"Chirping" Lq9 - Need advice
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"Chirping" Lq9 - Need advice I've got a drive belt "chirping" issue with my LQ9. I've been fighting belt "chirp" for a while, and I suspect that the issue is with my power steering pulley, but I'm not sure..
I've painted all of the drive pulleys, and originally I thought that was it, but before I removed all of the paint I tried buying a new belt (dayco)..The problem went away for a while, but came back quickly.
Due to an interference between the power steering gearbox and the p/s pulley, I had to use a smaller diameter ford pulley instead of the original. There is a design difference between the original pulley and the Ford in the length of the pulley nose. The Ford nose is shorter than the GM one, and due to clearnces between the pulley edge and one of the P/S pump mounting bolts I can't press the pulley to the same depth of the original pulley (unless I remove one of the three P/S pump mounting bolts)
So I do have pulley mis-alignment. But I did measure all of the pulley alignments in comparison to the crankshaft hub (tensioner, alternator and P/S) and I noticed the following:
Tensioner: 0mm diff.
P/S: 1.32 mm diff
Alt: 0.98 mm diff
Is 1+ mm enough to cause belt squeal? Should I try a better belt 1st?
The squeal does go away when the belt/pulleys warm up in 60 deg plus weather. When it's colder the squeal never goes away so there is a temp. factor involved -- Does that indicate anything?
Any help would certainly be appreciated!
I've painted all of the drive pulleys, and originally I thought that was it, but before I removed all of the paint I tried buying a new belt (dayco)..The problem went away for a while, but came back quickly.
Due to an interference between the power steering gearbox and the p/s pulley, I had to use a smaller diameter ford pulley instead of the original. There is a design difference between the original pulley and the Ford in the length of the pulley nose. The Ford nose is shorter than the GM one, and due to clearnces between the pulley edge and one of the P/S pump mounting bolts I can't press the pulley to the same depth of the original pulley (unless I remove one of the three P/S pump mounting bolts)
So I do have pulley mis-alignment. But I did measure all of the pulley alignments in comparison to the crankshaft hub (tensioner, alternator and P/S) and I noticed the following:
Tensioner: 0mm diff.
P/S: 1.32 mm diff
Alt: 0.98 mm diff
Is 1+ mm enough to cause belt squeal? Should I try a better belt 1st?
The squeal does go away when the belt/pulleys warm up in 60 deg plus weather. When it's colder the squeal never goes away so there is a temp. factor involved -- Does that indicate anything?
Any help would certainly be appreciated!
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I went to a single-belt system using S&P's "low PASS mount" A/C kit on an otherwise stock Corvette front drive setup. With that as the only change, my belt kept squealing, making rubber dust, and bouncing off the A/C pulley when the A/C was engaged. I ended up replacing the factory tensioner with a solid adjustable unit and that stopped the problem. Given this, I'd say any changes to factory belt drive could result in your problem.
I went to a single-belt system using S&P's "low PASS mount" A/C kit on an otherwise stock Corvette front drive setup. With that as the only change, my belt kept squealing, making rubber dust, and bouncing off the A/C pulley when the A/C was engaged. I ended up replacing the factory tensioner with a solid adjustable unit and that stopped the problem. Given this, I'd say any changes to factory belt drive could result in your problem.
I can't remember who sells the adjustable tensioners on here but LS1Nova71 made a topic about one and the link or name of the sponsor was in it. Option 2 is commandeer one from a Japanese car in the JYD if you're feeling creative.
Last edited by gofastwclass; Nov 26, 2010 at 07:49 AM.
I had belt "squeel", the belt was actually slipping on the pulley, and the Katech solid tensioner took care of that problem, but if you're only having a "chirp" I would recommend trying a Gaterback belt, they tend to take care of that problem. I've seen bone stock cars, Jeep Cherokees for instance where the Gaterback belt is the only way to keep the annoying chirp away. Any new belt would cure it for a while, but it would always return with a regular belt.
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if you're really close and the bolt is the only thing in the way is a bolt....shave it a little. 1mm is not very much. take the bolt off and grind the head down 1mm or so.
or, you can get an under/over driven pulley that's smaller in diameter. and use a similar to stock one.
or, you can get an under/over driven pulley that's smaller in diameter. and use a similar to stock one.
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[QUOTE=gofastwclass;14165800]No, my home built accessory drive is off more than that. You are using a shorter belt... right?
Yes, I experimented with different belt lengths until the tensioner was mid-range in it's travel after the initial belt stretch.
[previous post] I had belt "squeel", the belt was actually slipping on the pulley, and the Katech solid tensioner took care of that problem, but if you're only having a "chirp" I would recommend trying a Gaterback belt, they tend to take care of that problem. I've seen bone stock cars, Jeep Cherokees for instance where the Gaterback belt is the only way to keep the annoying chirp away. Any new belt would cure it for a while, but it would always return with a regular belt.
I have heard good things about the gatorback belts, that may be the trick. I did try manually applying more tension and the issue did not go away..It sounds like the belt may be the trick?
Yes, I experimented with different belt lengths until the tensioner was mid-range in it's travel after the initial belt stretch.
[previous post] I had belt "squeel", the belt was actually slipping on the pulley, and the Katech solid tensioner took care of that problem, but if you're only having a "chirp" I would recommend trying a Gaterback belt, they tend to take care of that problem. I've seen bone stock cars, Jeep Cherokees for instance where the Gaterback belt is the only way to keep the annoying chirp away. Any new belt would cure it for a while, but it would always return with a regular belt.
I have heard good things about the gatorback belts, that may be the trick. I did try manually applying more tension and the issue did not go away..It sounds like the belt may be the trick?
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Verdad Gallardo To make sure it's a belt and not a bearing in a pulley or something, take a bar of soap and hold it to the underside of the belt with the engine idling (DO BE CAREFUL THOUGH), the noise will go away if it's the belt, and sometimes will be quiet for a day or so.
