At the start of the 1930s Fritz Egnell lost control of Pentaverken and Göteborgs Bank acquired a majority holding. Every year the company produced more Volvo engines than Penta engines, and Volvo's financial interest in Pentaverken increased. The production of marine, industrial and car engines under one roof, was no longer as smooth an operation as it had been in the beginning.

Although time and motion studies and assembly-line production were introduced at an early stage - in 1930 - there were constant problems in the spring and summer which was the high season for Volvo and for other customers. Volvo was a demanding customer whose favors were being sought by many other Swedish companies and it was often necessary to work round the clock to complete its orders.

In 1935, Volvo took over completely and the company was renamed Volvo Pentaverken. In the same year Volvo moved a design and sales department to Göteborg and set up AB Pentaverken in Göteborg, the company from which AB Volvo Penta developed.