Lotus 900 series

Lotus 900 series engines were designed by Lotus as their first self-developed engine, and due to similarities in dimensions and layout, Vauxhall/Opel/GM 4-cylinder iron blocks were used as testbeds for the Lotus DOHC 16 valve cylinder head. All of the production 900 series engines used Lotus' own aluminium block.

The 900 series engine was introduced in production form as the Lotus 907 in the 1972 Jensen-Healey, and went on to power Lotus into the late 1990s. It is regarded as the first modern DOHC, 16-valve production engine made. The Jensen-Healey was released for sale to the general public with the first 907 engine shortly before the Cosworth Vega which also had a DOHC, 16-valve engine. Pre-war DOHC 4 valve per cylinder production engines included the Duesenberg and the Stutz DV-32 straight-8 engines.

The initial 2.0 litre Lotus 904 engine was first used in the Lotus type 62 Europa racecar, and indeed used a Vauxhall iron block. The Lotus marketing designation for this engine was LV220 for Lotus/Vauxhall 220 bhp. According to Jeremy Walton this 220 bhp (164 kW; 223 PS) was developed at 8000rpm.

The Lotus 907 engine, the first production version, was 2.0 L (1973 cc) and was used in the Jensen-Healey and later Lotus Esprit, Lotus Elite and Lotus Eclat. Bore was 3.75 in (95.28 mm) and stroke was 2.725 in (69.24 mm), and a DOHC 4-valve head was fitted, one of the first in modern times. Breathing through dual carburettors, the engine in final form as used in the Esprit produced 160 bhp (119 kW; 162 PS) at 6500 rpm with 140 lb·ft (190 N·m) of torque. Initial figures for the Jensen-Healey version were 140 bhp (104 kW; 142 PS) and 155 bhp (116 kW; 157 PS) as used in the first Elite cars.

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