CREATE TABLE table_75416 ("Model" CLOB, "Engine" CLOB, "Displacement" CLOB, "Valvetrain" CLOB, "Fuel system" CLOB, "Max. power at rpm" CLOB, "Max. torque at rpm" CLOB)

What Valvetrain has a fuel system made up of petrol engines?
SELECT "Valvetrain" FROM table_75416 WHERE "Fuel system" = 'petrol engines'
SELECT "Valvetrain" FROM "table_75416" WHERE "Fuel system" = 'petrol engines'