Eric Boullier has warned that Honda will not be unveiling a "revolution" when they are ready with a new specification of their Formula 1 power unit.
McLaren and Honda figures have played down Fernando Alonso's claim that an upgrade will definitely make its debut in Canada.
"The new engine is coming, but it will not be a revolution," team boss Boullier is quoted as saying by Italy's Autosprint.
However, there are positive signs. Honda and Renault have improved markedly since last year, and Renault's latest step in Monaco was achieved by using just three performance 'tokens'.
"Don't forget that we used a large number of tokens late last year, but we couldn't produce all the parts on time and only tried one of them in practice," said the French marque's Remi Taffin.
"We were criticised for it, but we could live with it because we knew that it would help us in 2016. It was the foundation of the current engine," he told Germany's Auto Motor und Sport.
The Canadian Grand Prix will take place on June 12.
