Harmonic balancer bolt came unscrewed!!
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
Likes: 0
From: Camarillo CA
Harmonic balancer bolt came unscrewed!!
So, driving on the back roads yesterday with a brand new harmonic balancer that was installed 4 days ago. Lost my alternator and power steering, so I figured the belt was slipping. Turned around to try and make it home, and starting hearing and feeling a grinding noise! Pulled to the shoulder and popped the hood and could clearly see that the bolt for the harmonic balancer had come unscrewed and was grinding on the rack and pinion... Awesome. Bring out the flat bed. Any words of advice to pass along to the shop so this doesn't happen again? I told them they needed to use locktite on it. Does this happen with the summit racing or ATI balancers?
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 465
From: Southern Utah
After problems with the early '05s, GM added a diamond dust coated washer for the bolt. A new one is required any time the bolt is loosened. You might check this with the mechanic that replaced the balancer.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
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From: Camarillo CA
Thank you! I'll make sure they replace it this time. They warranty their work, so anything they do now should be at no charge. I also told them they needed to check for any other damage to the belts and such..
Racer
Joined: Aug 2008
Posts: 497
Likes: 21
From: Garner NC
They also have to be torqued down very tight, I think factory spec is well over 200 lb-ft. If not torqued to spec they can back out. Why GM didn't just use a keyway like on the millions of small blocks before the LS series I'll never know. Make sure there is no damage to the crank snout. If there is, this could turn into a major job real quick. You should be alright though since you caught it early.
Last edited by Paratrooper307; Dec 6, 2015 at 02:15 PM.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
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From: Camarillo CA
They also have to be torqued down very tight, I think factory spec is well over 200 lb-ft. If not torqued to spec they can back out. Why GM didn't just use a keyway like on the millions of small blocks before the LS series I'll never know. Make sure there is no damage to the crank snout. If there is, this could turn into a major job real quick. You should be alright though since you caught it early.
Race Director
Joined: Dec 2013
Posts: 12,505
Likes: 3,631
Diamond washer, new factory OEM bolt torqued to spec, and should not have a problem with it.
Best guess, they did not get a new diamond washer and new bolt, and tried to use the old ones instead. The problem with this, the OEM bolt and washer are a one time stretch to torque use only.
Best guess, they did not get a new diamond washer and new bolt, and tried to use the old ones instead. The problem with this, the OEM bolt and washer are a one time stretch to torque use only.
Melting Slicks
Joined: May 2005
Posts: 3,394
Likes: 12
From: Leon Iowa
St. Jude Donor '06-'07-'08-'09
Had the same thing happen on my C5 after I put a new damper on. I had he bolt tight and everything. I honestly think I must of not had the damper fully seated. After driving with the pressure of the bolt I think the damper finally seated doing so allowed the bolt to not be as tight since the damper moved inward. After that happened I made a specaisl tool and was able to tighten the bolt again and after that it never came loose again. That's what I'm betting happened. Had the same thing happen on my trans am but checked the bolt on it after a few hundred miles and noticed the bolt needed tightened a bit more. Sometimes it's hard to get them fully seated because they go on so hard.
Melting Slicks
Joined: Jun 2006
Posts: 2,499
Likes: 261
From: Miami Florida
What year car and what engine.
I have a heads and cam ls3 with aftermarket damper and ARP bolt and it came loose as well took out the bolt applied enough red thread lock torqued to 240 lbs. done.
Mechanic has to lock motor from turning to get the torque spec rite with a torque wrench not the impact gun.
I have a heads and cam ls3 with aftermarket damper and ARP bolt and it came loose as well took out the bolt applied enough red thread lock torqued to 240 lbs. done.
Mechanic has to lock motor from turning to get the torque spec rite with a torque wrench not the impact gun.
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Advanced
Joined: Mar 2014
Posts: 72
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From: Camarillo California
I'm sure they didn't torque it enough. I'm new to the area, and there isn't a corvette shop close by. This place was recommended and had great reviews. Try say they've done this job before, but I'm starting to wonder.. I'll have them inspect the crank snout to make sure. I shut her down immediately and had it towed, so it should be fine. I'll let you guys know next week. I'm off to England while she gets fixed
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
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From: Camarillo CA
It's a 2005 c6 base, so the 6.0.
Good stuff, thanks guys. I'm going to talk to them today, and this time I'll make sure they use a new bolt and diamond washer. And torque it correctly...
Good stuff, thanks guys. I'm going to talk to them today, and this time I'll make sure they use a new bolt and diamond washer. And torque it correctly...
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
Likes: 0
From: Camarillo CA
I talked to A&A a few weeks ago and they said they really only do super chargers and things like that. I guess I should have called them again and asked about the harmonic balancer specifically. If it goes bad again I'll definitely call them. We should go cruise some time!
Racer
Joined: Oct 2012
Posts: 278
Likes: 11
From: Sum Where Mid-Low 9'S
aftermarket damper and ARP bolt and it came loose as well took out the bolt applied enough red thread lock torqued to 240 lbs. done.
Mechanic has to lock motor from turning to get the torque spec rite with a torque wrench not the impact gun.[/QUOTE]
http://www.summitracing.com/parts/ar...2503/overview/
Mechanic has to lock motor from turning to get the torque spec rite with a torque wrench not the impact gun.[/QUOTE]
http://www.summitracing.com/parts/ar...2503/overview/
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
The factory bolt isn't supposed to be tightened to a torque spec. You tighten it to a relatively low spec (something like 60 ft lbs) then turn it an additional 140* if memory serves
The last 10-20* of that is an absolute bastard to do. If the shop just hit it with an impact wrench and thought that would do it.. they were obviously mistaken.
New bolt, properly installed, should stay put no problem.
ARP makes a nice crank bolt too. It is torqued to 235 ft*lbs if I remember correctly (w all friction surfaces coated with ARP lube).
You'll need a big torque wrench or pipe for either.
The last 10-20* of that is an absolute bastard to do. If the shop just hit it with an impact wrench and thought that would do it.. they were obviously mistaken.
New bolt, properly installed, should stay put no problem.
ARP makes a nice crank bolt too. It is torqued to 235 ft*lbs if I remember correctly (w all friction surfaces coated with ARP lube).
You'll need a big torque wrench or pipe for either.
Last edited by schpenxel; Dec 7, 2015 at 03:46 PM.
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
The factory bolt isn't supposed to be tightened to a torque spec. You tighten it to a relatively low spec (something like 60 ft lbs) then turn it an additional 140* if memory serves
The last 10-20* of that is an absolute bastard to do. If the shop just hit it with an impact wrench and thought that would do it.. they were obviously mistaken.
New bolt, properly installed, should stay put no problem.
ARP makes a nice crank bolt too. It is torqued to 235 ft*lbs if I remember correctly (w all friction surfaces coated with ARP lube).
You'll need a big torque wrench or pipe for either.
The last 10-20* of that is an absolute bastard to do. If the shop just hit it with an impact wrench and thought that would do it.. they were obviously mistaken.
New bolt, properly installed, should stay put no problem.
ARP makes a nice crank bolt too. It is torqued to 235 ft*lbs if I remember correctly (w all friction surfaces coated with ARP lube).
You'll need a big torque wrench or pipe for either.
This is correct. There is not a final torque setting. Torque to a set number (I cannot recall it either) and then turn turn bolt and additional number of degrees. If the just added Loctite and pulled it tight, they were not even close. It is a bitch to get the bolt turned to the proper degree.
Burning Brakes
Joined: Aug 2014
Posts: 1,240
Likes: 258
From: Tampa FL
GM BOLT, torque to yeild
Crank Bal Bolt - Instal Pass-OLD bolt 330 N·m 240 lb ft Case Extension to Case Bolt (4WD Shipping) 11.2-22.6 N·m 8.3-16.7 lb ft
Crank Bal Bolt - 1st Pass -NEW Bolt for 1st&final pass 50 N·m 37 lb ft Converter Cvr Bolt 10 N·m 89 lb in
Crank Bal Bolt - Final Pass 140 degrees Converter hsng to Case Screw 65.0-75.0 N·m 48-55 lb ft
Crank Bal Bolt - Instal Pass-OLD bolt 330 N·m 240 lb ft Case Extension to Case Bolt (4WD Shipping) 11.2-22.6 N·m 8.3-16.7 lb ft
Crank Bal Bolt - 1st Pass -NEW Bolt for 1st&final pass 50 N·m 37 lb ft Converter Cvr Bolt 10 N·m 89 lb in
Crank Bal Bolt - Final Pass 140 degrees Converter hsng to Case Screw 65.0-75.0 N·m 48-55 lb ft
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
Likes: 0
From: Camarillo CA
Update!!
So, now I'm pissed. The shop said they did everything that we previously discussed in this thread, and after driving it 20 miles it's already starting to make a nasty noise. I can tell it's from the balancer. Time to get a refund and take it to a corvette specialist, which I should've done in the first place. Live and learn I guess...
So, now I'm pissed. The shop said they did everything that we previously discussed in this thread, and after driving it 20 miles it's already starting to make a nasty noise. I can tell it's from the balancer. Time to get a refund and take it to a corvette specialist, which I should've done in the first place. Live and learn I guess...
Racer
Joined: Jun 2013
Posts: 250
Likes: 12
From: Manayunk PA
If this keeps happening... I'd also take it to another shop and ask what the crank snout looks like. Normally only boosted applications that aren't pinned will spin a crank pulley but I have seen shops mess up snouts before from install error.
OP you asked about aftermarket balancers... is there one on the car? I have had one on a customer's car that constantly caused balancer bolts to back out (believe it was a Powerbond). We swapped it back out for a factory balancer and no more problems.
OP you asked about aftermarket balancers... is there one on the car? I have had one on a customer's car that constantly caused balancer bolts to back out (believe it was a Powerbond). We swapped it back out for a factory balancer and no more problems.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 37
Likes: 0
From: Camarillo CA
If this keeps happening... I'd also take it to another shop and ask what the crank snout looks like. Normally only boosted applications that aren't pinned will spin a crank pulley but I have seen shops mess up snouts before from install error.
OP you asked about aftermarket balancers... is there one on the car? I have had one on a customer's car that constantly caused balancer bolts to back out (believe it was a Powerbond). We swapped it back out for a factory balancer and no more problems.
OP you asked about aftermarket balancers... is there one on the car? I have had one on a customer's car that constantly caused balancer bolts to back out (believe it was a Powerbond). We swapped it back out for a factory balancer and no more problems.
Last edited by BadC6; Dec 12, 2015 at 11:26 PM.