Penta DB was an engine model produced by AB Pentaverken. The 1929 introduced engine was a side-valve engine with a cast iron block and seven main bearings, and the first straight-6 engine used in Volvo's. Four other variants followed after. These engines powered all six-cylinder Volvo passenger cars and taxi cabs, as well as the company's small trucks between 1929 and 1958.
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Penta DB Wikipedia(Text) CC BY-SA