Engine rebuild, clutch swap... odd vibration
06-12-2023, 12:48 PM
#41
Racer
I took the flywheel and pressure plate back to be re-balanced. He said it was only 4 ounces out, then I looked and it was clocked differently than the balance marks on the pressure plate. He said that it shouldnt matter but there are balance weights on the pressure plate and it was balanced as an assembly at Mcleod so I would think that would change it.
Then in your initial post...
Then you said you had the clutch out at a machine shop for a balance. I assume this means both the flywheel and PP? They would surely have made it clear that the clocking of the pressure plate was critical.
06-12-2023, 02:45 PM
#43
Racer
So just in case it doesn't, are you / have you been involved in any of the wrench work, or just writing the checks? Not that there's anything wrong with paying a pro, but trying to get a full picture. Sometimes the pros care more about seeing your taillights go over the horizon than doing the job correctly.
Also, are you implying you took it to the same place to check balance a second time?
A few other things to consider - have you checked the runout in the part of the prop shaft that engages the pilot bearing / friction disk? What kind of pilot bushing / bearing are you running, and what does the tip of the prop shaft look like?
Also, are you implying you took it to the same place to check balance a second time?
A few other things to consider - have you checked the runout in the part of the prop shaft that engages the pilot bearing / friction disk? What kind of pilot bushing / bearing are you running, and what does the tip of the prop shaft look like?
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Bill Curlee (06-15-2023)
06-15-2023, 09:34 AM
#44
Melting Slicks
Thread Starter
Yes I do all my wrench work. I have built this car multiple times.
I took it back to the only machine shop in my area that can do it.
I am going to check the prop shaft runout before reinstalling. Do you have a good setup method to do so? I am guessing I need to make some metal backet to hold my gauge for the test.
I took it back to the only machine shop in my area that can do it.
I am going to check the prop shaft runout before reinstalling. Do you have a good setup method to do so? I am guessing I need to make some metal backet to hold my gauge for the test.
06-15-2023, 10:30 AM
#45
Racer
Sorry, no pointers on checking runout. I've done it on my C4's ZF but haven't had the driveline out of my C5 yet. The only reason I'm thinking bent prop shaft is because you say it smooths out above 2500 rpm. Generally a reciprocating assy imbalance will only get more pronounced with rpm.
06-15-2023, 03:58 PM
#46
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St. Jude Donor '08
spfautsch Has some SOUND ADVICE! 
I strongly recommend separating the prop shaft from the TT Housing and checking the rubber couplers and the bearings separately.
RECOMMENDATION: Install the Flywheel/Pressure Plate on the engine and spin it up before you reinstall the bell housing/Drivetrain.
I did that on my 02 ZO6 to insure that there were NOT any strange vibrations after my SPEC Twin Disk Clutch install. Worked like a champ.
NO VIBRATIONS on the ZO6
I strongly recommend separating the prop shaft from the TT Housing and checking the rubber couplers and the bearings separately.
RECOMMENDATION: Install the Flywheel/Pressure Plate on the engine and spin it up before you reinstall the bell housing/Drivetrain.
I did that on my 02 ZO6 to insure that there were NOT any strange vibrations after my SPEC Twin Disk Clutch install. Worked like a champ.
NO VIBRATIONS on the ZO6
06-15-2023, 07:15 PM
#47
Melting Slicks
Thread Starter
spfautsch Has some SOUND ADVICE!
I strongly recommend separating the prop shaft from the TT Housing and checking the rubber couplers and the bearings separately.
RECOMMENDATION: Install the Flywheel/Pressure Plate on the engine and spin it up before you reinstall the bell housing/Drivetrain.
I did that on my 02 ZO6 to insure that there were NOT any strange vibrations after my SPEC Twin Disk Clutch install. Worked like a champ.
NO VIBRATIONS on the ZO6
I strongly recommend separating the prop shaft from the TT Housing and checking the rubber couplers and the bearings separately.
RECOMMENDATION: Install the Flywheel/Pressure Plate on the engine and spin it up before you reinstall the bell housing/Drivetrain.
I did that on my 02 ZO6 to insure that there were NOT any strange vibrations after my SPEC Twin Disk Clutch install. Worked like a champ.
NO VIBRATIONS on the ZO6
06-15-2023, 09:26 PM
#48
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St. Jude Donor '08
IF,, you find out that the vibrations are being caused by prop shaft issues, I strongly recommend replacing the pilot bearing or at least carefully examining it for wear/damage.
Hook the input shaft to a big drill motor and spin it as is and see if it spins smooth/quiet and vibration free.
Hook the input shaft to a big drill motor and spin it as is and see if it spins smooth/quiet and vibration free.
07-07-2023, 05:02 PM
#49
Melting Slicks
Thread Starter
Verdict is in! .030 runout on the torque tube. I went solid front and rear couplers. I am switching to poly from DSS in the front and leaving my solid in the rear and see what I get on my runout then. Hopefully the coupler comes in and I can report back middle of next week with good news!
07-23-2023, 09:42 AM
#50
Melting Slicks
Thread Starter
Well sorry to report that didn't fix the issue. The more I read the more I am starting to think its just the nature of the beast with this RXT clutch. I have read multiple forum posts of people having the same vibration I am having and swapping clutches fixes it. I am going to pull the trans one more time and remove the clutch and start the car to see if the vibration is there to know 100%.