some can be tuff. the toughest i came across was a 2jz on an engine stand. we had "darth" ( 1" air wrench with gobs of power and exhausts air constanly like darth vader) and it could not bust the crank bolt after repeated 10 - 20 sec bursts. didn't want to break the bolt so decided short bursts was the way to go. After about 10 - 20 attempts in short bursts "darth" was defeated. The only bolt i ever heard it could not back out. I wouldn't believe if i didn't see it myself. Darth prob cranks out 1200+lbs max. Apparently the tech before had over tightened severly and clearly did not know how to properly torque down, lol.

So to remove we came up with a massive lever to gain as much torque as humanly possible. Massive snap on breaker bar with a 12ft (it was very long) hollow bar extending the breaker bar's leveraging power. So after about 30 min the bolt was removed w/o issue but with lots of man handling. Needless to say the vehicle does not have any problems with the crank bolt and is still driven to this day.

PM me maybe i can assist with my air compressor.