Crankshaft pulley stretch bolt removal

[littlepolo]

Cambelt, waterpump, etc. overdue for a change and cannot recall how I undid the crankshaft pulley stretch bolt last time. I have the locking bar and tried a long breaker bar with a 22mm 6 point socket to no avail. I think I might have hired an impact driver several years ago but not so easy to find a high-torque product available. What torque rating impact driver is needed to undo this bolt (I have a lilse harmonic balancer weighted socket ready).