Vibration in shifter

Porch made an interesting comment in another forum.

https://944hybrids.forumotion.com/t2054-x-member-bolts-working-loose#23166

Perhaps you should check your subframe clearance (again?) and see if anything has settled enough to be making contact between engine and frame.

Rich

Thanks, I have checked clearance everywhere and nothing is touching. If I get enough motivation I will check the motor mounts this weekend.

Well, so far everything has checked out fine. I had the car dyno-tuned today and the vibration is still there. Looks like I will be pulling the clutch out, again.

Arthropraxis wrote:Well, so far everything has checked out fine. I had the car dyno-tuned today and the vibration is still there. Looks like I will be pulling the clutch out, again.

Sux, man. If it's any consolation, so am I. I'm still getting major chatter in the clutch, so I'll be going Spec stage I, and my TT bearings are so loud it's hard to hear the radio.

I am going with a LS7 setup and a 11in Sachs friction disc part #BBD4163. I have the Spec clutch pack now and would reinstall it but I am trying to minimize the downtime. Before taking the Spec set out, the LS7 set is going to get match balanced to the original FW/PP in an effort to get rid of this vibration.

Some of these flywheels had weights added to them to balance the motor. If the original flywheel was 0 balanced then you can replace it with another 0 balanced FW. If the original FW is not 0 balanced the new FW will have to be matched to it. That info would have been good to know when I last removed the clutch to check for balance.

Arthropraxis wrote:I am going with a LS7 setup and a 11in Sachs friction disc part #BBD4163. I have the Spec clutch pack now and would reinstall it but I am trying to minimize the downtime. Before taking the Spec set out, the LS7 set is going to get match balanced to the original FW/PP in an effort to get rid of this vibration.

Some of these flywheels had weights added to them to balance the motor. If the original flywheel was 0 balanced then you can replace it with another 0 balanced FW. If the original FW is not 0 balanced the new FW will have to be matched to it. That info would have been good to know when I last removed the clutch to check for balance.

What is the process to make the FW to be match balanced to the engine after the fact?

iow, if the original FW had weights added to it to balance an out-of-balance engine at the factory, and you don't have that original FW to show you the weights, how can you get a new FW balanced to the out-of-balance engine?

Arthro, where are you hearing about the engines being unbalanced from the factory? I'm not saying it isn't possible, just sounds like someone's theory on an internet forum and I would be really surprised if that was the case. I have the same engine as you (04 GTO) and not having any of these issues. I'm using a stock Luk replacement flywheel, Centerforce CF360010 pressure plate, and TPC conversion disc which I had to grind the flange down on. And I didn't even have the assembly balanced.. no vibration.

supes6 wrote:Arthro, where are you hearing about the engines being unbalanced from the factory? I'm not saying it isn't possible, just sounds like someone's theory on an internet forum and I would be really surprised if that was the case. I have the same engine as you (04 GTO) and not having any of these issues. I'm using a stock Luk replacement flywheel, Centerforce CF360010 pressure plate, and TPC conversion disc which I had to grind the flange down on. And I didn't even have the assembly balanced.. no vibration.

Search for hot balancing or match balancing on the Corvette forums there are lots of posts about this issue.
Acorad, hot balancing is where the FW is balanced on the car. Some of the Corvette techs do this procedure. If your flywheel is already 0 balanced and you don't have the original FW that may be an option.

Fixed! I just finished putting in a LS7 clutch with a sachs disc. I thought I had transmission problems because it was hard to shift but it must have been the clutch dragging. Now it shifts like butter. The pedal is lighter and it doesn't chatter on engagement.
I sent the clutch back once and the manufacturer said everything was fine and to look elsewhere for the problem. I am going to be selling the Spec FW disc and PP it has about 2000 miles on it, I suggest you get it balance prior to installation.

Arthropraxis wrote:Fixed! I just finished putting in a LS7 clutch with a sachs disc. I thought I had transmission problems because it was hard to shift but it must have been the clutch dragging. Now it shifts like butter. The pedal is lighter and it doesn't chatter on engagement.
I sent the clutch back once and the manufacturer said everything was fine and to look elsewhere for the problem. I am going to be selling the Spec FW disc and PP it has about 2000 miles on it, I suggest you get it balance prior to installation.

Arthro, I just read through your post carefully because I'm experiencing the exact same problem. Just to confirm, it sounds like you solved your problem by doing away with the Spec clutch entirely and replacing it with a LS7 clutch and Sachs disk? So are you saying the Spec clutch was inherently bad no matter how much balancing was done to it? It sounds like you had the LS7/Sachs setup match balanced before installation. I can't do this with my application because my engine came out of an automatic. I'm wondering what the best way forward for me is. Thanks!