Sir Dhanjisha and Walchand Hirachand worked together for making passenger cars and diesel engines. They both are regarded as the pioneers of automobile era in India. In collaboration with Duncan Staten, Hindustan Engineering & Implement Company was formed by Sir Dhanjisha Cooper to make diesel engines in India. Engine parts like crankshaft, fuel pumps, valves, valve guides, bearings, piston rings, camshafts etc. were imported from overseas.
But the British did not want the 'natives' to make Engines. They worked to break the collaboration. However, a little later, Walchand met Sir Dhanjisha and agreed to collaborate. Jointly, Cooper Engineering Co. was formed in 1940, with Walchand Hirachand as Chairman and Sir Dhanajisha Cooper, Nariman Cooper, Lalchand Hirachand and Gulabchand Hirachand as Directors.
In 1942, Cooper company made the first Indian diesel engine and tested it successfully on a Morris car. The business flourished with more than 2000 employees, who were provided with all amenities in the industrial township to attract the best of talent. After the death of Sir Dhanjisha in 1947, Seth Walchand helped the family through royalty and kept the name Cooper in its establishments as a mark of respect for Sir Dhanjisha Cooper. Seth Walchand supported the family financially through a marketing agency till 1968. Seth Lalchand Hirachand gave a lathe machine to Sam N Cooper at a very nominal cost to start Satara Industrial Works in 1962.