Sort of motor available to directors (8)
I believe the answer is:
outboard
'sort of motor' is the definition.
(I've seen this before)
'available to directors' is the wordplay.
'available' becomes 'out' (I've seen this in other clues).
'to directors' becomes 'board' (board of directors).
'out'+'board'='OUTBOARD'
(Other definitions for outboard that I've seen before include "Engine external to the boat" , "Engine attached to boat" , "Small boat's motor" , "Detachable small boat motor" , "Engine mounted at the stern of a small boat" .)