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Crank pulley/balancer bolt torque specs?

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Old 03-08-2006, 08:08 PM   #1
STLBLUES
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Default Crank pulley/balancer bolt torque specs?

Ok my balancer slipped and moved out after a cam swap. I have the rack moved out of the way and I am ready to wrench. I need to know what the torque spec is. I have seen 200 and 250 ft lbs listed. After you torque the bolt to 250 why remove it and use a new bolt?
I followed ls1howto and torqued to 200 then installed a new bolt and torqued it to 37lbs and then marked it and turned it another 140deg. My only mistake was no locktite because the new bolt looked like it had some on it from GM.
Does the balancer spin on the crank and back the bolt out? I know someone will mention crank pinning or ARP bolt. I also know tons of people do not have this problem after cam swaps using the stock bolt only. Does anyone have a better way to go at this? Or should I just repeat my steps and loctite it?
Thanks Steve
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Old 03-08-2006, 09:40 PM   #2
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You torque the balancer back on to 250ft lbs. Then use a new bolt to 37lbs then twist 140 degrees.

Yes the balancer can spin on the crank and cause the bolt to back out.

Did you re-use your balancer? I think this is the main problem. Re-using a balancer that has already been stretched onto the crank once will not hold the same again when stretched over the snout. I would always use a new balancer whether it was stock or not. Otherwise I would pin crank. Actually if I did this again I would key the crank anyways.

I feel your pain. My stock balancer failed in the rubber section and slid into the front engine cover. It did a lot of damage. While I was in there fixing it I did a cam swap. Getting everything out of the way then fighting with the bolt was a real experience.
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Old 03-08-2006, 09:49 PM   #3
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You have to use a new bolt because it is a torque to yield bolt.
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Old 03-09-2006, 12:13 AM   #4
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The crank bolt is suppose to strech when you torque it down. That is why you use the old bolt first. Trust me it is worth the time and money to use a old bolt. The previous owner of my car did that and it end up cost me a new motor
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Old 03-09-2006, 01:24 AM   #5
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My UD pulley bolt backed out twice this week- yesterday it was on the dyno when it happened. Turns out you can only use those stretch bolts once

like everyone else said, tq the crap out of the original bolt to get that pulley on good and tight, then pull teh bolt, put the new stretch bolt on (with loctite!!) and tq to 37ft/lbs- then another 140degrees, and hopefully it'll stay on.
Good luck getting that steering rack out of the way- its a real PITA!
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Old 03-09-2006, 03:18 AM   #6
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Quote:
Originally Posted by STLBLUES
Ok my balancer slipped and moved out after a cam swap. I have the rack moved out of the way and I am ready to wrench. I need to know what the torque spec is. I have seen 200 and 250 ft lbs listed. After you torque the bolt to 250 why remove it and use a new bolt?
I followed ls1howto and torqued to 200 then installed a new bolt and torqued it to 37lbs and then marked it and turned it another 140deg. My only mistake was no locktite because the new bolt looked like it had some on it from GM.
Does the balancer spin on the crank and back the bolt out? I know someone will mention crank pinning or ARP bolt. I also know tons of people do not have this problem after cam swaps using the stock bolt only. Does anyone have a better way to go at this? Or should I just repeat my steps and loctite it?
Thanks Steve

Been through this twice thanks to ####...pin that sucker, use new bolt and balancer to recomended specs w/red lock tight.
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Old 03-09-2006, 05:56 PM   #7
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Ok a new balancer will be purchased this week. I do not want a underdrive because I have enough hp as it is. I have the rack moved and a new bolt in hand. I think the new balancer and locktite will get me back on the road.
Anyone make a stock size balancer thats better than gms?
Thanks, Steve
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Old 03-09-2006, 07:31 PM   #8
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Quote:
Originally Posted by gonbad
Did you re-use your balancer? I think this is the main problem. Re-using a balancer that has already been stretched onto the crank once will not hold the same again when stretched over the snout. I would always use a new balancer whether it was stock or not. Otherwise I would pin crank.


I installed the ATI, and the interference called for is 0.0007 - 0.0009". I don't know what the stock balancer interference fit is, but I personally believe that they should not be re-used either.
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Old 03-09-2006, 07:38 PM   #9
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Quote:
Originally Posted by gonbad
You torque the balancer back on to 250ft lbs. Then use a new bolt to 37lbs then twist 140 degrees.

Yes the balancer can spin on the crank and cause the bolt to back out.

Did you re-use your balancer? I think this is the main problem. Re-using a balancer that has already been stretched onto the crank once will not hold the same again when stretched over the snout. I would always use a new balancer whether it was stock or not. Otherwise I would pin crank. Actually if I did this again I would key the crank anyways.

I feel your pain. My stock balancer failed in the rubber section and slid into the front engine cover. It did a lot of damage. While I was in there fixing it I did a cam swap. Getting everything out of the way then fighting with the bolt was a real experience.


Well said!
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Old 03-09-2006, 08:59 PM   #10
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Quote:
Originally Posted by STLBLUES
Ok a new balancer will be purchased this week. I do not want a underdrive because I have enough hp as it is. I have the rack moved and a new bolt in hand. I think the new balancer and locktite will get me back on the road.
Anyone make a stock size balancer thats better than gms?
Thanks, Steve
ATI makes a stock diameter balancer. Pricey bastard though if I remember correctly.
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Old 03-09-2006, 09:32 PM   #11
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Seriously guys, you replace the balancer just because you remove it? Must be something exclusive to a Gen III or newer. I've been working on SB Chevys for 30 years and never heard of having to do that. If you remove it with a puller, what damage have you done?
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Old 03-09-2006, 10:25 PM   #12
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Quote:
Originally Posted by kdub1
Seriously guys, you replace the balancer just because you remove it? Must be something exclusive to a Gen III or newer. I've been working on SB Chevys for 30 years and never heard of having to do that. If you remove it with a puller, what damage have you done?
The balancer is press fit with no key way. The only thing that holds it on is the bolt and a tight tolerance. I wish gm would have made it just like the old small blocks.
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Old 03-10-2006, 03:41 AM   #13
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Quote:
Originally Posted by STLBLUES
The balancer is press fit with no key way. The only thing that holds it on is the bolt and a tight tolerance. I wish gm would have made it just like the old small blocks.
And how!
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Old 03-10-2006, 08:25 AM   #14
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No keyway? No wonder guys are pinning the balancers. Thanks for the info.
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