Well I have had 3 different clutch balances in the car and I finally figured out what the LS1 likes....Here goes:
Clutch Ram 402/6130
Stock Flywheel

Install 1)
Install stock flywheel and pressure plate, flywheel was referenced to crank pressure plate was installed. No change from factory balancing. The car felt good but you could feel a vibration 3500 and 6000. Not much but in the shifter. Pulled the combo out.....

Install 2)
Had the stock flywheel and ram plate MATCHED Balance and referenced to the factory flywheel and stock PP combo. Installed this 12 gram out of balance combo which matched the stock combo and noticed a definite improvement but still a slight vibration at 3500 and 6000. 2 months later the combo comes out for most people it wouldn't be an issue

Install 3)
Had the stock flywheel and ram plate 0 Balanced. The plate has to be in a specific position on the flywheel but you should be able to spin the flywheel anywhere you like. ***NOTE The balancing pin has no effect on anything might as well remove it before balancing *** Fired the car up tonight and cracked the throttle a couple of times and held it at 3000, 6000, 6500 and 7000 and feels butter smooth.

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If your installing a new clutch in your LS1, you need to have the Pressure plate and flywheel 0 balanced and the combo needs to stay in reference to maintain the balance, rotating the plate on the flywheel will kill balance.
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Phillip
BTW it sounds like a monster with the 11.75:1cr and X pipe

 

Great Info.

11.75 = :crazy:

 

11.75...HA wait til I build a real motor not a street motor. :lol:
Phillip

 

11.75 :confused: :confused: :confused: what are you going to run for fuel?

:cool: Great info. Thanks.

I'm pretty well convinced I'm going to have to pull mine and zero balance the assembly. I hate to do it but, to minimize down time I'll probably order another assembly, have it balanced and pull the current assembly, (about 3k miles at this time), and replace. Then have the current assembly balanced and keep it for the next time. With luck and $$'s I'll do headers with this 2nd new clutch.

Live and learn....

:cheers:

 

Right now I am running 26 degrees of timing and 93 octane gas and no knock or timing retard. Once I get back to the dyno I am going to figure out how much timing I can run without pulling timing than move onto higher octane fuel.
Phillip

 

Thanks for trying all the combos and figuring it out for us!

But, I could have sworn someone else reported that a zero balance pressure plate and flywheel assembly still resulted in a vibration. Maybe they lost the reference between the two.

What was the actual balance and at what RPM? I guess I'm asking if it was reported to be zero, what was the resolution of their machine.

Thanks!

 

500 rpm @ .025ounce/inches.
Phillip :confused:

 

Hey Phil,
Haven't talked to you in a while.

I would be careful about adding too much timing on the dyno. You can typically get away with a little more timing on the dyno than you can on the street. Just make sure you check it on the street when you are done.

Good luck. :cheers:

 

Phil,

Many thanks for going through the trouble to do all of this for the benefit of the forum. I'll be sure to keep all of this in mind when I get ready to change my clutch out in the future.

BTW, what allows you to keep the assembly in 0 balance between the shop and getting it back into the car? You mention that if the plate moves, the balance will be shot. Is this something that you just treat real gingerly until you get it back in the car, or is there a way to hold it in its position? My intial guess would be to use a clutch alignment tool, but not having done this before on the C5, I can't picture it in my head. Thanks! :cheers:

 

AllCammed

I believe he means the pressure plate-to-flywheel relationship, which can be retained with a simple chalk mark across the two. He is not talking about the clutch disk, which is always zero balanced in any vehicle. Remember...it engages with the flywheel/PP assembly at any one of 360 possible positions, every time you release the clutch pedal!!

Phil--what did you mean about the balancing pin? You mean the weights that go in the flywheel, or are you talking about an alignment dowel?

 

I have been told that even my newly purchased stock flywheel should be resurfaced before the install of my Cartek clutch. Can anyone explain what might be the reasoning behind this? I bought the new flywheel after reading that resurfacing my original stock flywheel could present problems. Now I should resurface a new one? :confused:

 

Bottom line is " if it rotates........balance it!"

You would be suprised what's NOT zero balanced! I did the same thing before the stroker went in and the PP and flywheel where way out there.

For the $ 50 it cost to have it checked and balanced, it definately helps rule out other areas that can cause vibrations!

Good deal Phil!

 

Damn, I just asked about this in another thread.

So now, if you go with a lighter flywheel, isn't there a possibility of puting the whole assy out of balance if you don't rematch the balance to the originall since the engine is externally balanced?

I'm no balance expert, but it seems to me that if the 2 things taking out the harmonics of an externally balanced engine are the flywheel and the dampner then shouldn't they be put back to the same?

I'm not one to argue with PHil97's empirical evidence, but that doesn't match?

Getting kinda lost here...

 

I have a zero balanced flywheel/pressure plate as well and I have no vibration. Stock I had a slight buzz in my ripper shifter at about 3k rpm and 6k rpm. Since installing the new, zero balanced clutch the buzz is gone. I think that the engine is internally balanced and the weights for the clutch made people assume it was externally balanced. The weights appear to be to compensate for the poorly balanced clutches. My flywheel ended up looking like swiss ceese on one end to get it balanced.

 

No, the LS1 is internally balanced.

I replaced my clutch 2 weeks ago. 0 balanced, better than before.

Also, the damper is not keyed as it should be if balance (position) were critical.

 

I zero balanced my stuff together also. It seemes better now than when it was stock. My factory flywheel was off by a little bit and the pressure plate was way off.

 

The factory tolerances for balancing aren't as tight as a machine shop balancing to race motor specs. 0 balance could be +-10 grams. Where in a machine shop its +-.050
Phillip

 

Factory Service manual says that the dampner is not keyed and that the position of the damper is critical for balance.
I can't find any information in the manuals that tells whether the crank and pistons are balanced or not, but I doubt it.

There are 2 different vibrations that can come from the 1.engine/flywheel assy and 2.the propeller shaft and clutch assy.

The damper/crank/pistons/flywheel are one part.
And since you can effectively disengage the pressure plate/friction disc/driveshaft these are the second part.

Where the vibration comes from dictates which parts need to be balanced.
If the motor section is balanced as an assembly and the pp/friction/driveshaft are all at 0 balance then rebalancing different parts to 0 (or not 0) will give different results.

My problem is that I want to replace the flywheel with a lighter one, which seems to me to make sense to rebalance to the original flywheel's weights.

Guys with strokers/rebuilt motors are going to have different results here than the factory guys because the stroker guys probably had a balance job to take the bottom end to 0 balance like it should be.

 

Here you go. This says it is internally balanced. http://www.corvettemuseum.com/specs/2002/power.shtml
I have a stock internals. I replaced the clutch with a zero balanced one, and my car is smoother than it was when new. It was never bad, it's just better now.

 

So, this is all starting to get clear but where do we stand on moving exsisting weights?