a well jar has telescoping inner and outer elements having a torque transmitting connection therebetween . an intermediate member is rotatably mounted relative to the telescoping elements and is affixed in a longitudinal direction to one of the telescoping elements . a releasable latch is connected between the intermediate member and one of the telescoping elements . the intermediate member is rotatable relative to the telescoping elements upon a predetermined minimum longitudinal force applied between the telescoping elements . the rotation causes a release of the latch and movement of the telescoping elements to an impact of coacting impact faces on the telescoping elements . an improvement involves a time delay section connected between the intermediate member and at least one of the telescoping elements for restraining such relative rotation for a preselected time interval of application of at least such minimum longitudinal force . in addition the preferred embodiment has the time delay section and the latch located in a common chamber , and the time delay section includes a hydraulic time delay device that makes use of the same fluid as that used for lubricating the latch .