Nissan Diesel UD

Although Japan had mechanised in the early 20th Century its motor manufacturing capacity didn’t catch up to that of Europe and the USA. There were small manufacturing efforts at local designs, but the Japanese seemed largely content with locally assembled European and North American cars, trucks and buses, until the early 1930s.

Japanese manufacturers were able to examine these imported vehicles and develop their own products.

One homespun maker was the Kaishinsha Motorcar Co that in 1925, changed to DAT Motorcar Co.  Because there was little demand for passenger cars this company concentrated on making small trucks. 

In the background, in 1928, a separate industrial group was forming: Nihon Sangyo. The name ‘Nissan’ originated during the 1930s as an abbreviation of the group name.

In 1930, the Japanese government created a ministerial ordinance that allowed cars with engines up to 500cc to be driven without a licence. DAT began development of a line of 495cc cars to sell in this new market segment, calling the new small cars ‘Datson’ – meaning ‘Son of DAT’. The name was changed to ‘Datsun’ two years later in 1933, when Nissan Group took over DAT.

The Nissan Group eventually grew to include 74 firms and became the fourth-largest in Japan during World War II.

In 1934 Nissan released the semi-bonneted 80-Series 11/2-tonner, powered by a side-valve, 3.7-litre, six-cylinder petrol engine, with a four-speed transmission and hydraulic brakes. A bonneted version was also released and both vehicles later served with the Japanese Imperial Army in China and in the Pacific Theatre.

In 1935 a separate company, Nihon Diesel Industries Ltd, was set up to produce engines under licence from Krupp-Junkers AG in Germany. In 1936 the company started production of KD-series two-stroke diesel engines that later became branded Uniflow-scavenging Diesels (UDs).

In 1936, the Japanese government passed the Automobile Manufacturing Industry Law, which was intended to promote the domestic auto industry and reduce foreign competition. It was also part of thinly veiled preparations for Pacific Area military conquest. By 1939, foreign manufacturers had been forced out of Japan.

In 1940 production of Nihon Diesel UD 4.5-ton-payload TT6 series trucks started and, after the War, in 1949, production of 7.5-ton-payload TN93 series trucks started. This model had the largest payload capacity in the Japanese market and it was joined by the nation’s first monocoque-type BR3 series buses with rear-mounted engines. 

Over at Nissan, after Japan went to war with China in 1937, passenger car production was restricted, so by 1938, Datsun’s Yokohama plant concentrated on building light trucks for the Imperial Japanese Army. When the Pacific War ended, Datsun provided small trucks for the Occupation Forces.

In 1950 the company name of Nihon Diesel Industries changed to Minsei Diesel Industries, Ltd and, in 1953, the Nissan Motor Company took an equity stake in the business. Two years later Nissan-Minsei Diesel Sales Co Ltd was set up as joint Nissan-Minsei endeavour to market UD trucks.

In 1955 the production of various trucks and buses with 100hp UD3, 130hp UD4 and 210hp UD6 engines began. In 1957 the development of Japan’s first RFA series air-suspension buses and 10-ton-payload 6TW10 series trucks called ‘Jumbo’ in some overseas markets began.

In 1960 the company name was changed again, this time to the Nissan Diesel Motor Co and the joint venture marketing arm was renamed Nissan Diesel Sales Co Ltd. The truck branding was changed from Minsei to Nissan Diesel. New forward-control trucks and prime movers were also introduced. 

In the very early 1960s there was realisation that two-stroke diesels were not a long-term proposition, so in 1963, the initial production of compact four-stroke 50hp SD20 and 55hp SD22 diesel engines began. At the same time, 70 to 80-ton crane-carrier truck series were introduced to the line up. 

1969 saw the introduction of four-stroke 170hp PD6 and 125hp ND6 diesel engines for heavy-duty vehicles.

In 1972 Nissan Diesel launched its V-type 270hp RD8 and 330hp RD10 diesel engines. In 1973, light-duty trucks were produced for Nissan Motor Co Ltd. In the same year, UD Australia was established, in a sales, parts and service agreement with Westco Motors.

UD’s Australian range of CK, CW4O, CW45 and CW51 models gained instant acceptance and UD became the leading heavy-duty Japanese truck importer. In eight years UD Australia sold more than 10,000 trucks.

In 1979 the 145hp CM90 nine-tonner was released and in 1982 came a new COE cab for CWA52/45 series trucks and CKA-T series truck tractors, and  new U(A)21, U(A)31, RA51 series buses. 

Nissan Diesel formed an engine development agreement in 1989 with Iveco of Italy to jointly develop low-pollution diesel engines. They were called Cursor by Iveco.

In 1995 Nissan Diesel produced its two millionth vehicle since commencing production in May 1950. The Dongfeng Nissan Diesel Motor Co Ltd joint venture company with Sumitomo Corporation and China’s Dongfeng Motor Corporation was formed in 1996.

In 2000 Nissan Diesel introduced new heavy-duty trucks for Japan and Asian countries and also acquired the sales operation from Nissan Diesel Sales Co Ltd. In 2003, Nissan Motor and Nissan Diesel reached a basic agreement on a light-duty truck joint venture.

Nissan Diesel was purchased by the Volvo Group in 2007 and was a subsidiary until sold off to Isuzu in 2020.

UD Down Under

Japanese-market specifications suited most of UD’s target market in Australia, but linehaul capability proved elusive.

By 1998, after the failure of successive turbo sixes, UD’s massive V8 and a brief flirtation with Cummins’ 14-litre power to penetrate this segment, UD Australia engineered a Detroit Diesel Series 60 into the CW frame, with 430-470hp on tap. 

This CW S60 truck had a lighter, Rockwell RT-46-160 drive tandem and Hendrickson HAS460 air/leaf suspension. While not having more horsepower than the UD V8 the S60 had more torque and Jake Brake engine braking.

The truck had a two-year production life, before UD launched its GE13TD engine – the result of the Iveco engine development deal – in 2002.

Here are two UD historic videos: