Isuzu Gemini  I-Mark

 1974 First generation

Also called	Isuzu Bellett Gemini Isuzu I-Mark Opel-Isuzu Buick Opel
Production	1974–1984
Class	Subcompact
Body style	2-door coupé 4-door sedan
Layout	FR layout
Platform	T-body
Engine	1,584 cc G161Z I4 1,817 cc G180Z I4 1,817 cc G180W DOHC I4 1,817 cc 4FB1 diesel I4 1,817 cc 4FB1T TD I4
Related	Isuzu Piazza Daewoo Maepsy Holden Gemini Opel Kadett Pontiac Acadian Pontiac T1000 Vauxhall Chevette

The first Gemini was the Bellett Gemini, first seen in November 1974. It was based on the third-generation Opel Kadett C on the General Motors T-car platform and came in four-door sedan and two-door coupe body styles. The chassis code was PF50, although the later 1.8-liter versions were called PF60 and the diesels PFD60.

In June 1979,the Gemini received a new slant nose with rectangular headlights and a redesigned rear end. The changes were actually more comprehensive than that, also including a redesigned (longer) engine bay and a wider radiator opening for two new engines added in November (the twin cam G180W and the new 4FB1 diesel) which both required wider radiators for more air for cooling.

In Japan, sports models were available under the names ZZ/R, ZZ/T and ZZ/E. These were equipped with an Isuzu G180W 8-valve DOHC 1.8-liter engine, most commonly fuel-injected, producing 97 kW at the flywheel. These models also came with a shortened remote throw manual shift lever and optional factory LSD differential. A version of the diesel with electronic fuel injection was also added; this provided 8% more power than the regular version (66 versus 61 PS). For those who wanted more, there was also the 73 PS (54 kW) turbo diesel, which also received a standard rear anti-roll bar. Counterintuitively, the two more powerful diesels were not available with the coupé bodywork.

The Gemini was complemented in 1981 by the Giugiaro-designed coupé Isuzu Piazza, based on the Gemini's platform, which was introduced in the United States in 1983 as the Isuzu Impulse and in Australia in 1986 as the Holden Piazza.

In other markets

The North American market version was originally sold as the "Opel by Isuzu" and then the Buick Opel, but for the 1981 model year it metamorphosed into the "Isuzu I-Mark". The diesel engine was available in the I-mark, but the standard engine was a 78 hp (58 kW) (SAE net) version of the 1.8 litre G181Z engine.The diesel gradually lost sales after USA's love affair with the diesel car came to an end in the early eighties, and eventually it was only available in a single coupé version.

Isuzu Gemini was also sold in South Korea as Saehan Gemini, whose manufacturer became Daewoo Motors in 1982. It then became Daewoo Maepsy after 1982 and remained on sale (later as the Maepsy-Na after a facelift) until it was replaced by Daewoo LeMans in 1986.

In addition to sedan and coupé models, Holden in Australia produced the Gemini as a three-door station wagon and three-door panel van, which were derived from the Opel Kadett C Caravan and Vauxhall Chevette wagon, with Isuzu Gemini front panels. The panel van's side panels came from the Bedford Chevanne. The Australian Holden Gemini was fitted with an Isuzu G161Z petrol engine, although 1979 and later models were available with a 1.8-litre 8-valve SOHC diesel engine (4FB1). The more common G161Z was a 1.6-liter 8-valve SOHC fed by a Nikki carburettor. The Holden Gemini was Wheels magazine's Car of the Year for 1975.

In Europe, the 1976 Gemini was equipped with a 1.3-liter engine known as the G131C, which was adopted by Opel in Germany for their Opel Kadett.

Sold as:

• 1975–1984 - Holden Gemini - Australia (1982–1984 in New Zealand badged as an Isuzu, as the brand had been established by the Bellett)
• 1975–1983 - Opel Gemini - Malaysia, Thailand
• 1976–1979 - Opel Isuzu/Buick Opel - United States
• 1976–1982 - Saehan Gemini - South Korea ("Saehan Bird" in the export)
• 1983–1986 - Daewoo Maepsy/Maepsy-Na - South Korea, Saehan Maepsy before
• 1982–1988 - Saehan/Daewoo Max - pickup version, South Korea
• 1981–1984 - Isuzu I-Mark

General Motors sought a replacement for their world car T-body Kadett / Gemini, and this time, instead of building one design on several continents, they decided to build a world car in one location and export it to several continents. As a considerable portion of the T-body manufacturing had been turned over to Isuzu in Japan for economic reasons, so would the manufacturing of the replacement. In 1984, Isuzu again commissioned Giorgetto Giugiaro who was responsible for the 117 Coupé and the Piazza. This time, he was to design an economy car on the new front-wheel drive R-body platform. The R-body featured a MacPherson strut front suspension and beam axle rear suspension, which foreshadowed most of GM's offerings through their current model lineup. Giugiaro's design followed the Piazza design very closely in shape and detail, though the proportions made the Gemini appear shorter and taller in its three-door version, and a four-door sedan (notch back) was also designed.

Unfortunately for everyone involved, Isuzu presented the designs to GM prior to freezing them, and GM ordered a number of detail changes to them without ever consulting the designer, Giugiaro, which was taken as an insult, and ended the long relationship between the noted Italian designer and Japan's oldest car builder. The insult was serious enough to Giugiaro that he denied the design was his until a decade after the vehicle went out of production.

The R-body Gemini was introduced in May 1985 as the 'Gemini FF, with an all-new line of engines. In Japan, originally with chassis code JT150, it was available with a carburetted 1.5-liter SOHC engine. An also newly developed 1.5-liter inline four diesel engine (JT600) was added to the lineup in November. At the other end of the lineup, a 120 PS (88 kW) fuel-injected and turbocharged version of the 1.5-liter 4XB1 engine ("Irmscher") was added in May 1986. Originally, the transmission started out with a choice of a 5-speed manual or a 3-speed automatic, but NAVi5, an automated manual transmission, was added in 1986.

The FF Gemini underwent a facelift in February 1987, receiving a more aggressive front styling with wraparound headlight as well as other minor changes. At the same time the "FF" moniker was dropped, as parallel production of the preceding RWD Gemini came to an end. In March 1987 the Gemini saw its European premier, at the Geneva Salon. European sales of the already somewhat dated Gemini were disappointing, and Isuzu soon withdrew from the European passenger car market entirely.

A 1.6-liter DOHC engine with 135 PS (99 kW) was introduced in February 1988. Export versions were also available with a smaller 1.3-liter four to suit taxation systems based on displacement.This offered 72 PS (53 kW), while export specification 1.5s had 76 PS (56 kW) on tap and the naturally aspirated diesel offered 52 PS (38 kW) outside of Japan. Trim levels were widely varied, from basic models ("C/C" in Japan, "LT" in general export markets, and "S" in the US) to Irmscher, ZZ, and Lotus Tuned versions, and plenty of optional equipment and dealer options were available.

 North America

In the US, the vehicle was available from Chevrolet (and later Geo) as the Spectrum, or from Isuzu themselves, as the I-Mark. GM's Pontiac division sold the I-Mark as the Pontiac Sunburst in Canada from 1985 to 1988. GM Canada announced that the Sunburst's replacement would be the Passport Optima in 1989. For GM, this was an entry level vehicle to attract young buyers and to compete with Japanese midsize cars in the US market. Chevrolet's Spectrum lacked many of the options and equipment of the I-Mark, though both were available with the 70 hp (52 kW) 1.5-liter SOHC non-turbo and 110 hp (82 kW) turbo engines, but no diesel engines were offered in the US. The turbo model I-Mark was called the RS model in 1988 and then changed to the LS model in 1989. The I-Mark was available with the 125 hp (93 kW) 1.6-liter DOHC engine in 1989 only, as the RS model. In 1988 and 1989, the LS and RS models were offered with Lotus Tuned Suspension, the sportier suspension featuring more rigid dampers, alternate spring rates, and bigger sway bars.

Sold as:

• 1985–1989 Isuzu I-Mark - United States, Canada
• 1985–1990 Isuzu Gemini - Japan, Europe, and Central America
• 1985–1988 Chevrolet Spectrum - United States & Canada
• 1989 Geo Spectrum - United States
• 1985–1989 Pontiac Sunburst - Canada
• 1985–1990 Holden Gemini - Australia and New Zealand
• 1985–1990 Chevrolet Gemini - Chile