By Abhishek Takle
SUZUKA, Japan, Oct 7 (Reuters) - McLaren's Fernando Alonso will start this weekend's Japanese Grand Prix from the back of the grid after the Spaniard picked up a 35-place penalty when the team's mechanics fitted his car with a fresh power unit on Friday night.
The team broke curfew -- during which members associated with the operation of the car must leave the track -- after the engine the double world champion used on the opening day of practice suffered a hydraulic issue.
Rules restrict drivers to no more than four power units and its constituent components for the duration a season, and Alonso has long exceeded his allocation as McLaren continues to struggle with a lack of reliability from their Honda engines.
Sunday's grand prix at Suzuka is the home race for the Japanese manufacturer, who will part ways with McLaren at the end of the season after three years of dismal performances, with the Surrey-based team switching to Renault power units.
Honda will instead supply engines to Red Bull's junior team Toro Rosso, currently powered by Renault, whose Spanish driver Carlos Sainz has also been hit with a 20-place penalty for exceeding his allocation of engine components.
Mercedes driver Valtteri Bottas will also drop five places for an unscheduled gearbox change. (Reporting by Abhishek Takle in Suzuka; Editing by John O'Brien)