How much does an Asst. Professor - Mechanical Engineering make in Oregon? The average Asst. Professor - Mechanical Engineering salary in Oregon is $85,452 as of November 25, 2019, but the range typically falls between $71,610 and $101,410. Salary ranges can vary widely depending on the city and many other important factors, including education, certifications, additional skills, the number of years you have spent in your profession.