while driving the car yesteray i noticed that the AC stopped blowing cold air then some vibrations made me pull over. The AC belt blew. well after using a knife to cut the remaining belt, i drove stright to the local auto parts store. well on the way home about 20 mins after the belt blew the motor started to make noises and after i popped the hood i saw that the belt(alt,pwr string, ect) had come off. well to make a long story short: the harmonic balancer pully was hanging off. at first i thought that the hub of the crank was broken off but after an inspection the bolt in the center of the harmonic balancer was loose and not even connected to the crank. What could have caused this??? im a fairly new LS6 owner and not to familiar with them(used to own a LT1) the car has heads&cam and about all the other goodies, the car recently dynoed 453RWHP on stock bottem end, i hope this is not the problem? please help me!

 

oh yeah i for got to ask: do you have to remove the rack and pinion steering to replace the harmonic balancer??????

 

It sounds like the person that put the cam in did not torque the balancer bolt to the right spec, the damper needs to be completed seated and then the bolt torqued to 37 lb ft and then rotated and additional (I can't remember the exact amount) approx 135 degrees.

The rack and pinion does need to be removed in order to access and tighten the bolt, it's not as hard as it looks and doesn't need to come all the way out of the car, plus you'll need to get a new bolt as the balancer bolt is a one time use only.

 

 

with runamuk. I have heard of these coming off, not only on modded cars, but stockers as well. I don't like the non-keyed, tty method they used for the pulley. If I were you, I'd get a pinning kit and put two pins in it while it's open and being repaired.

Btw, the torque sequence is 240 ft. lbs. with the old bolt, install the new bolt to 37 ft. lbs. and then torque to 140 degrees.

 

This has happened to me several times. The damper is just pressed on, no key. Then there is a bolt on the crank. There is a rather large tolerance for the pressed on damper, and it your on the big end of the tolerance (like mine) it can work it's way off. I've been told the only way to really fix the problem is to replace the damper (hopefully with a tighter tolerance) and make sure the bolt is torqued properly.

 

Correct. The tolerance is .094"-.0176" once the 240 ft.lb torqueing is done. That tolerance defines the distance the face of the pulley the bolt flange pushes on to the end of the crank snout. Mine was at .125" when I did my UD pulley install during h/c.

A buddy recently reinstalled his stock pulley and it walked off shortly after. He said it went on very easily compared to a new one. I've noticed aluminum shavings from the press fit the UD pulleys have when you press them on. That indicates a very tight press fit. If the ID of a stock pulley has been "relaxed" on it's first install and is subsequently reinstalled, I think that's an invite for the pulley to walk off. I think a new pulley should be used if you have to pull the old one. Or, at least pin it to make it a bit less likely to walk.

Most people ignore the manual's listing of the positional tolerance of the pulley install but it's a good indicator as to how loose the fit is if you don't have a set of calipers to measure the diameters with. The further it goes on after the 240 ft.lb. torqueing, the looser the fit probably is.

 

I just went through the process of pinning the crank. I did not have to remove the rack out of the car. I will say you must remove all the lines to the rack and push the rack to the side. I will try to post pics of my install. I did use a pinning kit that included the tool with a new GM bolt.
Mike

 

Thanks guy's , i would love to see the pics of the pin install, im open for more suggestions. thanks again!

 

ttt

 

Here some pics of me moving the Rack to the side and out od the way of the Balancer. As you can see the rack is not out of the car, but all lines and tie rods are disconnected. The bolt on the drivers side Subframe needs to be losend till you see threads. Then use a pry bar to wedge in there and pry down. Leave prybar in position. This will give enough clearance. The first pic shows the rack out of the way of the balancer. The second pic shows the hole I drilled into the crank and with using a provided tool which acts as a JIG to drill perfectly. The second pic.

RACK MOVED


DRILL HOLE


ENGINE AREA



I am here to answer more questions. I did come to the forum myself to ask some of my own. Just returning the favor.

Mike

 

I helped with an ATI Procharger install where we pinned the crank. Very easy as long as you have the rack out of the way. We didn't pull it all the way out - just moved it to the passenger side, partially out the wheel well. We didn't mess with the subframe though.

 

To really help you guys out I will give you the Magnuson install instructions. This will give you step by step instructions on how to remove the rack. Remember you can do this without the full removal of the rack. You only need to drop the Drivers side sub frame bolt down till you see threads. DO not take the nut off of the subframe bolt. These instructions will give you an idea. Oh yea Magnuson recommends 2 pins where ATI uses one. Just click the link below to download.
Pin the crank install

 

The link isn't working. Can you correct it?

Thanks.

 

eric try pm'ing lotus77777. he's the one who orginally posted the pics

 

i found a working link::: http://www.magnacharger.com/pdf/manual04.pdf

 

This is pretty common to spin the pulley off. If you have access to a crank pinning kit do it. I know Andy at A&A corvette rents one for cheap. One more thing that really sucks is oil leaking out of the seal that got messed up when the pulley came off. If you dont change it and it leaks you have to do all that B.S. for the steering over again. Trust me I m waiting for winter to do mine!