I'm having a hard time finding someone in my area to balance my new clutch. I'm going with the LS7 clutch/pp and a Fidanza lightweight flywheel. Is it totally neccasary to balance? Supposedly they are zero balanced from the factory. Thanks for the help.

 

Have you tried a machine shop? Where are you located, best to fill in your information as someone local might be able to point you in the right direction.

 

Sorry, filled it out. I'm in Jacksonville, Florida. I've called about 3 machine shops so far, no luck.

 

Bullet, you might do some reading here in the forum about the clutch/flywheel balancing scenario.
Some of the early C5's (my 2000 was one) were balanced ON THE FLYWHEEL using small press-in lead weights in the flywheel holes.
I don't know if they stopped doing this on the later years.
As a result, if you removed the stock flywheel and put on a perfectly balanced replacement, the engine might vibrate (a lot!!!).
This happened to me, and it was a disaster.
2 months in the shop, the dealer pulled the clutch 5 times trying to figure it out.

There are three ways to approach this:

1. Ignore it and hope for the best. It seems many guys have, and been lucky. Apparantly most of the engines were not externally balanced.
I don't recommend this method - see above. Thank God it was a warranty issue.

2. Know how your original flywheel was "clocked" on the crank. There is no dowel pin on the crank like the old days, so the flywheel can go on 6different ways. Then find the lead weights (if there are any) and put them on the new flywheel in the same "clocked" position as the old flywheel. This is real; it is all explained in my 2000 service manual.

But, the aftermarket flywheel may not have holes located properly to switch the weights. Then, proceed to option 3.

2.Balance check the old flywheel/clutch combo, and see if it is out of balance. If it is, then "unbalance" the new combo to the same extent. Then mount the new flywheel in the same "clocked" position on the crank as the old one came off.

Serious stuff!
Definitely worth your time to do a search herein and see if this process could apply to your '04.

DG

 

Thanks for the help. I did a search, half of the posts didn't work. So take the old assembly and balance it and make the new assembly out of balance by the same amount? What a pain in the ****!

 

okay I also have your exact same set up. They say that since the aluminum flywheel is cnc machined it should be perfect. : The problem with balancing clutches like the other guy talked about in a previous post is that at the factory they are balanced with a designated flywheel. So since you have a different flywheel you will most likely benefit from balancing. it is required NO. Will you fell a vibration? that is hit or miss. I balanced the flywheel first, by drilling some material off of the back side of it. Once that was perfetly balanced then we bolted the pressure plate to it with out the disc. Because there is no possible way to line up the disc perfectly and it is not heavy enough or in a spot to cause a vibration so you do not have to worry about balancing the disc. For the pressure plate we spun it up on the balancer and used clay as weights. Once it was balaced we measured the weight of the clay and made a chunk of metal the exact same weight and tig welded it in the right spot to the pressure plate. The we engraved a line in both the pp and fw so that during install it would be lined up correctly. You could do this with those rivet weights I just didnt have any, you would also have to get lucky with were you needed weight because those holes are not perfectly around the entire pressure plate. Overall my the ls7 w/fiudanza alum flywheel was 7lbs lighter than the stock set up and with the balancing the car spins up much faster with zero vibration. I had it done at my friends local machine shop for 100$ He would do it for you but you would have to ship it of course and it probably wouldnt be worth it since I know you should be able to find a shop around you to do it. FYI my clutch assembly is balanced for 15,000 RPM

 

This thread worries me a little. I jsut got a fidanza flywheel, and was gonna get the Centerforce 12" DF clutch, and had no intention of getting it balanced, as I have never had to do it before on other cars.

Jason

 

Well, I don't want to be a wet blanket. But the very last thing you want to do is spend a week installing a new clutch, then have it vibrate.
Guys herein that do a lot of clutches should be able to add valuable advice; but this issue definitely bit me on my brand new 2000.

The way I learned about this issue was when my new 2000 had a little vibration in the clutch pedal as it was being released. But otherwise, it was smooth. I complained to the dealer, and they decided to install a new flywheel/clutch combo. They removed and tossed the original, 1000-mile unit, and popped in a new combo. The engine vibrated like a buzz saw at 4000 rpm. It was very noticeable, and unacceptable.
They went back in and installed another combo, still vibrated. So, while I was preparing my Lemon-law paper work, I read my new service manual, and found all the info about the flywheel balancing on the manual tranny cars. The dealer techs had never heard of this! At that time, they had probably never changed a C5 clutch.
So, they called Bowling Green for instructions, and were informed that if they had pulled the OEM flywheel off and not checked for weights, then there was no way to know what/where the weights should go; except to use a special external strobe balancing machine, which they didn't have.
Finally, a factory service rep came down to Dallas with the strobe equipment, and worked on the car until he got the weights in the right place. All told, they pulled the driveline down 5 times.
Now, it's pretty smooth, but not as good as it was when new; and the little vibration when releasing the clutch is still there - turns out this is kinda normal, most of the ones I have driven since then do this a little.

Absolutely the worst horror story I have ever had with a car; it was 3 months old, and spent 5 weeks in the shop.
If I ever have to change a clutch, I think I'll just sell it!

Good luck!
DG

 

Sorry, just doesn't make sense to me. If the flywheel is balanced, it's balanced. If it needs weight to compensate for an engine imbalance there is not much of a way to figure that out short of rebalancing the engine assembly. What about people that use different crank pulleys/harmonic balancers? Would that not cause a vibration if the engine is not truly internally balanced? Ican understand if the flywheel/pressure plate is not zero balanced, but other than that, don't see how it could cause a problem. I'm gonna verify it's zero balanced and then let it rip.

 

Sounds like they are not made as zero balance at the factory, so they have to compensate. I'll take mine to the local machinist and have it balanced as a set to be safe (Fidanza and centerforce).

 

Im putting an LS6 setup in mine now, I took my new and old clutch Flywheel to the Orielly Auto Machine shop here to get it balanced, Not to bad of a job pulling the drivetrain but I really didnt want to tear it back apart for a vibration problem.

 

Silver bullet, I can understand your apprehension; historically all Chevy smallblocks except the 400, were fully balanced internally.

But, this is a paraphrase of what the factory rep who fixed my car said:

"The lS1 engines are assembled to be in-balance internally.
However, they discovered that some of the engines could exhibit vibration without further fine balancing.
Only the manual transmission setups seemed prone to this noticeable vibration, so none of the units mated to auto trannies were final-balanced".

"If an engine was spun up, and exhibited enough unbalance, and if it was designated for a manual-tranny install; the engine was fine-balanced by installing small lead weights into holes in the flywheel and the harmonic balancer, as required".

I am looking at pages 3-115 thru 3-118 of my 2000 GM service manual, which explains the flywheel balance weights, and how to mark, remove, replace them onto the new flywheel or harmonic balancer in the same relative position as they were in originally.

Hmmmm; maybe what they do is just assemble engines without bothering to balance individual rotating assemblies.
Then, during the run-in process (where they spin each engine on a big
lathe-type machine) they check for balance. When they find one out a bit, they just pound weights into the flywheel and balancer.

I would bet that the big majority of engines are not out enough to notice, so most clutch/flywheel replacements work just fine.
But I was the unlucky stiff who had the bad one.
So, my advice is for those who don't feel lucky (to quote Dirty Harry).

When you pull the OEM flywheel, mark the original bolt "clock" position relative to the crank flange.
Examine the holes in the flywheel for pressed-in lead plugs.
If you don't find any lead, don't worry, be happy.

If you find lead, you will know that the OEM wheel has been intentionally unbalanced to offset a small internal engine imbalance, and you will need to replicate that imbalance to avoid possible vibration after assembly of the new pieces. The service manual deals with OEM replacements, so they instruct you on how to just switch over the lead weights to the same location in the new FW. In an aftermarket FW, you will need to be a bit more creative.

Oh, this whole process is also designated for the balancer replacement, as mentioned above. I had no weights in my balancer - whew.

Cheers,
DG

 

Ashley, good deal.
But be sure, if they find an imbalance in the OEM and match it with the new unit, that you put the new unit back on the crank in the same "clocked" position as the old one. These flywheels have no locating dowel, so they can go on in 6 different locations.
If you add weight to the new unit, then bolt it on differently from the old unit, you will be doubling your imbalance issue, rather than eliminating it. In other words, if your OEM FW had a weight in the 6 o'clock position, you need to add the weight to the new fW in the same 6 o'clock position on the crank.

If you already pulled the old fW off, and did not mark its position on the crank, you may can still find where it was by looking for a mark left by the 7th hole in the FW. This hole does not have a bolt in it, and may leave a little rust impression where it was seated.

Guys, I wish you the best on all this. I'm harping on it so hard cause I don't want any of my Vette brothers to go through what I did.

DG

 

I replaced my balanced already, and that did not add any vibrations, so hopefully I will not have imbalance problems with the flywheel.

Jason

 

I plan to install a 12" centerforce clutch and pressure plate. If I mark the flywheel and just have it re-surface will it need to be balance?

 

I sure wouldn't think it would get much out of balance with just a re-surface. Just mark it's location as you said, and bolt it back in the same location. I hear a lot about changing both the FW & clutch as a combo, but I don't have any first-hand info on what would be wrong with re-using a good flywheel. I know GM sells the FW/clutch as one unit, but that's just marketing overkill probably.

DG

 

I did the same thing and I would recommend against it. I had my stock flywheel resurfaced, and installed a Centerforce 12"... now I have vibration over 2k RPM. It's not bad, but I know it's there. As luck would have it, I just recently ran into the "stuck in 4th gear" problem, so the tranny is coming back out anyway... time for new clutch & flywheel. I'm happy with the Centerforce clutch... just should have sprung for a new flywheel and had everything balanced the first time.

 

Thanks for all the help. After numerous calls to machine shops with no luck, I finally found one that does flywheel/press. plate balancing and seems to be knowledgable. Clutch will be on the ground tomorrow, and everything back together including LG Streets by this weekend. Again, appreciate the advise, without this forum, I'd probably have a vibration and be one pissed off puppy!

 

FYI the shop here calls itself a 'Brake Shop' not necessarily a machine shop.

 

Stock short block, match balance the new flywheel and P/P to the old stock units.

New aftermarket short block, then have the new flywheel and P/P zero balanced.

Simple as pie.