Nissan Cedric
The SD20 is a naturally aspirated straight-four diesel engine with a bore and stroke of . It had three main bearings. The Diesel versions of the Nissan Cedric in the 1960s until the early 1980s used this engine, which produces at 4,000 rpm. It was first seen in a passenger car in June 1964, when it was fitted to the QGS31 Nissan Cedric.