Crank Pulley Wobble
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6th Gear
Joined: Nov 2014
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Crank Pulley Wobble
I finally achieved the dreaded 50,000 mile mark on my 2005 Corvette and took my beautiful baby in for a check up. I was told that my crack pulley is wobbling slightly, but reading up on the issue I've seen that it's not a terrible thing in some first gen C6's but more so common in this gen and in some of them it's detrimental. Could somebody help me figure out if I should tighten and pin the crank or should I have the labor done the dealership is referring me to. My belt isn't chirping and before the dealership told me that my pulley wobbles I never even noticed.
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Wobbling HB outer pulley from the center rubber coming loose, and the HB crank bolt coming loose are two different issues.
There was a TSB on the cranks bolts, so if you think that its the bolt that is coming loose to allow the entire crank to walk forward on the crank that is one issue. A loose crank bolt is easy to pick up, since the entire HB will start to walk forward and back (watch the inner section and the alignment of the belt to the outer section pulley).
As for the outer pulley wheel wobbling while the inner section that is bolts to the crank is staying stationary, that is the HB going south instead.
So on that note, with the engine running, compare the outer wheel of the HB against the inner section of the HB. The HB did come with slight wobble on the very outer front surface, but the pulley grooves where running straight instead.
So watch the below video and note that the inner ring section is running/staying true, and its the outer pulley section that is moving/dancing all over the place on the inner section instead (rubber center piece is no longer correctly bonded to the inner/outer sections to hold them together correctly).
There was a TSB on the cranks bolts, so if you think that its the bolt that is coming loose to allow the entire crank to walk forward on the crank that is one issue. A loose crank bolt is easy to pick up, since the entire HB will start to walk forward and back (watch the inner section and the alignment of the belt to the outer section pulley).
As for the outer pulley wheel wobbling while the inner section that is bolts to the crank is staying stationary, that is the HB going south instead.
So on that note, with the engine running, compare the outer wheel of the HB against the inner section of the HB. The HB did come with slight wobble on the very outer front surface, but the pulley grooves where running straight instead.
So watch the below video and note that the inner ring section is running/staying true, and its the outer pulley section that is moving/dancing all over the place on the inner section instead (rubber center piece is no longer correctly bonded to the inner/outer sections to hold them together correctly).
Thread Starter
6th Gear
Joined: Nov 2014
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First, thank you for such a quick and informative response. Second, that explains everything perfectly. My inner ring is running fine without any wobbling while the outer ring has a slight wobbling to it almost exactly as in the video. If I read what you wrote correctly, then there isn't an issue with my HB after all just the mechanic that looked over my car didn't know what he was looking at, but would you recommend still getting it pinned to be safe?
Burning Brakes
Joined: Aug 2014
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From: Tampa FL
First, thank you for such a quick and informative response. Second, that explains everything perfectly. My inner ring is running fine without any wobbling while the outer ring has a slight wobbling to it almost exactly as in the video. If I read what you wrote correctly, then there isn't an issue with my HB after all just the mechanic that looked over my car didn't know what he was looking at, but would you recommend still getting it pinned to be safe?
2011 LS3 -15,000
mi
Last edited by HK770; Jun 2, 2015 at 07:53 PM.
Safety Car
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From: Bay Area CA
I think what Dano523 was explaining is that there could be two types of HB failures. First - HB bolt loosens up causing the inner hub of the HB to walk. Second - the outer ring portion of the HB wobbles due to failure of the silicone seal between the inner/ outer ring. Either way replace the HB and a new bolt.
Pinning the crank is normally done with higher HP engines or boosted engines.
Pinning the crank is normally done with higher HP engines or boosted engines.
Thread Starter
6th Gear
Joined: Nov 2014
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Thanks for all the help, I've got a trusty mechanic that said he'll help me put in the HB, I'm going to swap it with the ATI 917246 that HK770 recommended. It has better reviews and it's not the same stock one that the dealership wants to put in.
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Race Director
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Don't forget to change the HB oil seal on the front cover!!!!
If the HB comes with a key way slot, seal the slot with RTV, but not so much sealer that you are flowing it out the back side off the HB and it ends up in the oi pan.
Also, while you are there, pin the HB to the crank. The pin help to keep the HB from slipping on the crank under torque condition, which in turn help to hold the crank bolt to torque.
If the HB comes with a key way slot, seal the slot with RTV, but not so much sealer that you are flowing it out the back side off the HB and it ends up in the oi pan.
Also, while you are there, pin the HB to the crank. The pin help to keep the HB from slipping on the crank under torque condition, which in turn help to hold the crank bolt to torque.
Safety Car
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From: Opelika Alabama
Thread Starter
6th Gear
Joined: Nov 2014
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Thanks for all the help y'all, I got the new HB in and she's been running smooth for about a week. I went with the ATI 917246 that HK770 recommended. So far everything seems great, I'll give an update in about two months when I make my road trip down to Florida.
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Key feature the the ATI HB, the inertia weight ring is sistered between the inner and outer shell, with both shells being bolted to the hub assembly.
So no fear of the rubber adhesive like the Oem coming loose from the outer/inner sections of the OEM to cause the wobble problem in the first place.
As long as the damper bolts of the ATI are correctly torque and loctite in place, as well as using a ARP crank bolt (that does not get stretched to setting like the OEM bolt) is correctly torque, the ATI HB will last longer than the motor itself.
http://www.dragtimenews.com/dampers101.htm
The power bond unit is another good one, and instead of using damper bolts to hold everything together, it has a large C ring instead.
https://www.corvetteforum.com/forums...it-racing.html
So no fear of the rubber adhesive like the Oem coming loose from the outer/inner sections of the OEM to cause the wobble problem in the first place.
As long as the damper bolts of the ATI are correctly torque and loctite in place, as well as using a ARP crank bolt (that does not get stretched to setting like the OEM bolt) is correctly torque, the ATI HB will last longer than the motor itself.
http://www.dragtimenews.com/dampers101.htm
The power bond unit is another good one, and instead of using damper bolts to hold everything together, it has a large C ring instead.
https://www.corvetteforum.com/forums...it-racing.html
Last edited by Dano523; Jun 19, 2015 at 01:40 AM.
Le Mans Master
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From: San Diego
I ended up purchasing a used ATI balancer in the for sale section for $130 and ATI rebuilds them for $75 so $205 for a good ATI balancer isn't a bad deal?
Last edited by Brandon619; Jun 21, 2015 at 04:44 PM.
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St. Jude Donor '15
Le Mans Master
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From: San Diego
