Petrol / gasoline

Opel had introduced a new generation of petrol/gasoline engines in 1966 with the Rekord B and these were the engines that reappeared in the Rekord D. As before, the stroke length was fixed at 69.8 mm: differences in engine size were achieved by varying the cylinder bore. The engine featured an unusual Camshaft in Head (CIH) configuration. The chain-driven camshaft was positioned directly above the cylinders but this was not a conventional ohc design. The camshaft operated the valves using rocker arms because the camshaft itself was positioned too low above the cylinders to permit direct action from the camshaft on the valves ends. One reason for this may have been cosmetic. Opel's so-called "CIH" engine configuration allowed the Rekord to incorporate the low bonnet/hood lines that style-conscious product development departments called for.

Although the Rekord D shared its wheelbase with its predecessor, in other respects it respected the tendency of Opel Rekords to move slightly upmarket with each new model. The Rekord D was heavier than the Rekord C and the previous model's 1492 cc engine was no longer offered. The smallest power unit at launch, and the one that would be the top seller with this model, was a 1698 cc engine with the low 8.2:1 compression ratio and 66 PS (49 kW) as on the predecessor. The 1698 cc unit was also offered with a twin barrel carburetter and a compression ratio of 9.8:1, offering a maximum power output of 83 PS (61 kW) and much improved torque. Drivers of this "1700 S" engined Rekord had to pay for higher octane fuel, however, and there was also a price to be paid in terms of reduced fuel economy.

Customers wanting more performance from their Rekord could specify the "1900 S" engine of 1897 cc, providing a maximum power output of 97 PS (71 kW) supported by a 9.8:1 compression ratio and a twin chamber carburetter. Like the high compression "1700 S" unit, the "1900 S" needed high octane fuel, but it did provide a top speed of 165 km/h, making it good for more than 100 mph in non-metric export markets. This was the fastest Opel Rekord D on launch, there being no longer any six-cylinder engined Rekords. Anyone wishing to buy a Rekord bodied car with a six-cylinder engine would need to pay also for the enhanced specification of the six-cylinder Opel Commodore with which the Rekord again shared its body.

Early on in the Rekord D's production, Opel also released SAE power figures alongside the DIN norm, with the 1900 S engine producing a claimed 105 PS (77 kW) at 5200 rpm and 17.1 kg⋅m (168 N⋅m; 124 lb⋅ft) at 3800 rpm under SAE standards. This was the only engine offered by Opel's Japanese importer.^[2]

In 1975, the Petrol/gasoline lead law came into force, more than halving the amount of lead that could be added to petrol in West Germany. Similar legislation came into effect in key export markets across western Europe. For the oil companies the addition of lead to fuel provided a simple and inexpensive way to vary octane levels. Having lobbied vigorously against the legislative restrictions, they now responded by reducing fuel octane ratings on the forecourts. The 98 octane fuel on which the Rekord's high compression engines depended was reduced in the super grade fuel normally available, while low lead 98 octane fuel became hard to find and very expensive. For the entry level Opel Rekord "1700 N" claimed maximum power was reduced, in 1975, by 6 PS to 60 PS (44 kW). The high compression "1700 S" version was withdrawn, and the range was extended by a low compression version of the 1897 cc unit, sometimes known as the "1900 N" and providing a maximum power of 75 PS (55 kW) and a compression ratio of just 7.6:1. The "1900 S" high compression ratio version of this engine had its maximum power reduced from 97 to 90 PS (71 to 66 kW) reflecting a compression ratio reduced from 9.8:1 to 8.8:1, which enabled it to use the new reduced octane "super" grade fuels without knocking. In some markets, such as Sweden and Switzerland, emissions controls were even stricter and the new engine produced only 88 PS (65 kW), while the 1700 engine was discontinued there.^[3]

To compensate for the loss of performance on the "1900 S" Opel now increased the cylinder bores further and introduced, in September 1975, a 1979 cc version of the engine for their Rekord "2000 S". 100 PS (74 kW) of maximum power was claimed for what was the fastest Rekord from this generation. Neither its power nor its performance matched the "1900 H" version of the old 106 hp Opel Rekord C however, which presumably reflected changed priorities in the market place following the fuel shortages and price shocks of the mid 1970s.

Diesel

September 1972 saw the introduction of the first diesel powered Opel Rekord, with which the manufacturer launched a determined assault on the lucrative stranglehold that Mercedes-Benz enjoyed over the taxi market in West Germany and, to varying extents, in many of the export markets where the firms competed. The four cylinder 2068 cc diesel unit was not based on the Rekord's "CIH" gasoline/petrol engines, but was a newer design. The "Caravan" wagon was originally not available with the diesel engine, but a five-door diesel estate was added to the lineup at the 1973 Frankfurt Motor Show (September).^[4]

The fuel feed system employed a Bosch diesel injection pump. The unit's basic architecture applied a conventional ohc configuration which made it a little taller than the Rekord's petrol engines, and diesel powered Rekord Ds are therefore easily distinguishable by the hump shaped ridge along the centre of the bonnet/hood.

For certain export market, notably Italy, where the 2-litre engine size was a critical threshold in terms of car tax rates, a smaller diesel unit became available from December 1974. The smaller unit shared the 85 mm stroke of the 2068 cc unit, but the bore was reduced from 88 mm to 86.5 mm, giving rise to a 1998 cc overall displacement. Maximum power in the smaller diesel came down from the 2068 cc car's 60 PS (44 kW) to 58 PS (43 kW). This was a first outing for the 2-litre diesel engine which from 1978 was offered in a diesel powered version of the Opel Ascona.

Ranger

The Ranger was a sedan assembled in small quantities by GM at their plants in Antwerp from 1968 and in Biel from 1970. There were two Rangers built in Europe, the first of which shared most of its panels and many of its underpinnings along, in Europe, with its engines with the Rüsselsheim built Opel Rekord C.

The second Ranger replaced the first in 1972 and was closely based on Rüsselsheim's Opel Rekord D. This second Ranger, known as the Ranger B, was built only at the Antwerp plant. It was first shown alongside the Rekord D at the 1972 Geneva Salon.^[5] It was available with the 1697 cc (83 hp) or 1897 cc (97 hp) four-cylinder engines from the Rekord, or two versions of the 2.5 litre six-cylinder engines as fitted to the Rekord's more luxurious sibling, the Opel Commodore.^[5] The Ranger B had twin headlights in place of the Rekord/Commodore's single rectangular lights, repositioned front direction indicators and a reworked front grill with a horizontal bar. There was a stylish raised section on the bonnet/hood which was different from the one used on diesel-engined Rekords, and the rear panel also incorporates detail differences. The Rangers were not strikingly more expensive than equivalently powered Rekords and Commodores, but nor were they perceived as sufficiently differentiated, and Rangers were quietly withdrawn from the showrooms by late 1975.

Chevrolets in South Africa and Iran

In South Africa, December 1972 saw the introduction of the Chevrolet 3800, and the Chevrolet 4100.^[6] In 1973 the four-cylinder 2500 version arrived, replacing the Rekord C-based Ranger. This smaller engine was a four-cylinder iteration of the 3800 straight-six. The engines were indeed sourced from Chevrolet but the cars were otherwise simply locally produced versions of the Opel Rekord D from which, apart from the engines, they differed very little. The 3800 and the 4100 were mostly the same, with the 3800 receiving a more spartan interior with vinyl seats and without standard head rests, and with different hubcaps.^[6] As with the European Ranger, they have twin round headlights rather than the Rekord's rectangular units. Engine outputs are 104.4 and 115.6 kW (142 and 157 PS; 140 and 155 hp) respectively.^[6]

The 2500, which arrived a bit later to help replace the Firenza 2500, was also available as a station wagon.^[7]

The big Chevrolet engines necessitated a bonnet with a "power bulge", although it is wider and lower than the bulge used on the Rekord Diesel's bonnet. They also had larger fuel tanks as petrol was subject to market controls in South Africa at the time. The suspension was uprated, and used locally developed variable-rate coil springs.^[8] The six-cylinder engines were built in South Africa but had hitherto been restricted to installation in larger, Holden-sourced cars.^[9] This series was South Africa's number one seller in 1975, although it dropped to third the next year and all the way to fifteenth in 1977.^[10] Larger cars received an ever-smaller market share in South Africa as sanctions began to kick in and gas prices increased steadily. It was replaced this year by the Chevrolet Rekord, a rebadged Rekord E with a Chevrolet four-cylinder.

The Rekord D was also assembled in Iran (before the revolution) from 1974 until 1977, albeit powered by six-cylinder engines. In Iran, the car was branded as the "Chevrolet Royale" or as the "Chevrolet Iran" and was assembled by Iran General Motors.^[11]