Hi Tom, Better take off that harmonic balancer and have it rebuilt . Damper Dudes or other similar outfits take care of this. You cannot JB-Weld both halves together as you will be negating the damping properties. As stated in earlier e-mails, these dampers are prone to failure, and the timing mark is not necessarily accurate on any of them . ONLY WAY to make sure is to use a piston stop indicator on #1 cylinder and make sure the timing mark is accurate according to TDC. Out of 5-6 used dampers I had on the shelf, only one was accurate, others had moved by 5 / 10 / 20 degrees or more. All this to say - the old method of timing by "ear" might still be the best especially if you have not verified the accuracy of your timing mark using #1 piston at TDC . John