When the Lister JP2 enhine starts, there is a lot of gearbox whine as the flywheel runs faster and the old engine builds up to speed. There is a charactaristic "thump thump" building up to a roar after which the driver reduces power and the noise descends to abarking tickover.
When working the engine again exhibits the charactaristic whine as it is put to work, and the sound of the barking, thumping cylinders at work is also to be heard.