Whats the correct answer on balance of LS7 FW when installing a LS7 clutch in a C5Z?
07-09-2010, 12:29 AM
#1
Melting Slicks
Thread Starter
Whats the correct answer on balance of LS7 FW when installing a LS7 clutch in a C5Z?
Im starting to do my LS7 clutch job just before I install my RPM trans. I have done tons of searching the threads. Just dont know what I should do. My 2003 Z06 factory flywheel has 2 slugs inserted for balance. Now do I remove these and transfer to the LS7 FW in the same spots ?? Or install the LS7 clutch/ FW outta the box and see if I have any vibration. Since I can mark the spot on the new FW where the slugs should go if I need to transfer them to the new FW. Not sure here. Thanks!
Last edited by REDZED2; 07-09-2010 at 12:32 AM.
07-09-2010, 12:41 AM
#2
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St. Jude Donor '09-'10-'11
Im starting to do my LS7 clutch job just before I install my RPM trans. I have done tons of searching the threads. Just dont know what I should do. My 2003 Z06 factory flywheel has 2 slugs inserted for balance. Now do I remove these and transfer to the LS7 FW in the same spots ?? Or install the LS7 clutch/ FW outta the box and see if I have any vibration. Since I can mark the spot on the new FW where the slugs should go if I need to transfer them to the new FW. Not sure here. Thanks!
07-09-2010, 12:50 AM
#3
Melting Slicks
Thread Starter
Hey thanks for your quick reply! What will hold the weights in the new FW holes? Or do they go in very tight? A dab of silicone?
07-09-2010, 01:08 AM
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St. Jude Donor '09-'10-'11
07-09-2010, 01:20 AM
#5
Melting Slicks
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The pins have a raised areas that hold them in place. I balance engines on a regular bases. The pins can be put in and out a few times without any fear of them coming out. If you like, you could put a little of the blue Loctite on them before installing. I would not use silicone.
07-09-2010, 01:06 PM
#6
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I had a stock LS6 cutch installed in my '01 and also had a zero balanced aluminum flywheel installed.
Vibrated.
My stock flywheel that was in the dumpster had weights on it from the factory in the form of dowel pins. Normally you would just swap them over but the shop resurfaced the stock fw and put it all together.
Smooth as glass.
I suggest talking to the shop that's going to be doing the install labor, or if it's a garage project, I recommend making friends with your local machine shop staff and ask them. That way you have someone to go back to if you have any issues.
Vibrated.
My stock flywheel that was in the dumpster had weights on it from the factory in the form of dowel pins. Normally you would just swap them over but the shop resurfaced the stock fw and put it all together.
Smooth as glass.
I suggest talking to the shop that's going to be doing the install labor, or if it's a garage project, I recommend making friends with your local machine shop staff and ask them. That way you have someone to go back to if you have any issues.
07-09-2010, 01:42 PM
#7
Melting Slicks
Thread Starter
I had a stock LS6 cutch installed in my '01 and also had a zero balanced aluminum flywheel installed.
Vibrated.
My stock flywheel that was in the dumpster had weights on it from the factory in the form of dowel pins. Normally you would just swap them over but the shop resurfaced the stock fw and put it all together.
Smooth as glass.
I suggest talking to the shop that's going to be doing the install labor, or if it's a garage project, I recommend making friends with your local machine shop staff and ask them. That way you have someone to go back to if you have any issues.
Vibrated.
My stock flywheel that was in the dumpster had weights on it from the factory in the form of dowel pins. Normally you would just swap them over but the shop resurfaced the stock fw and put it all together.
Smooth as glass.
I suggest talking to the shop that's going to be doing the install labor, or if it's a garage project, I recommend making friends with your local machine shop staff and ask them. That way you have someone to go back to if you have any issues.
Im doing the clutch and trans swap myself. Dont have time for stuff like that. Either put the pins in or install out of the box. The service manuals seem to say install out of the box. A lot of people have. I have already put the pins in the same location on the new LS7 FW. I dunno everybody has an opinion on this and it I will most likely leave my FW inspection cover off till I know if theres any vibration or not. IT seems this whole thing is hyped a bit too much.
07-09-2010, 01:49 PM
#8
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^ most cars wont vibrate, but some do...
ALL LS1/6/2/3/7 are fired at the factory and balanced using those dowels if needed.
A machine shop can put the same "imbalance" level into the new flywheel/clutch package. You'll just have to wait a few days with your car apart while they do their stuff.. that's the only way you know it's correct. Otherwise it's a gamble. Do you like dice?
ALL LS1/6/2/3/7 are fired at the factory and balanced using those dowels if needed.
A machine shop can put the same "imbalance" level into the new flywheel/clutch package. You'll just have to wait a few days with your car apart while they do their stuff.. that's the only way you know it's correct. Otherwise it's a gamble. Do you like dice?
07-09-2010, 01:56 PM
#9
Drifting
I had an LS7 Clutch and FW recently installed in my 03Z06 and the shop just installed it out of the box. I did get some slight vibration
The shop said that they always just slap the new factory clutches in w/o re-balancing. They are a reputable Vette shop in my area too. I spoke with another independant vette mechanic that I have had do some performance installs for me and he also just installs them right from the box.
They're supposed to be Zero balanced from the factory
I just have to live with it because I'm not paying another grand for R&R
The shop said that they always just slap the new factory clutches in w/o re-balancing. They are a reputable Vette shop in my area too. I spoke with another independant vette mechanic that I have had do some performance installs for me and he also just installs them right from the box. They're supposed to be Zero balanced from the factory
I just have to live with it because I'm not paying another grand for R&R
07-09-2010, 02:29 PM
#10
Melting Slicks
Thread Starter
^ most cars wont vibrate, but some do...
ALL LS1/6/2/3/7 are fired at the factory and balanced using those dowels if needed.
A machine shop can put the same "imbalance" level into the new flywheel/clutch package. You'll just have to wait a few days with your car apart while they do their stuff.. that's the only way you know it's correct. Otherwise it's a gamble. Do you like dice?
ALL LS1/6/2/3/7 are fired at the factory and balanced using those dowels if needed.
A machine shop can put the same "imbalance" level into the new flywheel/clutch package. You'll just have to wait a few days with your car apart while they do their stuff.. that's the only way you know it's correct. Otherwise it's a gamble. Do you like dice?
07-09-2010, 02:44 PM
#11
Tech Contributor
I had an LS7 Clutch and FW recently installed in my 03Z06 and the shop just installed it out of the box. I did get some slight vibration The shop said that they always just slap the new factory clutches in w/o re-balancing. They are a reputable Vette shop in my area too. I spoke with another independant vette mechanic that I have had do some performance installs for me and he also just installs them right from the box.
They're supposed to be Zero balanced from the factory I just have to live with it because I'm not paying another grand for R&R
The shop said that they always just slap the new factory clutches in w/o re-balancing. They are a reputable Vette shop in my area too. I spoke with another independant vette mechanic that I have had do some performance installs for me and he also just installs them right from the box. They're supposed to be Zero balanced from the factory
I just have to live with it because I'm not paying another grand for R&RVibration due to a balance issue can cause damage, and it may be some time before is surfaces...depending on how you drive the car.
07-09-2010, 04:23 PM
#12
Le Mans Master
I have my clutch assembly in the trunk of my DD from my '01 Z06 and will be dropping it off at the clutch shop for a balance check. It has two very distinct vibration cycles (underload or not) that I am just sick of having to feel and deal with. I fear it will cause internal bearing damage if allowed to continue. First cycle is 1650-1900 RPM with the second cycle occuring at 3400-3900 RPM. I don't spend enough time at the next cycle point to figure out if it will vibrate there too but assume that it will when in gear.
I had a sticky clutch issue way back when during the extended warranty period of the car (10K). Bitched enough to my service manager to get the clutch assembly replaced under warranty because of the low miles. At that point I thought I started to detect a very very subtle vibration that just wasn't there before. I was told it was normal.
Fast forward another year or so and the engine has to come out of the car (13K). I look at the stock PP and demand it be replaced and once again it is replaced under warranty. Vibration still there and gets a little bit worse (very very subtle).
Car goes out of warranty and I decide to take matters into my own hands and bought yet another clutch kit from a fellow forum member that was/is lightly used. That is the vibration stage I am at now. Can't stand it any longer and have the whole rear sitting on the garage floor as I type this.
I looked at both GM flywheels and one has weights and the other does not. However both flywheels have several lightening holes drilled into them but on opposite sides of the wheel. However, the PP and clutch disk are a Centerforce DF unit and the old is the crappy GM clutch by LUK.
I had considered just buying the LS7 kit but after inspecting the DF clutch it barely shows any wear. So one last attempt at a balancing.
Also, the clutch can be balanced on the car by a shop that has the tool and knowledge to do it using a strobe. But not possible when you have LG headers on.
I had a sticky clutch issue way back when during the extended warranty period of the car (10K). Bitched enough to my service manager to get the clutch assembly replaced under warranty because of the low miles. At that point I thought I started to detect a very very subtle vibration that just wasn't there before. I was told it was normal.
Fast forward another year or so and the engine has to come out of the car (13K). I look at the stock PP and demand it be replaced and once again it is replaced under warranty. Vibration still there and gets a little bit worse (very very subtle).
Car goes out of warranty and I decide to take matters into my own hands and bought yet another clutch kit from a fellow forum member that was/is lightly used. That is the vibration stage I am at now. Can't stand it any longer and have the whole rear sitting on the garage floor as I type this.
I looked at both GM flywheels and one has weights and the other does not. However both flywheels have several lightening holes drilled into them but on opposite sides of the wheel. However, the PP and clutch disk are a Centerforce DF unit and the old is the crappy GM clutch by LUK.
I had considered just buying the LS7 kit but after inspecting the DF clutch it barely shows any wear. So one last attempt at a balancing.
Also, the clutch can be balanced on the car by a shop that has the tool and knowledge to do it using a strobe. But not possible when you have LG headers on.
07-09-2010, 05:34 PM
#13
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Mine had a slight vibration below 2k rpm and would come back stronger at about 5,800 through maybe 6100....
Not anymore though with with original weighted wheel back in place.
Not anymore though with with original weighted wheel back in place.
07-09-2010, 11:39 PM
#14
Melting Slicks
Thread Starter
According to c4c5specialist, the practices they use now, defy and contradict some of the teachings in the GM service manuals. I guess a lot of seasoned master mechanics learn the usual trial and error as you go over the years. I trust his comments and opinions AS factual results and not hearsay. So as about the LS7 FW, the correct practice is to transfer the weight pins to the exact same locations on the LS7 FW. Good enough for me. 
