Belt problem gets worse!!!
Thread Starter
Pro
Joined: Nov 2002
Posts: 506
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From: Atlanta Georgia
St. Jude Contributor
Belt problem gets worse!!!
Well the other day I was on the way home and my belt started to come apart. Today I went to the dealership and got a new belt, came home and started to install it. After I finished I cranked the car up and watched the belt for a minute to make sure it stayed aligned. I noticed after about five minutes at idle the belt seemed to slip off the Crankshaft pulley about one grove. I shut the car down and took a look. I think my damn crankshaft pulley is coming off the crankshaft. The bolt must have worked its way loose since my Head and Cam install in April. Oh well I guess this means I have a good excuse to get an underdrive pulley now. Just curious if anyone else had this problem? :banghead: :rant:
Le Mans Master
Joined: Jul 2002
Posts: 7,370
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From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Re: Belt problem gets worse!!! (dave777)
I've seen a couple of posts about this in the past, if you reach down to the crank pulley can you feel if the bolt has backed out? if it has you should replace it with a new one, when these are torques they are stretched enough that they are considered a one time use bolt. :cheers:
Intermediate
Joined: Aug 2002
Posts: 38
Likes: 0
From: Rhome Texas
Re: Belt problem gets worse!!! (dave777)
Dave,
I have encountered the very same problem with regard to your accessory drive belt. My harmonic balancer came loose during dyno pulls after an egine rebuild. Upon further investigation, it was found that the harmonic balancer bolt was not torqued properly! GM states, that the harmonic balancer bolt should be torqued to a value of 245 foot pounds utilizing the old bolt to properly seat the balancer into position onto the crankshaft; The harmonic balancer bolt is good for one use only... torque to yield. Once this has been accomplished, remove the existing bolt and discard it. Reinstall the new bolt and torque it to a value of 37 foot pounds with a final pass at 140 dergree's torque to yield.
At present, I have had no further issues with regard to my balancer.
Regards... :seeya
I have encountered the very same problem with regard to your accessory drive belt. My harmonic balancer came loose during dyno pulls after an egine rebuild. Upon further investigation, it was found that the harmonic balancer bolt was not torqued properly! GM states, that the harmonic balancer bolt should be torqued to a value of 245 foot pounds utilizing the old bolt to properly seat the balancer into position onto the crankshaft; The harmonic balancer bolt is good for one use only... torque to yield. Once this has been accomplished, remove the existing bolt and discard it. Reinstall the new bolt and torque it to a value of 37 foot pounds with a final pass at 140 dergree's torque to yield.
At present, I have had no further issues with regard to my balancer.
Regards... :seeya
Safety Car
Joined: May 2003
Posts: 3,814
Likes: 105
From: Dearborn Heights Michigan
Re: Belt problem gets worse!!! (Patrick Di Credico)
Had the same problem with my 2000 Cpe. Threw a belt at drags and discovered crank pulley bolt all the way out and pulley had worked its way about 1/2" forward. Suspect head & cam installer didn't torque properly. New pulley, belts, bolt cost over $700, Ouch!
Fred K.
Fred K.
Safety Car
Joined: Feb 2002
Posts: 4,942
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From: Gaffney, S.C.
Re: Belt problem gets worse!!! (dave777)
According to the Chevy Service Manual the balancer should be marked to it's original position on the crank and if replaced the balancing weights transfered to the new balancer. It does not tell how to tell where to place it if it falls off with no prior placement markings :crazy:
Thread Starter
Pro
Joined: Nov 2002
Posts: 506
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From: Atlanta Georgia
St. Jude Contributor
Re: Belt problem gets worse!!! (irfgt)
Yeah, it has not came off, yet. I hope that it does not. I did mark it when I took it off for my cam install, and put it back to where it was. I think that the pulley/balancer is one of the worst designs of the LSX1/6 engines. I should be keyed and also have a way to use a conventional puller on it. I guess chevy thought that it would nevrer need to come off huh? Oh well I guess I will be taking it in next week for a underdrive pulley, maybe this way I can atleast rest better knowing that that factory POS is gone. Hey, and maybe I can even pick up a few HP.
Team Owner
Joined: Mar 1999
Posts: 28,753
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From: San Jose/Bear Valley CA
CA Events Coordinator
Re: Belt problem gets worse!!! (dave777)
I have seen this happen a bunch of times... Hopefully the crank is still in good shape. Pin or key your next one in place and I hope it stays on this time!! :)
VR :cheers:
VR :cheers:
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Thread Starter
Pro
Joined: Nov 2002
Posts: 506
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From: Atlanta Georgia
St. Jude Contributor
Re: Belt problem gets worse!!! (vetterdstr)
Well it is confirmed. I found out earlier that my crankshaft pulley bolt had pulled out. The shop said that they were able to just take the bolt out by HAND!!! That is not good :eek: Oh well I now have a new underdrive pulley, new belts and a new ARP bolt (which is now loctited in). Maybe I even picked up a couple of HP, who knows.
Pro
Joined: Apr 2002
Posts: 726
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From: Denver CO
Re: Belt problem gets worse!!! (dave777)
The early post about replacing the bolt makes perfect sense. The threads and the bolt shank "stretch" when torqued and have a certain amount of "spring." This spring holds the bolt in tension. After a bolt is torqued once, the stretch has "hardened" the bolt steel. It won't hold the same spring as original, at the specified torque. LockTite might work, but the best solution is to pay a few bucks and replace the bolt. This is a detail often overlooked by mechanics in many areas of the engine. There are many bolts that require replacement before reassembly. I learned the hard way; threw a rod at 90 MPH in an MG Midget :mad (supposed to put in new rod bolts :bb ) (was winning against that Prelude until then :lol: )
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My 2cents worth
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Glad those low income days are behind me :D
My 2cents worth
:cheers: