The difference to me, If I put it simply is: 1. It took a long time 2. It took time..this could be any amount of time..long OR short. Not specific. 3.It took time but not very long But to be honest, in the end it means what the speaker intended it to mean. One could consider an hour short and another could consider it long depending on the situation.

The second one should be just "time", not "a time". "time" and "some time" feel the same but I recommend using "some time". "A long time" could mean "some time" but could also be longer than "some time".