Engine

On the Saab 900, the engine output is transmitted across a clutch and a primary chain transmission at the front of the engine to the gearbox and differential located below the engine and integrated within it, providing good cooling of the clutch. A compact power unit gives more interior space and better close up visibility.

To lower the centre of gravity and allow for a low bonnet line, the engine is sloped at 45 degrees. The cylinder head is of cross-flow design and supports a direct acting overhead camshaft.

All Saab 900 models are powered by a liquid-cooled, four cylinder, inline engine with a swept volume of two litres. The engine is integrated with the clutch, gearbox and differential into a lightweight power unit that occupies a minimum of space.

The combustion chambers are of cross-flow type, with the intake and exhaust ports located on opposite sides of the cylinder head. This arrangement ensures good cooling of the cylinder head at high engine speeds. Moreover, the operating temperature of the carburettor is reduced, which results in stable, reliable performance, even at high engine loads.

The ability of an engine to run at high speeds is largely dependent on the piston stroke. Since the piston stroke of the Saab engine is only 78 mm, the mean piston speed and mass forces are moderate, even at high engine revs. So the Saab 900 can take sustained high-speed cruising in its stride.

The overhead camshaft actuates the cam followers directly, without intervening push-rods and rocker arms. The camshaft is driven by a pressure-lubricated chain-a silent, reliable and maintenance-free drive arrangement.