Lotus 907

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1974 Jensen-Healey engine w/dual side draft Zenith-Strombergs for North-America
The Lotus Type 907 twin-cam engine fitted with European spec Dellorto carburetors in a Jensen Healey

The Lotus 907 was an engine designed and manufactured for automotive applications by Lotus Cars. It was an original design, 4 cylinder, dual overhead cam, 16 valve all alloy powerplant. It displaced 1973 cc and developed approximately 144 bhp (107 kW) with dual side-draft Dell'Orto carburetors or horizontal Zenith Stromberg carburetors for US cars. It was nicknamed "The Torqueless Wonder" for its lack of bottom end but good high end horsepower.

History[edit]

The Lotus 907 was the first production variant of the Lotus 900 series engine and the Jensen-Healey was the first production car to receive the Lotus 907.

It is said[1] that when Vauxhall unveiled its new slant-four engine at the 1967 Earls Court Motor Show its bore centers were exactly the same as those proposed by Lotus. Colin Chapman immediately negotiated a deal with Vauxhall to buy some of their cast-iron blocks so that development of Lotus' own aluminum cylinder head could be sped up to produce the 907 engine.

Lotus Esprit[edit]

The original Lotus Esprit, the Lotus Elite, and the Lotus Eclat were fitted with a 907 engine. Developments to this engine resulted in the subsequent type 910, the 912 and the V8 type 918.

Problems[edit]

Oil leakage was commonplace in the first few years of production, though the problem was eventually addressed by aftermarket cam cover gaskets made from reusable rubber.[2] Later 900 series Lotus engines included a revised cam tower that greatly improved the cam cover sealing design. The later cam towers can be retrofitted to the earlier 907 engines. Early Jensen-Healey engines (1972–1973) had oil supply issues that made the oil pressure slow to build on start-up.[3] Some early engines also had issues with oil drainage which resulted in too much oil being retained in the cam carriers.[4] Differences between early and late 907 engines included rope seals for the rear of the crankshaft versus regular spring-loaded rubber lip seals for the rear of the crankshaft on later 907 engines.

References[edit]

  1. ^ Adcock, Ian. Lotus Heritage. Osprey Automotive, 1995 (ISBN 978-1-85532-508-1), p. 38.
  2. ^ Cam cover gaskets; Kemp High Performance Ltd- Retrieved 2013-12-20
  3. ^ Lotusespritturbo.com; 907 engine- Original article by Lloyd McNell (ClassicCar Magazine 2000)- Retrieved 2013-12-20
  4. ^ Lotusespritworld.com; 907 oil problems- Retrieved 2013-12-20