gasoline engine vs petrol engine

gasoline engine and petrol engine both are nouns.

Word	Noun	Adjective	Verb	Adverb
gasoline engine	Yes	No	No	No
petrol engine	Yes	No	No	No

As nouns, gasoline engine and petrol engine are synonyms defined as:

gasoline engine and petrol engine: an internal-combustion engine that burns gasoline; most automobiles are driven by gasoline engines

gasoline engine (noun)	petrol engine (noun)
an internal-combustion engine that burns gasoline; most automobiles are driven by gasoline engines	an internal-combustion engine that burns gasoline; most automobiles are driven by gasoline engines