Time-study men, I now see, set up record year (8)
I believe the answer is:
horology
'time-study' is the definition.
I can't tell whether this definition defines the answer.
'men i now see set up record year' is the wordplay.
'men' becomes 'OR' (military abbreviation for Other Ranks).
'i now' becomes 'oh' (I can't explain this - if you can you should believe this answer much more).
'see set up' says the letters should be written in reverse (in a down clue, letters go up).
'record' becomes 'log' (log is a kind of record).
'year' becomes 'y'.
'or'+'oh'='oroh'
'oroh' reversed gives 'horo'.
'horo'+'log'+'y'='HOROLOGY'
Can you help me to learn more?
(Other definitions for horology that I've seen before include "Art of designing and making clocks" , "The art of measuring time, or of making clocks and watches" , "The art of clock-making" .)