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I had a few questions about each one, like, why is the stock clutch more expensive than the ls7 alternative? I had read that the ls7 clutch is not much more and is worth the money, hence looking into this. I ordered the ls7 clutch kit from tick performance. Later, I discovered the 04-905 clutch. From what I read, people said that they have bolted this clutch kit on with no issues. So, I bought it.
I now have both the LuK 04-905 and the GM ls7 clutch kit. There is no difference. The 04-905 is half the cost of the tick "oem" and they are identical. Same casting numbers, same everything. No difference. So if you are looking for a cheap new ls7 clutch, get the 04-905 off Amazon. I am returning the clutch kit from tick back to tick. I am going to keep the other parts that come with the tick clutch kit.
If you order everything that the tick kit comes with(minus clutch, flywheel) and you buy the 04-905 from Amazon, you're saving close to $300. Well worth it.
Just got my 04-905 in from Amazon. What a heavy box! Didn't have a release bearing in the box. Asked them for one they are sending another whole set, want me to return this one.
Are you going to match balance the FW/PP to the old one? Rebuilding the torque tube?
Just got my 04-905 in from Amazon. What a heavy box! Didn't have a release bearing in the box. Asked them for one they are sending another whole set, want me to return this one.
Are you going to match balance the FW/PP to the old one? Rebuilding the torque tube?
I put new Dorman couplers in the torque tube. And one new bearing cuz it was toast but the others seemed fine.
Didn't know it was supposed to come with a release bearing? Mine didn't either. I'll look into that.
As for force matching, I'm honestly not sure. I'm looking at the two LuK clutch kits here and I don't think I'm going to move the weights for two reasons.
1) the clutch from tick has blue paint on it, and a lot more weights in place, while the clutch off Amazon has green paint and way less weights. I'm going to make a guess that the paint has to do with the amount of weights on the kit. Showing how "off" it is when they first balance it, and then adding weights to balance it out. They wouldn't just throw weights on it for fun.
2) the crankshaft in itself should be balanced on its own. Unless gm balanced the clutch while attached to the flywheel and clutch and everything while bolted to the motor, but how/why? I'm going to bolt it on as is as I believe they are already prebalanced and zero'd out. When you take your car in to get a tire rotation, they balance the wheels and tires off the car to zero out them out. They don't balance them on the car.
If I'm wrong, please someone tell me. I'm just inferring/guessing here. Thanks!
Ya, I just checked and you're right. They are sending me another kit and told me to take the part I need out of the kit and then send that kit back. So we'll see what happens. I don't need it, I'm replacing the entire slave cylinder, but, they screwed it up once shipping it out here, now they've screwed up a second time. I'm going to get what I payed for.
I put new Dorman couplers in the torque tube. And one new bearing cuz it was toast but the others seemed fine.
Didn't know it was supposed to come with a release bearing? Mine didn't either. I'll look into that.
As for force matching, I'm honestly not sure. I'm looking at the two LuK clutch kits here and I don't think I'm going to move the weights for two reasons.
1) the clutch from tick has blue paint on it, and a lot more weights in place, while the clutch off Amazon has green paint and way less weights. I'm going to make a guess that the paint has to do with the amount of weights on the kit. Showing how "off" it is when they first balance it, and then adding weights to balance it out. They wouldn't just throw weights on it for fun.
2) the crankshaft in itself should be balanced on its own. Unless gm balanced the clutch while attached to the flywheel and clutch and everything while bolted to the motor, but how/why? I'm going to bolt it on as is as I believe they are already prebalanced and zero'd out. When you take your car in to get a tire rotation, they balance the wheels and tires off the car to zero out them out. They don't balance them on the car.
If I'm wrong, please someone tell me. I'm just inferring/guessing here. Thanks!
You are right about some parts and wrong about others.
You may have already put in the new clutch by now. If possible, hang on to your factory FW and PP, don't throw them away, until you are happy with the new installation. I'm not going to go into great detail about GM's hot balance procedure. Please do a search if you want to know what they do with manual corvettes.
the short is answer is, yes, GM fine tune balanced the entire engine assembly, with the FW/PP on the engine, and sometimes added balance weights to the FW and/or harmonic damper. The weights you are referring to in your post are on the pressure plate. They are not the weights added by GM during the hot balance.
Hopefully your clutch swap goes smoothly and your end result is vibration free.
You are right about some parts and wrong about others.
You may have already put in the new clutch by now. If possible, hang on to your factory FW and PP, don't throw them away, until you are happy with the new installation. I'm not going to go into great detail about GM's hot balance procedure. Please do a search if you want to know what they do with manual corvettes.
the short is answer is, yes, GM fine tune balanced the entire engine assembly, with the FW/PP on the engine, and sometimes added balance weights to the FW and/or harmonic damper. The weights you are referring to in your post are on the pressure plate. They are not the weights added by GM during the hot balance.
Hopefully your clutch swap goes smoothly and your end result is vibration free.
GM does some really stupid s*** sometimes. Just venting. I will look for that hot balance procedure you're telling me about. Thanks.
GM does some really stupid s*** sometimes. Just venting. I will look for that hot balance procedure you're telling me about. Thanks.
You might not think it's stupid s**t after you see why they did/do it. Yes, still done on current manual vettes, from 1997 all the way to now.
I think the process and reasons are good.
I think the manner in which they chose to deal with the situation when someone wants to change a clutch, or flywheel, is severely lacking.
Maybe they could have tackled the NVH situation differently, but I'm sure economic solutions played a big part.
Anyway, read how much you care to about it. If you want to ask any further questions that pop up from it, I'll be glad to answer what I do know.
The ultimate goal is that you end up with a smooth clutch change. There's lots of ways to make that happen. Some are more labor intensive than others. Some involve more luck than others!
I've done some research, and I'm just wondering if I'm supposed to take all the weights off the pressure plate and then force match, or do I just match it directly up? And since I'm going to a ls7 clutch which is heavier in general, do I need a new harmonic balancer then? Soooo many questions.
I've done some research, and I'm just wondering if I'm supposed to take all the weights off the pressure plate and then force match, or do I just match it directly up? And since I'm going to a ls7 clutch which is heavier in general, do I need a new harmonic balancer then? Soooo many questions.
No, you wouldn't be messing with any weights from the pressure plate at all. Those are used by the pressure plate OEM in balancing their own units, close to zero.
If you were to "transfer" any weights at all, it would be weights from your original flywheel to the new flywheel. However there are several reasons why that is NOT the best method.
You are trying to match the ultimate final balance of your original FW/PP combo to the new FW/PP combo. It would be more work to try to match original FW to new FW AND THEN original PP to new PP. That would work too, but just not necessary.
Here's the first and most important set of questions:
1. Have you already removed your stock FW and PP?
2. Have you already had a new clutch (FW/PP/disc) installed?
3. if no to both above, are you planning on doing the work yourself or having a shop do it?
that will help determine the "best" way to proceed.
the short is answer is, yes, GM fine tune balanced the entire engine assembly, with the FW/PP on the engine, and sometimes added balance weights to the FW and/or harmonic damper.
This is the reason you want to move the balance weights from the old flywheel to the new one. There are many reasons why GM did it this way. One is cost of course. But the end result is a smoother running engine. Swapping over balance weights from the old flywheel isn't too much of a fuss....
Here's the first and most important set of questions:
1. Have you already removed your stock FW and PP?
2. Have you already had a new clutch (FW/PP/disc) installed?
3. if no to both above, are you planning on doing the work yourself or having a shop do it?
To answer your questions:
1) No, I have not
2) No, I do have a LuK ls7 clutch waiting to go in
3) I plan on doing the work myself
To answer your questions:
1) No, I have not
2) No, I do have a LuK ls7 clutch waiting to go in
3) I plan on doing the work myself
This is all of the best scenario to have the best chance of getting it done smoothly. Doing the work yourself and using an OEM (sort of) replacement.
I would suggest that you mark the flywheel orientation to the crankshaft BEFORE you remove it. Most likely, the "7th" holes will be aligned, but it's not always the case. The bolt pattern is an equally spaced symmetrical 6 hole pattern, so you can physically mount the FW in 6 possible orientations to the crankshaft.
If your current FW/PP are the original stock pieces, then they will only bolt together in one orientation with each other, so that's good.
See if you have any balance weights in your stock flywheel. There are 12 equally spaced through holes around the perimeter of your flywheel. If you can see through them, they do not have a weight. If you cannot see through one ore more holes, there are balance weights in them. They were installed by GM during the hot balance process.
Using this picture I got off the internet, are the 12 spaces you're referring to on each side of the pressure plate bolts?
it's hard to see if there are 12 there in this pic, but there are 12 holes, smooth not threaded, and equally spaced, 30 deg apart.
It's easier to see from a plan view, directly above the flywheel, but yes, those are the holes you referenced.
These two describe why transferring weights is not the best method.
Regardless, you would not be messing with any weights on the pressure plate at all, ever.
But to answer the question about installation: the balance weights are small steel slugs, not lead, and have some small "protrusions" on the outer surface of their bodies. They are then pressed in to the receptacle holes flush or slightly countersunk to create a slight interference fit from the deformation of the protrusions. Also an equivalent of blue Loctite is used to help make sure they don't come loose.
They are easy to just punch out if you wanted to try to reuse them or transfer them over.
Just need to decide how you want to proceed from the start.
1. just put in the new clutch as is out of the box and hope for the best. This might work, it might not. There's no way to tell. IF you have vibrations afterwards, take it all apart again and then get the new unit matched balanced to the original unit. Not just the flywheels, not just the pressure plates, but match the new FW/PP combo to the original FW/PP combo.
2. spend the money up front, get the new units matched to the originals, install in the same orientation as stock (because you marked that location before removal!), and that should be that. The problem will be finding a shop that (A) believes it should be done and (B) understands how to match balance. It seems like many shops only know how to ZERO balance components and not MATCH balance components. Its kind of like a cashier not knowing how to give you change when they've already punched it in the computer and you give them extra coins. They can't do the math themselves and can only rely on what the machine tells them to do.
3. install new stuff out of the box and end up with vibrations: Then you could also go through an iterative balancing approach yourself, without having to tear it all apart again. You could use the balance weights taken from the original flywheel, washers under the pressure plate bolts, several different methods to this. It is an iterative process and will take some time. But it is cheaper (free) than getting a shop to match balance for you, and you don't have to waste your time trying to convince the experts why you'd like to do something they are convinced is unnecessary.
There are many solutions. The end goal is getting a vibration free clutch swap.
That's awesome. That's what I needed to hear. Thank you. I will mark it, and take the entire assembly to a shop to have them match it. I don't feel like chancing it. Hopefully it doesn't take very long.
That's awesome. That's what I needed to hear. Thank you. I will mark it, and take the entire assembly to a shop to have them match it. I don't feel like chancing it. Hopefully it doesn't take very long.
I'd call the shops and ask them if they are able to match balance components or assemblies instead of just zeroing them out. I was surprised to hear how many said they were not able to do that or not sure of how to do it. Most machines analyze and read out an imbalance, then tell you where to remove mass and how much to remove in order to get it to zero. So they don't know how to use the analysis to go the other direction and create an imbalance on purpose.
Be prepared for people to tell you it's not necessary or even wrong to do. They will tell you that if you are going to do something, you need to just have them all zero balanced. That's not accurate and won't definitely help. The good thing is it can be relatively simple to correct by yourself after the fact if it all still goes wrong and you end up with a vibration anyway. Since you are comfortable doing the work yourself, it won't be a problem.
If you find a shop that will do it for you, please get some kind of documented printout showing what the end result of both assemblies is after whatever work they do. I have now also seen the results of a very crappy attempt at match balancing, and the printouts showed it.
A balance report should at a minimum show the amount of unbalance and the orientation of that unbalance. Make sure you/they establish datums relative to your original fw/pp combo and its orientation to the crankshaft.
LS engines are an internally balanced design. However, those engines going into manual corvettes are further fine-tune balanced externally to address NVH issues related to vibration paths. This is what the shops usually don't understand or refuse to believe. Even though you can go right to the factory and WATCH the process being done, and ask them why they are doing it.
Well I just got my second 04-905 in from amazon WITHOUT the release bearing. They are giving me one. All suppliers of this set use the same photo showing the RB.
08-19-2017, 07:23 PM
Ls7 Clutch
