text: 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_77 (valvetrain VARCHAR, fuel_system VARCHAR)
  ### Question:
  What Valvetrain has a fuel system made up of petrol engines?
  ### Answer:
  SELECT valvetrain FROM table_name_77 WHERE fuel_system = "petrol engines"