PA-28-181 instructor pilot reported an engine loud bang during the initial climb in the pattern; from a Tower controlled airport; on a training flight. The instructor took control from the student and notified ATC and reduced power to reduce the engine banging noise; and immediately returned to land on the takeoff runway in the opposite direction. The aircraft landed safely; and was able to taxi clear of the runway.

Narrative

While conducting training takeoff and landings; during climbout off of Runway XX reaching 2;100 feet turning from the crosswind to the down wind my student and I heard a loud banging noise from the engine. It took approximately 3 seconds for me to realize we were having a mechanical issue with our engine. I immediately took the controls reduced power and turned to the runway calling the ZZZ Tower advising them of the problem. The noise diminished with the reduction of power. I did not [request priority] on the radio for I was very busy calculating altitude and airspeed to make it back to the runway and communicating with Tower. I advised ZZZ Tower I was headed to the numbers on Runway X for landing. ZZZ Tower advised that I was cleared to land Runway X. I landed the plane and was able to taxi clear and back to the FBO ramp.ZZZ Tower personnel is great; and I am thankful to have them with me during this event. Engine noise was consistent with a broken piston rod or push rod from my experience.