The Saab B engine is based on the Triumph Slant-4 engine

Triumph Slant-4 engine

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....

 and replaced their aging two-stroke engine. When it was decided to develop a new Saab

Saab

Saab AB is a Swedish aerospace and defence company, founded in 1937. From 1947 to 1990 it was the parent company of automobile manufacturer Saab Automobile, and between 1968 and 1995 the company was in a merger with commercial vehicle manufacturer Scania, known as Saab-Scania.-History:"Svenska...

 model in 1964, the Saab 99

Saab 99

- Development :On April 2, 1965, Gudmund's day in Sweden, after several years of planning, the Saab board started Project Gudmund. This was a project to develop a new and larger car to take the manufacturer beyond the market for the smaller Saab 96...

, the decision was also made to give it a modern four-stroke engine. A contract was signed with Triumph

Triumph Motor Company

The Triumph Motor Company was a British car and motor manufacturing company. The Triumph marque is owned currently by BMW. The marque had its origins in 1885 when Siegfried Bettmann of Nuremberg initiated S. Bettmann & Co and started importing bicycles from Europe and selling them with his own...

 to deliver their soon to be complete 1.5 liter engine to use in the Saab 99. The engine was enlarged to 1.75 liters before delivery started, and later enlarged again to 1.85 liters. In 1972 Saab begun domestic production of the engine, because of reliability problems with the Triumph-made units, effectively creating the Saab B engine.

This engine shared much with the original Triumph design, including bore centers and bearings, but was substantially redesigned. The redesign kept the unusual waterpump arrangement, which consisted of a cast aperture in the block, and the pump shaft with bearing, seals and impeller

Impeller

An impeller is a rotor inside a tube or conduit used to increase the pressure and flow of a fluid.- Impellers in pumps :...

 pressed into the aperture. The pump is driven by a jackshaft and helical gear. Later B engines used a fine tooth gear which is easily damaged and is a weak link in an otherwise very reliable engine.

In 1977, Saab added a turbocharger

Turbocharger

A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...

, creating one of the earliest turbocharged engines in volume production. This was placed in the Saab 99

Saab 99

- Development :On April 2, 1965, Gudmund's day in Sweden, after several years of planning, the Saab board started Project Gudmund. This was a project to develop a new and larger car to take the manufacturer beyond the market for the smaller Saab 96...

 and early 900 Turbo models.

Saab-Valmet developed in late 70's also a dual-fuel version which was able to use kerosene or turpentine alongside with gasoline. Low compression ratio for 67 octane kerosene was achieved by using turbo engine pistons. Engine had also electronic ignition also used in the turbo engine. Switch between gasoline and kerosene was automatic but driver was able to force gasoline-only mode with a manual switch. With kerosene engine produced 85 hp at 5600 rpm and was available only in Finland with 99 GL.

In 1981, Saab began lightening and redesigning the engine, creating the Saab H engine

Saab H engine

The Saab H engine is a redesign of the Saab B engine. Despite the name it is not an H engine, but a slanted inline-4. The H engine was introduced in 1981 in the Saab 900 and was also used in the Saab 99 from 1982 onwards and the Saab 90. It continued in use in the 900/9-3, 9000, and 9-5...

.