Harmonic Balancer Problem
Thread Starter
Instructor
Joined: Jul 2008
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Harmonic Balancer Problem
I had an ac belt snap a few days ago... Just realized the bolt backed out on my balancer and that caused it. It came out about 1/4 an inch, Is there any tricks to getting that bolt to stay in. I just replaced the bolt after doing my motor work 
Melting Slicks
Joined: Feb 2001
Posts: 2,791
Likes: 355
From: Northville, MI
You have two ways to go...the NEW GM bolt or a hardened APR or equivalent bolt. The GM bolt is a torque to yield bolt, the procedure is to torque it to 37 ft-lb and then tun the bolt another 140 deg. With the GM method NEVER reuse an old bolt other than to seat a balancer. Best way is to get a torque multiplier tool and lock the flywheel, and add a little extra locktite for insurance. The APR bolt method only requires torque to 250 ft-lbs, as I recall.
Tech Contributor
Joined: Jan 2007
Posts: 19,245
Likes: 1,092
From: Dyer, IN
How did you do it with the cam change? How did you install the balancer, what bolt, and what torque.
Thread Starter
Instructor
Joined: Jul 2008
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I bought a brand new GM bold and used the stock balancer. Didn't torq it down to spec I guess. I think we only did 40 ft lb. I've been told its 175 ft lb fro ma few Vette guys in my town. I installed it by hitting it on w a rubber mallot and small piece of 2x4. Then tigthened bolt till it was snug and torqued it down.
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
No where near tight enough. Here's the procedure. Note that the torque value is 37 lb-ft to seat the new bolt, actual bolt preload is through a measured rotation. Anyone telling you to use a torque value doesn't understand the installation procedure.
Tech Contributor
Joined: Jan 2007
Posts: 19,245
Likes: 1,092
From: Dyer, IN
I bought a brand new GM bold and used the stock balancer. Didn't torq it down to spec I guess. I think we only did 40 ft lb. I've been told its 175 ft lb fro ma few Vette guys in my town. I installed it by hitting it on w a rubber mallot and small piece of 2x4. Then tigthened bolt till it was snug and torqued it down.
So you installed the balancer with a mallet and a 2 x 4, and torqued the bolt to 40 ft lbs?
Sorry partner....you got what you deserved......silly....
