Searching through Internet and books for Ojibwe clock time expressions I found there is no a single standard. Though the same words are used to express time, their place and grammatical forms in statements differ. Sometimes more than one variant is given here. And I'm not sure about of what dialect they belong to and if these are grammatical differences of dialects, or just the same thing can be said in several ways. Minnesota Ojibwe spelling is used for all the samples.
aaniish endaso-diba'iganeg? what time is it?
aaniin endaso-diba'iganeg? what time is it?
ningo-diba'iganed. It's one o'clock.
niizho-diba'iganed. It's two o'clock.
niso-diba'iganed. It's three o'clock.
midaaso-diba'iganed. It's ten o'clock.
midaaswi-ashi-bezhig (daso-)diba'iganed. It's eleven o'clock.
midaaswi-diba'iganed ashi-bezhig. It's eleven o'clock.
naawakwe. It's noon.
aabitaa-dibikad. It's midnight.
naawakwe-ashi-aabita. It's 12:30 afternoon. (=it's noon and a half)
midaaso-diba'iganed ashi-aabita. It's 10:30.
niizho-diba'iganed ashi-aabita. It's 2:30.
Time could be expressed with just telling what hour it is (1, 2, 3, etc), or also relative to time of the day - noon, midnight, etc. Saying what time is it A form is used. But B form is used with preverbs ishkwaa-(after), jibwaa-(before):
midaaswi-ashi-naano-diba'igaans ishkwaa-ningo-diba'iganeg. It's quarter past one (It's 1:15). (=it's 15 miutes after one o'clock)
ngodwaaso-diba'igaans ishkwaa-ningo-diba'iganeg. it's six minutes after one (It's 1:06).
niso-diba'igaans jibwaa-niizho-diba'iganeg. it's three minutes till two o'clock (It's 1:57).
aaniish pii? when?
aaniin (a)pii? when?
naazho-diba'iganeg. At two o'clock.
niizho-diba'iganeg. At two o'clock.
naazho-diba'iganeg eshkwaa-aabtaa-dbikak. At two o'clock in the morning. (=at two o'clock after midnight)
niizho-diba'iganeg noongom ishkwaa-naawakweg. At two o'clock this afternoon. (=at two o'clock today after noon)
biinish naano-diba'iganeg. Untill five o'clock.
naazho-diba'iganeg ningii-waabamaa inini. I saw the man at two o'clock.
biinish naano-diba'iganeg gidaa-oodetoomin. We could go to town until five o'clock.
Note that saying "at... o'clock" they use either changed B form or plain B form. Maybe it depends on a community or dialect. I don't know.
aaniish minik? how much?
aaniin minik? how much?
aaniin minik endaso-diba'igiiziswaan? How many hours?
aaniin minik endaso-diba'igan? How many hours?
aaniin minik endaso-diba'igaans? How many minutes?
aaniin apiichi gabeyi'iing gaa-anokiiyan? How long did you work?
aaniin minik endaso-diba'igan gaa-anokiiyan? How long did you work?
midaaswi-ashi-naano-giba'igaans gii-ayaa gwiiwizens. The boy was here for 15 minutes.
nishwaaso-diba'igan gii-anokii inini. The man worked for 8 hours.
nishwaaso-diba'igiiziswaan gii-anokii inini. The man worked for 8 hours.
(Most samples were taken from Nishnaabemwin Reference Grammar by J. Randolph Valentine (though spelling was changed into Minnesota Ojibwe), and from web sites http://www.ksc.nasa.gov/external/groups/naic.old/ojibway.htm (offline), and http://www.trentu.ca/faculty/rnl/lexicon.html)
For more examples of time expressions see also On the hour from Familiar phrases to facilitate conversation in the Indian language.