Question, Ive been doing alot of searching here and have been unclear on something- the flywheel, is it actually balanced to the motor? All my last cars it was not but I"m reading conflicting reports on the flywheel here. Also, what about an automatic, dont the autos use a driveplate? It would seem silly for the flywheel to be balanced to the motor...

I bought a LUK Pro Gold Stage 2 clutch kit with disc, plate and flywheel and am not sure how it is "balanced". Guess I'll call Tom at Carolina Clutch tomorow to find out. Last thing I need is to put it in and have a huge vibration.

 

You will need to have the new flywheel ballanced to the OE unit. Or you will have vibration problems. If your engine was zero ballanced... then you could install your new zero ballanced flywheel and all would be ok.

VR

 

I bought my LUK stage II from carolin clutch.... it had a slight vibe when installed and now it slips at every shift over 5000 rpms. Make sure the self adjuster for the pressure plate is fully adjsuted. This is not part of any normal install instrucions nor are there anything more than torque specs in the box.

Some people on here say teh flywheel is balanced to the motor, but that'd be dumb... all the big tuners (A&A, Lingenfelter, LGM, Cartek) told me the motors are "supposed" to be a zero balanced assyembly, but in some cases GM does't do the best job.

My stock flywheel had two small counterweights in it, but this was to balance that assyembly. If you verify your new clutch/flwyeel to be zero balanced, then you ahve a vib you have a warranty claim w/ GM. My tech called their head tech line a few times and their fix for a vibing clutch is to just order an complete new assy. The lates instructions state to transfer none of the balance weights b/c the motor is supposed to be a balanced assy and the flywheel/clutch is supposed to be balanced.

All that said, all the tuners told me they never trust any clutch mfg and test balance all of them.

Good luck it's been a real PITA for me w/ noresolution as of yet.

 

Ohh ok I gotcha... so in a nutshell, just make sure that the clutch and P plate are balanced to each other by going to a machine shop and having that verified?

Why does your clutch slip? Eh oh, this is scaring me. And what sort of adjustment is this? Dont the LUK clutches have a 12k mile, 12 month warranty?

Dang I love this forum. So much knowledge and experience floating around.

 

Yes... call Mark at MSI (forum vendor on the left) and he'll explain the adjustment. The clutch is slipping beacuse my pressure plate isn't providing full clamping force. It's easier to push in than my stock clutch and it's not supposed to be

 

This is by far the worst clutch job ever. My project is progressing very slowly cause I sprained my butt and its hard for me to lie down under the car. THat and it doenst help I get home in the evening and by the time I take care of other things the auto parts stores are closed. To rebuild my tranny I need a rather large gear puller and I just ran out of time last night.


OK new question- how "in balance" are LS1's in general? My car has always had a little bit of shake but I'm not sure if it was a cylinder misfire, or just the nature of the motor.

 

I am also having issues with the balance on the LUK. It is frustrating to say the least. I heard a bad batch went out that were not properly balanced. The car is driveable but very annoying. On high rpm shifts/downshifts, there is severe vibration that makes it feel as if the driveshaft is about to snap.

I have very low pedal effort just like cobra4b does, however I do not have the slipping problem.

 

I'm going to disagree with just zero balancing it and elaborate on what vetterdstr said, and this is just based on my research and couple LS1 clutch jobs.

The OEM flywheel and pressure plate are zero balanced from the factory. This is accomplished via putting weights in the holes that can be seen around the perimeter of the pressure plate.

The caveat to this is if the motor is slightly imbalanced. While the LS1 is "internally balanced", all this really means is that there are no big counter weights on the harmonic balancer or flywheel (like on a small block 400). On earlier LS1's weights were added to the flywheel to account for imbalances in the motor. Proof of this is the service manual procedure for replacing the flywheel; one of the steps is to transfer the weights from the original to the new. This is only mentioned in the flywheel replacement section, not the clutch replacement section which is misleading.

IMO you should always replace the flywheel when doing a clutch job. This is because taking material off the surface of the flywheel puts the pressure plate fingers farther away from the throw out/slave and would require shimming the slave to bring it closer to the pressure plate.

Having said that, the new flywheel and pressure plate should be spun at an automotive balancing shop and zero balanced as a unit as is said in the above posts. Even if the vendor says that their part (pressure plate and/or flywheel) is zero balanced, they should be spun as a unit and more than likely will need some balancing.

Now the kicker is that if you have weights on your original flywheel they need to be transferred to the new one in the same location. Note that the flywheel can go on different ways but there is an ofset hole in the crank and flywheel to line it up right. This is essentially taking the clutch assembly out of balance but it is done to make up for imbalances in the motor. Either this or spin balance your current non-vibrating flywheel and pressure plate and have the new assembly balanced to whatever the original was found to be (as vetterdstr said).

I used to be an advocate of just zero balancing the PP and FW but I have seen way too many posts of people who have done that and still had vibrations.

I have no inside contacts at GM, these are just my observations after reading many many LS1 clutch posts. My flywheel did not have any weights attached so I did not need to transfer any. With any luck, you will not have any weights on your flywheel and not have to worry about it.

 

Whats confusing about this?
Do it once and do it right and you will always be able to sleep at night.
Unless you have had a complete balance job done on your motor it will not be a zero balance flywheel unless they added the pins to the harmonic balancer.
Sure some of you have zero balanced your flywheel and PP and got away with it, but I would bet if you checked your rotating mass it's out of balance. Your just to numb to feel it.

 

[QUOTE=corvettebob1]Whats confusing about this? QUOTE]


Confusing cause I wasnt clear if the flywheel (if there was weights on it) was balancing the flywheel itself or was actually balancing the motor. In that case, I wasnt sure when replacing the flywheel if it should be "rebalanced" to the old flywheel, or if it should be just left alone. But the question was answered.

Of course I havent pulled the flywheel yet. That will be tonight's project...cross my fingers that there are no weights on it and I'll still get the flywheel checked out.

 

I've been told by the big tuners that the counter weights in my stock flywheel are to zero balance the assyembly. The latest GM manual specifically states not to transfer the weights.

In the engine balancing section it says...

Engine Flywheel

Important

The flywheel, clutch, and pressure plate are a balanced assembly and are not available as individual components. The pressure plate mounts or locates onto the flywheel via two dowl pins in the flywheel. In the pressure plate is not alligned properly onto the dowel pins and tightened down, the pins may bend and the plate may be incorrectly positioned which will effect component balance.

*New flywheel, clutch, and pressure plate assembly onto and existing engine: Do not transfer or install balance weights.

**** This was printed out in front of my own eyes by the GM tech who did my work. He even check the flywheel replacement part. The newest manuals state not the transfer anything.

HOWEVER, they do talk about transfering weights when removing or replacing the crankshaft balancer.

 

I think it is zero balanced.

I installed a Ram VDS with a new aluminum flywheel. No weights were transferred as there is no place to put them. No vibration and clamps great.

 

From my personal "files"

I have put a zero ballanced clutch assembly on my first LS1 engine and it vibrated like a **** at 4,000 rpm's. Had I balanced it with the old flywheel I would not have had that problem. I had to pay to remove it and do it again the right way.

My next engine was zero ballanced and we were able to install a zero ballanced flywheel and clutch assembly and this by far runs the best without any vibrations from idle to redline ALL DAY!!

So by sharing my "expensive" experiences with you... I hope that whatever you do, you get your flywheel and engine ballanced to your satisfaction without any vibration. Many of us here have given you the info you need to do it the right way. So it is up to each individual to do what they think is right...

VR

 

Does it not make sense that if your current FW and PP are out 10 grams (very noticable) at the 2-o-clock position and you have no vibration that the new FW and PP should be balanced the same way?

It may be that they used to put weights on the flywheel and then switched to putting the weights on the balancer or whatever. The above should be followed to ensure no vibration when replacing the FW, PP or both on any vehicle.

The only way to tell whether the weights are for the clutch or the engine would be for someone with weights on their flywheel to have their current, non-vibrating FW and PP spun and see if it's balanced or out of balance due to the weights.

I know it seems like overkill, and why it seems so much more important on an LS motor than on others I don't know, but if you are doing the clutch on your C5 yourself you don't want to have to do it again anytime soon.

 

If you can feel it that badly stop driving the car. A bad enough enough vibration could cause you to destroy or start the destruction of a bearing assembly.

I had to have my motor rebuilt this year and the mechanic told me he thought the motor was oil staved at some point causing a rod bearing to get damaged eventually burning up and coming apart. I told him to the best of my knowledge that had never happened however I had a badly balanced P.O.S. Spec clutch in there for about 12 days before swapping it out. The mechanic said that certainly could have started the process of a bearing going bad and it just progressed from there.

 

I just got my Luk Pro Gold, get it neutral balanced! Mine was out! I sent it to my machine shop and he spun it up to neutral balance it,he removed some weight from the flwheel to get it to "zero" .

 

Can some one with the service manual verify this??? If it is correct this is VERY important info.....

 

This brings up an interesting point. I have a 98, which is undoubtedly an "earlier" LS1. As for the part that says do not transfer the weights, this is off of a newer service manual.

In this case (I'm still at work), I'm crossing fingers that both my flywheels are already zero balanced, but in any case I will mark the position of the old flywheel (and p plate) now, and then take both assemblys to a machine shop. I will then see if the old unit is "balanced" and if the new unit is "balanced". And then, get the new one balanced to the old ones spec and reinstall that to the same position. Darn these fine details hehe.

Sorry Im rambling I'm still at work so I've been thinking about this all day. I can see why a small weight difference would cause a bad vibration with the flywheel of a LS1 relatively large compared to the other cars i've been used to. Wow I am sure learning alot though.

 

I just called TJ in Roswell and spoke with their senior Corvette tech. His version was to absolutely transfer the weights from the old fly wheel to the new one. My situation was that I replaced my old clutch system with one of the new ZO6 kits sold by Fred Bean, I replaced the slave cylinder also.

I did reference where my factory flywheel was and placed the weights (2) in the same location as they had been to the new flywheel...

Any more opinions???

 

The thing I hate about this is that I cannot get a 100% definate answer from anyone. The top tuners say one thing, my GM tech says another. Is there any way we can get a 100% answer to this... anyone know Dave Hill's number?

I still have my stock clutch assyembly, but I'm not sure how I'll know which way it was oreinted on the crank? I think the tech said the 7th hole on teh flywheel is ligned up with the hole on the crank shaft. I'm going to have to do the same thing vetrdstr did... pull it out and have it re-balanced and adjusted. My vibration is very minor and has decreased since i put it in, but the PP isn't adjusted and it won't hold a shift over 5500 rpms.


ericdwong... make sure you call Mark at MSI to speak with him about the pressure plate adjustment.