Quote:
Originally Posted by SSHSSISS
I do have questions on step 70?
Sorry if this has already been covered.
Why did you need a new crank bolt;Is it just for insurance since the old bolt may have become damaged upon removal?
When pressing on the new balancer I can understand the longer M16 bolt to get the balencer halfway on and then using the old crank bolt to finish it off torquing it to 240ft/lbs.
But then I interpretted the next step is that you removed the same bolt you torqued down to 240 ft/lbs and then put in a new M16 bolt and torqued it to only 37 ft/lbs. and then another 140 degrees.
Is the 240ft/lbs done just to press the balencer in and since the old bolt has now seen better days it needs to be replaced and torqued to only 37 ft/lbs +140 degrees?
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The statement in bold is correct. The 240ft/lbs seats the balancer. The trick here is that GM used a torqued-to-yield design to get the preload on the bolt consistent. Similar to other bolts in the engine like heads, mains, con-rods I think, once it has been torqued to spec you can not re-use it. So the bolt actually physically stretches, and the properties change so the preload stresses will be different if you try to use it again. It's just convenient to use the old crank bolt, any bolt of the proper size will do for the 240 pass.
So yes, seat the balancer with 240 ft/lbs, remove that bolt, and seat a new one at 37 ft/lbs + 140 degrees