Alonso and Button were both penalised at the recent round in Austria for using their fifth engine of the year - the standard regulations allow four - but the revised rules have been retroactively applied to Honda, who returned to Formula One racing this season with McLaren, ‘for the sake of fairness’.
It means neither McLaren driver will receive grid penalties for using the new units - expected to be of unchanged specification - in Budapest, where the team hope the Hungaroring's high-downforce characteristics will be well suited to the MP4-30.
Honda have struggled to extract reliability or performance from their power unit, and McLaren have scored just five points this season, putting them ninth in the constructors’ standings.
