I searched around a bit, but didn't exactly find my answer. A few years ago, My balancer nut loosened up and I had a terrible (duh) vibration in the motor. I luckily discovered what it was and tightened it up. All was fine, but the pulley/balancer was a bit wobbly from that point forward. So this weekend I heard/felt the same thing again. So I drove home and got out the 1 13/16 socket again. I put it on the nut, and it just turned the crank, but the balancer was loose. So I got out my impact wrench and tighted it up. Now it's tight, and the pulley doesn't wobble. But now i'm a bit concerned I might have buggered up the threads in the end of the crank. Is it common for these nuts to come loose? Am I worried about nothing? I plan on rebuilding this motor next winter, but I want to reuse the crank and balancer.