With all the furor surrounding Ford and Chevrolet’s new 300+ horsepower V6 Mustang and Camaro, you would think hot six-cylinder engines were a new idea, at least in America. Not so — in 1965, about a decade after the demise of the Hudson Hornet and its “Twin H-Power” straight six, Pontiac introduced a sophisticated new overhead cam six-cylinder engine that promised V8 power and six-cylinder economy. This week, we look at the short life of the 1966–1969 Pontiac OHC six, Pontiac Firebird Sprint, and Tempest Le Mans Sprint.
JOHN DELOREAN AT PONTIAC
John Zachary DeLorean was born in Detroit in 1925. Like many automotive executives of his era, he was a second-generation automobile man; his father, an immigrant from Alsace-Lorraine, had worked for a time as a millwright for Ford. As a teenager, DeLorean earned a scholarship to Lawrence Institute of Technology (now Lawrence Technological University) and, after a brief stint as an insurance salesman, took a job with the Chrysler Corporation. In 1952, he joined the Packard Motor Car Company, working with Forest McFarland, Packard’s chief R&D engineer, on projects like the second-generation Ultramatic transmission.
Packard was quite small by the standards of domestic automakers, with a deeply ingrained culture of unhurried Old World craftsmanship. Largely unencumbered by bureaucracy and nurtured by the ever-patient McFarland, DeLorean thrived, enjoying a level of autonomy rare in a conservative industry. When McFarland departed to join Buick in 1956, DeLorean was promoted to replace him as head of R&D.
If the Studebaker-Packard Corporation had been healthier, DeLorean might have enjoyed a fine career there. Unfortunately, by 1956, the company was staggering toward collapse. That summer, the Studebaker-Packard board decided to eliminate Packard’s own design and manufacturing facilities, consolidating development and production at the Studebaker plant in South Bend, Indiana. DeLorean started looking for other job opportunities.
He was soon contacted by Oliver K. Kelley, then the head of GM’s corporate Transmission Development Group (and one of the principal architects of the original Hydra-Matic and Dynaflow transmissions). Kelley made a concerted effort to recruit DeLorean and arranged a series of interviews for him, including a meeting with new Pontiac general manager Semon E. “Bunkie” Knudsen.
Although DeLorean was wary of GM’s top-heavy corporate culture and put off by Pontiac’s stodgy reputation, Knudsen convinced him that they could reinvent Pontiac and offered him a lucrative salary (around $14,000 a year, a handsome sum in the mid-fifties) to become the head of Pontiac’s new advanced engineering section.
DeLorean arrived at Pontiac on September 1, reporting to new chief engineer E.M. (Pete) Estes, whom Knudsen had recently recruited from Oldsmobile. DeLorean’s role was to develop new engineering concepts that might eventually find their way into production Pontiacs. As at Packard, he was given a free hand to explore novel and sometimes radical ideas, ranging from a rear transaxle with an unusual flexible driveshaft (later used for the 1961 Pontiac Tempest) to an experimental six with an unusual combination of air- and water-cooling.
By 1959, DeLorean had embarked on a new project: an advanced six-cylinder engine with a single belt-driven overhead camshaft.
ORIGINS OF THE PONTIAC OHC SIX
In the early sixties, six-cylinder engines were enjoying a modest resurgence in the American market. A decade earlier, buyers had shown a marked preference for the new breed of OHV V-8s, leading some mid-priced automakers to abandon sixes entirely. Pontiac had dropped its venerable flathead six at the end of the 1954 model year and didn’t offer another six-cylinder engine until 1964. The sharp recession that began in 1957 sent the pendulum swinging the other way, leading to a new generation of six-cylinder compacts. Pontiac had bucked that trend with the four-cylinder Tempest, but it was clear that the division would need a new six eventually. That also presented an attractive opportunity to explore new ideas.
Both DeLorean and motor engineer Malcolm McKellar were intrigued with OHC engines both for their practical advantages (see the sidebar above) and for their rather racy connotations. Although overhead camshafts were very rare for American production cars, they were almost de rigueur for European racing engines, and DOHC Offenhauser racing engines had been extremely successful at the Indianapolis 500 for many years.
The direct inspiration for Pontiac’s OHC engines was the contemporary Mercedes big six, a 183 cu. in. (2,996 cc) engine found in the Mercedes 300 sedans and coupes and, in somewhat more highly tuned form, the 300SL sports cars. With its iron block and single overhead camshaft, the Mercedes-Benz engine was not as exotic as the twin-cam engines from Jaguar and Alfa Romeo, but it had an impressive competition pedigree and offered a fair compromise between power, fuel economy, and complexity. It became the conceptual starting point for Pontiac’s design work.