Clutch rattles on Deceleration?

[TS8]

Yes, from what I understand that is what they call chatter/shudder/judder.
My case together with Revvin9k is a loud "RATTLE" letting go off the gas and coast.

[BluEVOIX]

Originally Posted by TS8

Yes, from what I understand that is what they call chatter/shudder/judder.
My case together with Revvin9k is a loud "RATTLE" letting go off the gas and coast.

Thanks for clearing it up for me.

I was researching about clutch chatter etc.. And I found an article that might help:

http://www.turbomagazine.com/tech/04...ics/index.html

T: What causes clutch chatter?
S: A high coefficient of friction, bad motor mounts, an incorrectly machined flywheel or faulty pressure plate, spring-centered race disc (aggravates chatter), and contamination (oil, grease, or rust).

Chatter is basically the engine winding up in the mounts as the clutch is engaging and then bouncing off the mounts, disengaging the clutch for a brief moment before engaging again and winding up again. No matter how aggressive a clutch is that would normally chatter severely on a normal street car, it generally won't chatter at all on a car with solid mounts and a rigid disc because there is no wind-up effect.

Have you guys upgraded your engine mounts? Probably the most effective one would be the front mount since from what I remember its the one that stops the engine roll.

Actually on second thought this would probably help me and those with chatter only from slow moving starts. But not a bad mod to do that might help...

[TS8]

Wow, thanks for the article!
As the article states, chatter happens during engagement.

Since our coasting rattle seems to come from torsional vibration (causing the disk to "play" in the housing), the engine mounts may help.

The 264 cams that I have installed probably contributes to the vibration also.
My Evo is a DD, and at close to 75K miles, front engine mount may be a good upgrade.
This is assuming that the disk "vibration" is causing it.

Do you use a stiffer mount/mounts? what brand?
How is the CCI clutch? Any noise? I was thinking of going with the 3rd stage, but decided to use the Exedy I had on hold for a long time.
Thanks a lot! Toshi

[BluEVOIX]

Originally Posted by TS8

Wow, thanks for the article!
As the article states, chatter happens during engagement.

Since our coasting rattle seems to come from torsional vibration (causing the disk to "play" in the housing), the engine mounts may help.

The 264 cams that I have installed probably contributes to the vibration also.
My Evo is a DD, and at close to 75K miles, front engine mount may be a good upgrade.
This is assuming that the disk "vibration" is causing it.

Do you use a stiffer mount/mounts? what brand?
How is the CCI clutch? Any noise? I was thinking of going with the 3rd stage, but decided to use the Exedy I had on hold for a long time.
Thanks a lot! Toshi

Well the CCI stage 4 is quite good. No noises grabs strong but it chatters. It doesnt make any of those chattering noises, but when on a dead stop and with slow acceleration forward it chatters. So usually I just slip give more gas and raise the rpms higher during the roll before completely engaging the clutch. Well its a ceremic 6 puck so it grabs pretty strong. On the stocker I would actually work the clutch to work smoothly with only 800-1000 rpms but this wone I need a couple more hundred rpms.

My only regret was using the throw out bearing they supplied. So far mine is good but I've read a couple instances where people had theirs fail and I wish I could have used an OEM one as a precaution.

I'm going to get the Blox front engine mount after I pay off some bills and hopefully that helps with chatter and with a different issue. When on high rpms shifting to 5th it does not engage smoothly and rubs a little. But if I double clutch it goes in smooth like butter. So I think I might need the mount to fix this issue because it cant be a syncro issue.

[gsrboi80]

Blox mount does not help the decel. May help your shifting though

[TS8]

Thanks, the mount and/or engine dampener was my next step.
So I guess nothing short of changing out the clutch w/ OEM TOB and flywheel might be the only fix. Thank you for the input!!

[Srt4...]

i have similiar problems with a hd act 2600 and motors mounts... i believe my hks280 cams have something to do with it as well

[TS8]

Srt4, did you use a lighter flywheel with the ACT?

I'm still thinking the lighter flywheels causes the torsional vibration from lack of mass on the outer rim.

I think the cams just makes it even worse at some RPMs.
Thanks.

[TS8]

Anyone else with similar issues?

[skold]

i have an rps 6 puck and it makes all kinda noise and so does the TOB, but i say f it it moves just fine.

[Raceghost]

Hello al,

That vid that some one posted here is spot on the money of what mine has sounded like since I bought it little over a year ago. Mine is on decel in any gear, or some times when I coast in any gear. I have a Stage 2 ACT clutch, w/10lbs. ACT Fly.

I noticed that when I would change fluid in the tranny and center diff on my EVO 8, it would quite down for a while, but then be back.

I also noticed that I am missing the Frost plug on the top of my tranny, I do not have a pic at the moment, but will get one. I Have noticed that the noise occurs more when I have driven through a puddle or street drain dip at the intersections in most streets. hmmmm....is water to play. Is any one else missing there frost plug. One, this will cause the noise to be loud, for it is no longer encased completly in liquid as well as an enclosure, no noise deadening... 2 it might be alowing water to get in with the oil and cause issues that way.

I am not sure, on what or why, but I know my clutch is still holding strong. I hope we can solve this mistery one day?

[BluEVOIX]

Originally Posted by TS8

Srt4, did you use a lighter flywheel with the ACT?

I'm still thinking the lighter flywheels causes the torsional vibration from lack of mass on the outer rim.

I think the cams just makes it even worse at some RPMs.
Thanks.

I have a 10.8 lbs RRE flywheel. So I dont think the flywheel could be causing your issue.

Is it possible that a couple of your flywheel and/or clutch bolts came loose?

[TS8]

I wonder what is actually hitting what to cause the rattle?

[TS8]

Anybody else with the rattle when you let off the gas?!

[revvin9k]

Originally Posted by TS8

I wonder what is actually hitting what to cause the rattle?

This is EXACTLY what I want to figure out.


What ever it is, it has to wear out soon enough. lol