The four-cylinder 2 litre engine of the first Volvo series of cars had just about started to rev up when it was replaced with a bigger, smoother and more powerful six-cylinder engine, just like those that many of Volvo's American competitors were beginning to introduce. 2009 marks the 80th anniversary of the DB engine and since 1929, apart from a ten year gap in 1958-1968, Volvo cars have been off...