United Engine and Machine Company was started in 1922 in Fresno, California by Deuta Sulprizio, Sr. For eight years, the company continued to grow and build a reputation for the manufacturing of pistons. Then in 1930 the company was moved to San Leandro, California in order to supply OEM manufacturers located on the West Coast. The company continued to grow until the start of the World War II. During the war, the company's emphasis changed. No longer were they solely a piston manufacture. The company started supplying special marine applications for PT boats and some small munitions, such as incendiary bombs.