Triumph Slant-4 engine

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The Triumph Slant-4 is an engine developed by Triumph. According to Triumph historians Graham Robson and Richard Langworth in Triumph Cars, the complete story, the engine was developed in-house by a design team led by Lewis Dawtry and Harry Webster. The UK engineering and consultancy company Ricardo, which did have a general engine-development contract with Triumph, was not directly involved with its design, but was usually kept informed of anything new being planned. Ricardo was involved in developing a new engine for Saab, as a replacement for their aging two-stroke units. When that development proved too expensive and risky to produce, Ricardo, knowing the Slant-4 was almost ready for production, brought Saab into contact with Triumph. Saab first used the Triumph Slant-4 at 1.7 L (1709 cc) for the Saab 99. Only later, as production capacity increased, did it become available in Triumphs. Development continued into the 1990s. The engine is a straight-4 with the cylinders tilted at 45 degrees (actually a half Triumph V8).

Variants of the design were also used in the Triumph Dolomite 1850 and Sprint, early Triumph Stag, Triumph TR7 and Panther Rio (1975-1977).

[edit] Triumph Sprint

Triumph Motor Company added unique SOHC 4-valve cylinder heads to the Slant-4 for 1973's Dolomite Sprint. This is regarded as the first mass-produced multi-valve engine.

[edit] Saab B engine

Saab later increased the engine size to 1.85 L and in 1972 the company brought production in-house (to Scania) for the 2.0 L B version. This engine shared much with the original Triumph design, including bore centers and bearings, but was substantially redesigned. The Saab B engine was replaced by the related Saab H engine.