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Crank pulley came loose f#[email protected]

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Old 07-17-2017, 12:02 PM   #1
Chad Dallas
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Default Crank pulley came loose f#[email protected]

Ok guys hopefully I can get some insight as to how badly I'm screwed well here goes somehow the oem crank bolt came loose so I purchased a new crank bolt as for they only have a single use torque spec tightened it down approx 240 lbs torque and put locktite on it as well after bolt 50 miles I started hearing a tapping noise so immediatly brought back home. After removing the serpentine belt I found out tgat tge crank pulley is loose but the crank bolt is still tight hope I haven't messed the crank up any input guys?
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Old 07-17-2017, 12:16 PM   #2
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Stock balancer? If so look to see if the outer ring moved in or out
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Old 07-17-2017, 01:25 PM   #3
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If the car still had the factory balancer it probably failed and either moved back against the engine or forward against the rack. C5 balancers are a very weak point and there are dozens of threads here about the outer ring separating from the inner hub that is pressed onto the crank snout and held there by the bolt you replaced.

When you replace it you will do yourself a favor if you use aftermarket rather than OEM if you plan to keep the car. Many threads also about replacement OEM balancers that failed soon after their install.
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Old 07-17-2017, 01:47 PM   #4
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If it hasn't worked itself forward or backward yet, you'll be fine. Get it replaced and grab an ARP crank bolt and a Powerbond balancer. There exists a ton of aftermarket balancers, but a nice powerbond unit will be fine at stock power levels.
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Old 07-17-2017, 02:59 PM   #5
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I really appreciate yiur guys input I'm not quite sure by seperation is doesn't seem to be but I could ve wrong I took some pictures hope this may help.


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Old 07-17-2017, 03:33 PM   #6
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See the rubber coming out? How much does it wobble while running?
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Old 07-17-2017, 03:38 PM   #7
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See the rubber coming out? How much does it wobble while running?
it wobbled about a quarter inch last i checked now the belt is off still about 1/4 inch left to right?
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Old 07-17-2017, 03:41 PM   #8
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it wobbled about a quarter inch last i checked now the belt is off still about 1/4 inch left to right?
yes i do see it thank you for pointing that out
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Old 07-17-2017, 03:44 PM   #9
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Time for a new one.. If you are staying stock the power bond pulley and the ARP bolt is what I would get
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Old 07-17-2017, 05:00 PM   #10
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Quote:
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...... torque spec tightened it down approx 240 lbs torque .....
That is not correct. The 240 lb-ft is applied to the old bolt during the installation process, which is then removed and replaced with the new bolt. The new bolt is then tightened to 37 lb-ft followed by a 140 degree rotation. That is likely the issue and why it came loose. Question now is if it spun on the crank, and if so, if it damaged the hub of the harmonic damper requiring replacement with a new one. This is a rather precise interference fit so spinning on the crank will cause issues with that fit.




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Old 07-18-2017, 07:14 PM   #11
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Ok so arp bolt it is with an aftermarket balancer but as far as pinning the crank im not sure? Can one of you guys help me understand this process?
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Old 07-18-2017, 07:21 PM   #12
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Ok so arp bolt it is with an aftermarket balancer but as far as pinning the crank im not sure? Can one of you guys help me understand this process?
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Old 07-18-2017, 07:36 PM   #13
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Quote:
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Ok so arp bolt it is with an aftermarket balancer but as far as pinning the crank im not sure? Can one of you guys help me understand this process?
The GM design for the crank snout and the balancer that goes on the end of the snout is that it does not have the keyway that older engines once had that kept the balancer from spinning on the crank snout under extreme conditions. Instead the LS1 relies on an interference fit of the balanced and the crank snout and uses a torque to yield bolt and washer to retain the balancer to the crank. In forced induction applications or very high HP applications it is still possible to cause the balancer to spin on the end of the crank with the GM design.

Here is a link with some images of what crank pinning is all about:

https://images.search.yahoo.com/sear...g&action=click

Basically you add a pin at the mating surface of the balancer and crank snout to prevent such spinning.

If you are not running some type of forced induction or do not have high HP you probably do not need to pin the crank. It is a safety feature to prevent spinning which could damage both the balancer and crank snout. If that were to happen the cost of repairs would far exceed the cost of the pinning....................
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Old 07-19-2017, 07:46 AM   #14
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Note that my post above is for stock parts, the ARP bolt is not TTY and uses the ARP lube and a specified torque value. Depending on which aftermarket harmonic dampener you are installing, the key for pinning may already be machined in place to use the ATI pinning kit.
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Old 07-19-2017, 09:09 AM   #15
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Quote:
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Ok so arp bolt it is with an aftermarket balancer but as far as pinning the crank im not sure? Can one of you guys help me understand this process?
Totally unnecessary with a stock setup.
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