph (145 km/h). For 1973, the LT-1 engine was replaced by the L-82, with milder camshaft with hydraulic, rather than mechanical lifters. Rated 245 net horsepower (183 kW), the L-82 was now the Camaro’s most powerful engine — the 402 had been dropped after the previous season. It also had to move a heavier car; new 5 mph (8 km/h) bumper standards further inflated the F-body’s already substantial curb weight.
Editorials in the automotive press generally condemned the transition to low-lead and lead-free gasoline. (The simple fact that such fuels became universally known as “unleaded,” rather than “lead-free” — implying that lead was a natural component that was being removed, like caffeine from coffee — speaks volumes.) Few of the contemporary car magazines seriously examined the public health issues associated with lead contamination; many were already deeply critical of pollution-control measures and were hardly sympathetic to the catalytic converter argument. All the automotive journalists saw was that their beloved Supercars were being systematically emasculated by politicians with no engineering knowledge or love of cars.
Overweight, increasingly underpowered, and hit with soaring insurance premiums, the unfortunate second-gen Camaro was further impacted by the ongoing conflict between GM and the UAW. A lengthy work stoppage at the Camaro plant in Norwood, Ohio, crippled production for the 1972 model year, reducing total output by almost 40,000 units. The cost of that loss was compounded when more than a thousand completed cars had to be scrapped after their delayed production made them too late to be sold as 1972 models; they did not meet the emissions or safety standards for the 1973 model year.
In the face of these problems, GM looked at the shrinking sales of the entire sporty car market and seriously considered dropping both the Camaro and its Firebird sibling. GM executives were hardly the only ones considering cutting their losses; AMC and Chrysler would drop their pony cars after 1974, while Ford reinvented the Mustang as the Pinto-based Mustang II. Nevertheless, GM finally decided to spare the Camaro the ax, apparently spurred by a grassroots campaign both inside and outside the company.
The F-body was mildly restyled for 1974, neatly incorporating the required new front and rear crash bumpers. Sales began to pick up nicely. Even though performance continued to erode, the Camaro and Firebird remained popular and profitable enough to last through 1981.
The battle over lead, however, was far from over. In 1972, when the EPA announced its intention to regulate the lead content of gasoline, the Ethyl Corporation promptly sued the agency. When regulations calling for a progressive phase-out of TEL were issued in 1973, Ethyl sued again. Their claims were rejected by a U.S. District Court of Appeals in 1976; the U.S. Supreme Court declined to hear the case. The Reagan administration attempt to roll back the lead phase-out in 1981, but political pressure forced them to relent the following year. Facing the loss of their U.S. business, Ethyl and its rivals began aggressively promoting TEL abroad.
Leaded gasoline for automotive use had been all but eliminated in the United States by 1986. Its use in street cars was formally banned at the end of 1995. The European Union finally banned leaded gasoline for passenger-car use in 2000, but leaded petrol remains in common use in many nations around the world, particularly in Africa and the Middle East. Non-passenger-car use of leaded gasoline has been slower to fade. Leaded racing fuel remained in general use until NASCAR finally adopted unleaded gas in early 2007. Aviation gasoline, meanwhile, continues to use TEL, although the most common avgas is now 100 octane “low-lead” fuel with about 2 grams of lead per U.S. gallon, much less than the 130-octane “highly leaded” gasoline previously used. Environmental groups are pressuring the EPA to mandate the removal of lead from aviation gasoline, but as of this writing, no phase-out has yet been announced.
Although the health effects of lead in gasoline have abated noticeably, they may never disappear completely. More than 7 million tons of lead were burned in America between 1923 and 1986. Lead doesn’t break down or decay and it’s so pervasive that it will never be entirely gone. Still, there have been significant reductions in average blood-lead levels since the phase-out. The EPA estimates that the average level of lead in the blood of Americans dropped 78% between 1978 and 1986. A 2007 Amherst College study links the reduced lead levels to concurrent decreases in the incidence of violent crime.
The adoption of unleaded fuels cost petroleum refiners billions of dollars. They dutifully passed those costs along to customers by adding to the price of each gallon of fuel sold. It took several years for unleaded premium fuels to be generally available and the price charged for high-octane unleaded is greater than for comparable leaded premium. Furthermore, some of the additives adopted as alternative octane boosters, such as MTBE, have proven to be toxic in their own right.
One of the concerns raised about the switch to lead-free gasoline was that lead deposits served to lubricate engine valves, saving manufacturers the cost of hardened valve seats. Real-world experience has shown that excessive valve seat wear is only an issue in highly stressed, high-performance engines and the amount of lead necessary to prevent wear is much lower than the amount typically founded in even “low-lead” gasoline. Furthermore, that potential problem is balanced by reduced wear in other areas. Leaded gasoline — and the binding chemicals, such as ethylene dibromide (EDB) added to keep lead deposits from building up on engine components — promotes spark plug fouling, cylinder bore wear, piston ring degradation, and corrosion of the exhaust system. EDB is also a carcinogen, and has been linked to the degradation of the ozone layer.
What about the poor, beleaguered second-generation Camaro? Ironically, its popularity at the time has done no favors for its reputation today. Although the Camaro was never very common outside the U.S., if you’re an American of a certain age, the chances are that you owned one, or knew someone who did. Sheer ubiquity soon dulled the impact of styling that seemed so fresh and daring in the spring of 1970. By the time its replacement bowed in the fall of 1981, many people were more than ready to forget it and the era of inflation, gas rationing, and controversy in which it appeared.
The early (1970-1972) cars have their fans, to be sure, but they have never been as desirable as the first-generation Camaro, and probably never will be. It’s a shame — had the Camaro appeared before the smog and safety controversies, it would probably be considered a classic like its predecessor.
Sometimes, history has no mercy for those born in the wrong place at the wrong time.
NOTES ON SOURCES
Our sources for the history of leaded gasoline included Jamie Kitman’s lengthy essay “The Secret History of Lead,” The Nation 20 March 2000 issue of The Nation, www.thenation. com/ doc/20000320/kitman/single, accessed 30 May 2008; papers by William Kovarik, Ph.D., reprinted on his website: “Leaded gasoline: history and current situation,” n.d., www.radford. edu/~wkovarik/ethylwar/, accessed 30 May 2008; “Ethyl: The 1920s Environmental Conflict Over Leaded Gasoline and Alternative Fuels,” 26 March 2003, www.radford. edu/~wkovarik/papers/ethylconflict.html, accessed 30 May 2008; “Henry Ford, Charles Kettering, and the ‘Fuel of the Future,'” Automotive History Review #32 (Spring 1998), pp. 7-27, www.radford. edu/~wkovarik/papers/fuel.html, accessed 30 May 2008; “Charles F. Kettering and the 1921 Discovery of Tetraethyl Lead In the Context of Technological Alternatives,” originally presented to the Society of American Engineers Fuels & Lubricants Conference, Baltimore, MD, 1994, revised 1999, www.radford. edu/~wkovarik/papers/fuel.html, accessed 30 May 2008; Jessica Wolpaw Reyes, “Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime,” National Bureau of Economic Research (NBER) Working Paper No. 13097, www.nber. org/papers/w13097, issued May 2007, accessed 1 June 2008; and Maurice Hendry, “Hillbilly Genius: ‘The Great Boss Ket,'” Special Interest Autos #51 (June 1979), pp. 20-27. We also consulted John Ethridge, “Gettin’ the Lead Out,” Motor Trend Vol. 22, No. 5 (May 1970), pp. 48-50, as a representative example of the automotive press’s reaction to the removal of lead from gasoline.
Sources on the 1970½-1981 Chevrolet Camaro included the Camaro Research Group website, “Primary Research and Restoration Data for First-Generation Camaros,” ed. Rich Fields, 1998-2008, www.camaros. org/index.shtml, accessed 30 May 2008; Mike Maciolak, Camaro Model Info, 2006, www.nastyz28. com/ index.php?page=camarofacts, accessed 30 May 2008; and the following vintage road tests: Ron Wakefield, “1970 Camaro & Firebird: Chevrolet & Pontiac versions of a new American GT, plus a facelifted Corvette for 1970,” Road & Track March 1970, reprinted in Firebird and Trans-Am Muscle Portfolio 1967-1972, ed. R.M. Clarke (Cobham, Surrey: Brooklands Books Ltd., 1998); “Chevrolet Camaro: The Z/28 version would be every bit as much at home on the narrow, twisting streets of Monte Carlo as it is on Interstate 80,” Car and Driver May 1970; “1970 Chevrolet Camaro,” Road & Track May 1970; Dave Epperson, “Zapped by a Z28 Camaro,” Motorcade May 1970; “New and Improved: The Camaro SS approaches GT status,” Road Test August 1970; “Chevrolet Camaro Z28: Underneath last year’s smooth exterior beats 1971’s low-compression engine,” Car and Driver May 1971; and “Camaros for Everything: An engineered guide through a thicket of options for luxury, performance or combinations thereof,” Road & Track April 1972, all of which are reprinted in Camaro Muscle Portfolio 1967-1973, ed. R.M. Clarke (Cobham, Surrey: Brooklands Books Ltd., 1992).