There is a "cirakAla-", it's almost all commentarial.
And, "cirakAlabhAvana-" is, you guessed it, in the Cariyapitaka Atthakatha! eg. PTS p. 18: Tasso hi bodhisambhāresu bhāvanā sabbasambhārabhāvanā nirantarabhāvanā cirakālabhāvanā sakkaccabhāvanā cāti. Tāsu ‘‘kappe ca satasahasse, caturo ca asaṅkhiye’’ti iminā cirakālabhāvanā vuttā. ...
Rather an understatement for "a long time", huh?
There are other related ones, but dredging them all out is a chore at times. ...
And, Th-a-k, PTS ii 80: Dīghamaddhānanti cirakālaṃ anādimati saṃsāre aparimāṇakālaṃ.
Seems perhaps even longer. Is that possible?
Which is longer, an "incalculable" or an "immeasurable" length of time?