LS6 engine vibration in neutral C5Z
05-21-2011, 09:10 AM
#1
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LS6 engine vibration in neutral C5Z
After installing spec 2 clutch/aluminum flywheel I started to get vibration that increased with engine speed while out of gear and car not moving. That engine expired because of another reason but now my new engine is doing same. Anyone have a problem with Spec 2/Al flywheel combo? May not be the clutch but just trying to research before tearing back into the drivetrain.
05-21-2011, 09:17 AM
#2
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Was the clutch / flywheel / pressure plate assembly zero balanced prior to installation ? Sounds like you have one or several components that are out of balance. Is the harmonic balancer in good shape, can you see any wobble at all on it ?
05-21-2011, 09:22 AM
#3
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Actually, the oem spec aftermarket replacement balancer just came apart last outing. I then installed an ATI but still have the vibration. The clutch kit was supposed to be balanced AFIK.
05-21-2011, 09:41 AM
#4
Team Owner
Supposedly, some LS6's used flywheel weighting to balance the engine and were not zero balanced from the factory, but based on the fact that you've had two different engines do the same thing makes is highly unlikely this is your problem. Is the vibration exactly the same with the clutch depressed or released in nuetral? It might be worth a try putting a stock crank pulley on it, but my money is on a balance problem with the flywheel/pressure plate.
05-21-2011, 09:45 AM
#5
Team Owner
05-21-2011, 09:53 AM
#6
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Supposedly, some LS6's used flywheel weighting to balance the engine and were not zero balanced from the factory, but based on the fact that you've had two different engines do the same thing makes is highly unlikely this is your problem. Is the vibration exactly the same with the clutch depressed or released in nuetral? It might be worth a try putting a stock crank pulley on it, but my money is on a balance problem with the flywheel/pressure plate.
05-21-2011, 10:26 AM
#8
Team Owner
05-21-2011, 07:17 PM
#10
Drifting
awhile back i took a new spec 2 and fidanza fly to the machine shop for balancing prior to install. they had to take a shocking amount of material from the pp body to get it zero'd.
i just recently installed a new spec 1 with the very same fly onto a crate LS6. took a chance and skipped the visit to the machine shop. only a couple hundred miles so far but...so far so good.
i just recently installed a new spec 1 with the very same fly onto a crate LS6. took a chance and skipped the visit to the machine shop. only a couple hundred miles so far but...so far so good.
05-21-2011, 07:23 PM
#11
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awhile back i took a new spec 2 and fidanza fly to the machine shop for balancing prior to install. they had to take a shocking amount of material from the pp body to get it zero'd.
i just recently installed a new spec 1 with the very same fly onto a crate LS6. took a chance and skipped the visit to the machine shop. only a couple hundred miles so far but...so far so good.
i just recently installed a new spec 1 with the very same fly onto a crate LS6. took a chance and skipped the visit to the machine shop. only a couple hundred miles so far but...so far so good.
05-22-2011, 08:49 AM
#13
Melting Slicks
If you have time to read a few thousand posts do a search on the
ZERO balancing of these assys.
I can assure you these assys. are NOT ZERO balanced.
Most of the LS engines are externally balanced.
Around 14 grams out of balance seems to be the magic number.
Do you still have the original PP and flywheel ??
As mentioned earlier the clutch is Zero balanced seperate from the PP
and flywheel..................
ZERO balancing of these assys.
I can assure you these assys. are NOT ZERO balanced.
Most of the LS engines are externally balanced.
Around 14 grams out of balance seems to be the magic number.
Do you still have the original PP and flywheel ??
As mentioned earlier the clutch is Zero balanced seperate from the PP
and flywheel..................
05-23-2011, 10:19 AM
#14
Artie,
Food for thought...your car never had that vibration until you solid mounted the engine and the rear diff. The engine mounts have no vibration isolation at all. I use the VBP mounts which are have a layer of Poly in them with no problems. Have Dan check the clutch for sure and have him install his custom motor mounts.
Jerry
Food for thought...your car never had that vibration until you solid mounted the engine and the rear diff. The engine mounts have no vibration isolation at all. I use the VBP mounts which are have a layer of Poly in them with no problems. Have Dan check the clutch for sure and have him install his custom motor mounts.
Jerry
