The Triumph Slant-4 is an engine developed by the UK engineering company, Ricardo, for Triumph and Saab. Initially offered at 1.7 L (1709 cc) for the Saab 99, the company continued development 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 and Panther Rio (1975-1977).

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.

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 Ricardo design, including bore centers and bearings, but was substantially redesigned. The Saab B engine was replaced by the related Saab H engine.