GM J platform

J-body
Overview
Manufacturer	General Motors
Production	1981–2005
Body and chassis
Class	Compact (North America) Mid-size (Global)
Layout	FF layout
Body style(s)	2-door convertible 2-door coupe 2-door notchback sedan 3-door hatchback 4-door sedan 5-door station wagon 5-door hatchback
Chronology
Predecessor	GM H platform (RWD) (North America)
Successor	GM2900 platform (Europe) GM Delta (North America)

The J platform, or J-body, was General Motors' inexpensive front-wheel drive automobile platform from the 1980s and 1990s. The platform replaced the GM H platform. The J-platform is the only platform of GM to have a model in each of its "Original 5" United States passenger car divisions (Buick, Cadillac, Chevrolet, Oldsmobile, and Pontiac). The first J-body cars were the Chevrolet Cavalier, Pontiac J2000, and the Oldsmobile Firenza which entered production on March 23, 1981 as 1982 models.^[1] The Cavalier was phased out at the end of 2004 in favor of the new Chevrolet Cobalt. The last surviving J-body car, the Mexican-built Pontiac Sunfire, ended production in June 2005. There are three generations of the J-body: 1982 to 1987 (or until 1988 or 1989 depending on the model), 1988 to 1994, and 1995 to 2005.

Except for cosmetic differences, engine upgrades and the discontinuation of certain models, the platform remained largely unchanged throughout the years.

Design of the J-body dated back to the mid-1970s. At that time, GM-controlled divisions in different parts of the world manufactured totally different rear-wheel drive C-segment cars - the Chevrolet Vega in America, the Vauxhall Cavalier/Opel Ascona in Europe, the Holden Torana in Australia and the Isuzu Florian in Japan. Due to the exterior dimensions, and engines offered were found to be in compliance with Japanese regulations, the platform was classed in the favorable "compact" designation, and competed with other Japanese made products sold in Japan at the time. Isuzu also supplied kits for Holden's J-car version, the Camira.^[2]

It was decided that a common replacement would be developed to eliminate duplication of engineering effort and ensure parts interchangeability. When the Arab Oil Embargo forced CAFE mandates, and the fear of US$3.00 for a gallon of gasoline, the J-body was practically produced straight off the drawing board.

In continental Europe, the car was sold as the Opel Ascona. In Britain, it was sold as the Vauxhall Cavalier. No matter which badging they carried, European production occurred in plants in Germany, Belgium, and Britain.^[3] It was generally well received but was narrowly beaten to the European Car of the Year accolade by the Renault 9.^[4] At the time, it set new standards for performance and economy in this size of car in Europe; for instance, the 1.6 petrol engined Cavalier for the British market had a top speed of 105 mph, compared to the 101 mph top speed of the 2.0 petrol engined Ford Cortina - its key competitor.^[3]

The fourth character in the Vehicle Identification Number for a J-body car is "J".

Iterations

In all cases, convertibles were not completed at the factory by General Motors; final assembly was subcontracted. In North America, this was done by American Sunroof Corporation (ASC). In Europe, it was done by Baur while convertibles for the German market were assembled by two different coachbuilders: Keinath and Hammond & Thiede. Brazilian convertibles made by Envemo and Sulam.

Approximately 10,150,000 GM J platform cars were sold across eleven marques on six continents from 1982 through 1997, not counting Daewoo Espero sales.^[5][6][7][8] Consequently, it is the fifth best selling automobile platform in automotive history.

References