Ls7 clutch zero balance
Thread Starter
Intermediate
Joined: Jul 2016
Posts: 40
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Ls7 clutch zero balance
Hi guys I read everything I could in the search . Its still not completely clear to me if the ls7 clutch comes both flywheel zero balanced and PP zero balance . I tried finding orientation marks on the new ls7 clutch I received today but could find something defenitive between all the paint marks .
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
WELL<<<<<<<<<<<<<<<<<<<<<<<<<<<< A new GM unit that comes as a complete assembly should be zero balanced.
The problem comes from the actual OEM Factory installed assembly on you C5 may have off set balance pins installed in the outer rim of the flywheel.
It the HOT BALANCE procedure added pins to your flywheel, you will need to TRANSFER those pins to the exact same quadrant that they were on your OEM flywheel and to reinstall that flywheel on to the crank wher it came off to maintain that factory hot balance (MATCH MARK IT)
If you don't have any off set balance pins, you should be good to go.
BC
The problem comes from the actual OEM Factory installed assembly on you C5 may have off set balance pins installed in the outer rim of the flywheel.
It the HOT BALANCE procedure added pins to your flywheel, you will need to TRANSFER those pins to the exact same quadrant that they were on your OEM flywheel and to reinstall that flywheel on to the crank wher it came off to maintain that factory hot balance (MATCH MARK IT)
If you don't have any off set balance pins, you should be good to go.
BC
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
it doesn't matter if it's zero balanced or not because it needs to be match balanced to the original unit by a machine shop anyways. Even if it doesn't have pins, I would still do it just for reassurance.
Thread Starter
Intermediate
Joined: Jul 2016
Posts: 40
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ok I have a big issue then . On the island I live there is not a possibility to do a hot balance . the really small dealer we have here never heard of the hot balance and the car was not bought at the dealer so I don't have there backup .
The car started life as a automatic . the flywheel I found in it has the pin but the car would have vibration at 2000rpm . so I do not want to just transfer the pin . I think this is just going to be trail and error .
The car started life as a automatic . the flywheel I found in it has the pin but the car would have vibration at 2000rpm . so I do not want to just transfer the pin . I think this is just going to be trail and error .
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
if you do not have the original flywheel you will need to do some trial and error. The easiest way to add weights would be to add a washer or two under a pressure plate bolt.
You put a washer under one bolt and note the RPM that the vibration occurs. The better the balance the higher the RPM will get before it starts vibrating. You can also use some vibration analysis apps for your smart phone as the accelerometers typically have a refresh rate of 100HZ which could detect vibrations up to 6000 rpm. Make sure you note the X and Y components of the amplitude because only one of these will not give you the full vibration amplitude. There's always a vector to the vibration, and that will never line up with only x or only y. Pretty simple to calculate if you know Pythagorean theorem. It's just a right triangle where you have the two sides and you calculate the hypotenuse.
You note the amplitude of the vibration and the RPM where it starts. You can plot a graph in excel and interpolate where the washers need to go without putting a washer under every single bolt. You may need to use heavier or lighter washers in addition to adding washers to adjacent pressure plate bolts. It will be a long and tedious process, but you will get there eventually.
You put a washer under one bolt and note the RPM that the vibration occurs. The better the balance the higher the RPM will get before it starts vibrating. You can also use some vibration analysis apps for your smart phone as the accelerometers typically have a refresh rate of 100HZ which could detect vibrations up to 6000 rpm. Make sure you note the X and Y components of the amplitude because only one of these will not give you the full vibration amplitude. There's always a vector to the vibration, and that will never line up with only x or only y. Pretty simple to calculate if you know Pythagorean theorem. It's just a right triangle where you have the two sides and you calculate the hypotenuse.
You note the amplitude of the vibration and the RPM where it starts. You can plot a graph in excel and interpolate where the washers need to go without putting a washer under every single bolt. You may need to use heavier or lighter washers in addition to adding washers to adjacent pressure plate bolts. It will be a long and tedious process, but you will get there eventually.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I helped a froum member in Canada a few years back who replaced the clutch and didn't pay any attention to balance.
We did the washers under the pressure plate bolts and he got it down to NO NOTICEABLE VIBRATIONS!
So, using that method can resolve the issue. I agree that being in your situation, DO NOT use the old weight pins!
There are also vendors who do vibration analysis for a living and can help you fix your vibration issues.. Google for them in your area.
BC
We did the washers under the pressure plate bolts and he got it down to NO NOTICEABLE VIBRATIONS!
So, using that method can resolve the issue. I agree that being in your situation, DO NOT use the old weight pins!
There are also vendors who do vibration analysis for a living and can help you fix your vibration issues.. Google for them in your area.
BC
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Here's a GOOGLE example of a search for CT =
http://www.thomasnet.com/connecticut...4863505-1.html
BC
http://www.thomasnet.com/connecticut...4863505-1.html
BC
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
LOL!!! I installed a SPEC Twin Disk Clutch and I was worried to death that I was going to have a vibration issue. SO,,,,,,,,,,,,,,,, I put the back of the engine on a stand and cranked it up with just the new flywheel to see if I had any weird vibrations from the just the new SPEC Flywheel that I had matched off set balanced to my old C5 ZO6 flywheel with off set balance pins.
SUCCESS!!!!!!! NO VIBRATIONS!
Heres a crappy video that was taken at 10:00 PM (Yea, the neighbors LOVED ME!)
OPEN HEADERS and YES,,, it was VERY LOUD.. Sounded like HEAVEN to me!!!
Just CLICK on the picture to play the VID
SUCCESS!!!!!!! NO VIBRATIONS!
Heres a crappy video that was taken at 10:00 PM (Yea, the neighbors LOVED ME!)
OPEN HEADERS and YES,,, it was VERY LOUD.. Sounded like HEAVEN to me!!!
Just CLICK on the picture to play the VID
Last edited by Bill Curlee; Jul 20, 2016 at 03:37 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Last edited by Bill Curlee; Jul 20, 2016 at 03:43 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Racer
Joined: Jan 2010
Posts: 296
Likes: 33
From: Virginia Beach VA
Any weights in that flywheel HAVE NOTHING TO DO WITH YOUR ENGINE. They were installed while final balancing the engine from which it came. Your engine was not final fine tune balanced.
The best thing you can do is have your new clutch assembly balanced as close to zero balanced as possible then install. If you feel vibrations, which you MAY, then you can do the iterative washer installation exercise that SaberD explained.
Any weights you find in that old flywheel are MEANINGLESS with regard to YOUR engine.
Good luck
Thread Starter
Intermediate
Joined: Jul 2016
Posts: 40
Likes: 1
Hi guys . a small update . I have about 50miles now on the clutch and it feels awesome . no vibration . very smooth engagement . really like the clutch so far .
Installation was not so bad . just alot of work
I could not have done it in one time if it were not for all of your help .
thank you
Installation was not so bad . just alot of work
I could not have done it in one time if it were not for all of your help .
thank you
