During V12, V10 & V8 naturally-aspirated engines era, all Formula 1 engines must show the manufacturers brand on their cylinder head casing or chambers.
Only Honda later Honda RBPT and Mercedes-AMG HPP has a engine brand logos on their engines in the V6 turbo hybrid era.
Formula 1 engines usually required to show the car/engine manufacturers logo on their engines (chambers or cylinder casing) during pre-V6 turbo hybrid era. Since the era of V6 turbo hybrid from 2014 to present, Formula 1 engines seldom to show the brand logos even not showing like Renault and Ferrari and only Mercedes-AMG HPP and Honda later Honda RBPT show the brand logos despite smaller logo.
In the V12, V10 and V8 naturally-aspirated era, all Formula 1 engines must show the manufacturers brand on their cylinder head casing or chambers.