I have seen the threads in stock Pontiac crankshafts strip out of the crank nose at the first 1/4"-1/2" of the threads. Two things generally cause this. 1. Using a balancer puller with a tapered nose that is too small for the large Pontiac size hole. The tapered nose goes too deep and snags-up the first couple threads in the crank nose. 2. Using the factory bolt to push the harmonic balancer back on during reassembly. If you don't get the balancer started at least 3/4" with a block of wood and a hammer, or better yet with a proper installation tool, the bolt will not engage enough threads and chew up the first several threads. My advice is to run a 5/8" fine thread bottoming tap into the crank nose to clean-up the threads, and then install the balancer properly and use a new bolt. Worst case situation, you can repair the crankshaft nose with a coil insert or a solid insert. It's very important not to bottom the bolt as mentioned and verify a minimum of 160 ft. lbs. with light oil on the threads and under the head between the washer,.
|