Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_86 (year INTEGER, engine VARCHAR)
### Question:
What is the average year for Maserati Straight-4 Engines?
### Answer:
SELECT AVG(year) FROM table_name_86 WHERE engine = "maserati straight-4"