In the SGA episode "Before I Sleep" we learn that the Ancient known as Janus is the one who created the puddle-jumper time machine. It would appear that his efforts were universally condemned by the other Ancients, despite the fact that their city was under constant attack and their colonies and outposts in ruins.
MOROS: No. Enough of this tampering with time. Causality is not to be treated so lightly.
JANUS: No-one's treating it lightly.
MOROS: You are, with your insistence on continuing with experiments -- despite the condemnation of this Council. We ordered
you to cease these activities and yet here we sit, face to face with a
visitor from the future who arrived here in the very machine you
agreed not to construct.
When Weir arrives in a time-jumper, The Council of Ancients immediately destroy it. Janus manages to get Weir back to her original time (kinda) by traveling the long way around, placing her into a stasis pod with instructions on how to prevent the city from drowning, as it did in her original timeline.
His parting words are that he intends to continue his efforts to create a time-ship, efforts that were obviously successful given that SG1 subsequently locates and uses it. There is, however, no special indication that he used the ship himself to escape into the past or the future:
(In Central Control, Past-Elizabeth is lurking out of sight of the
departing Atlanteans. Janis is removing some glass control panels from
the consoles and putting them into a carrying case.)
PAST-WEIR: What's all that?
JANUS: My research.
WEIR: You're gonna build another time ship.