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Username Post: Clutch chatter        (Topic#347177)
Dynamutt 
Forum Newbie
Posts: 95

Reg: 08-03-15
09-17-17 07:35 AM - Post#2707899    

Installed Chevy 502 crate motor awhile back. I installed new fly wheel, pilot bearing, clutch, pressure plate, throw out bearing, clutch fork. It chatters up shifting and down shifting. Pulled it apart and replaced clutch and pressure plate, throw out bearing, with a different brand. It still chatters, no change. What the hell? When I installed the pilot bearing I drove it in flush, could it be in to far allowing the shaft to move? I just don't get it. Any help would be appreciated. Thanks



 




grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
09-17-17 08:25 AM - Post#2707904    
    In response to Dynamutt

since youve already replaced the clutch disc and pressure plate, I'd point out that,
many times clutch chatter is the result of an un-even flywheel surface, any decent machine shop can surface grind the existing friction surface a few thousands to correct that issue.
clutch chatter is the result of un-evenly applied clamping surfaces, usually a high spot(S) on the clutch pressure plate its housing or the flywheel surface, , but heat warping or a broken spring or mis-aligned spring will also cause this symptom.



http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
Dynamutt 
Forum Newbie
Posts: 95

Reg: 08-03-15
09-17-17 09:16 AM - Post#2707908    
    In response to grumpyvette

I agree, but it's a brand new Gm flywheel for this engine.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
09-17-17 09:41 AM - Post#2707910    
    In response to Dynamutt

you'll want to verify the flywheels mounted so its not wobbling, it may be warped, or the crank flange its mounted too has been bent or theres debris between the flywheel and crank flange, you,ll want too use a dial indicator mounted on the block and rotate the flywheel to find out, if the flywheel friction surface or outer diameter ,changes its distance from the block as it rotates

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
Dynamutt 
Forum Newbie
Posts: 95

Reg: 08-03-15
09-17-17 10:12 AM - Post#2707914    
    In response to grumpyvette

If it wasn't mounted straight or if there was some sort of wobble or deflection wouldn't there be a lot or some kind of vibration at slow or high speed? There seems to be zero vibration at any speed. Don't want to seem like I'm arguing with you just don't want to do any unessasary tear down or machine work. I do appreciate your comments and will look into it. Thanks



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17142
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
09-17-17 11:28 AM - Post#2707920    
    In response to Dynamutt

I'm certainly not suggesting this is the only potential cause, but if the flywheel was balanced and centered, its rotational mass would not be an issue even if it was a few thousands out of true or warped, , it would not tend to vibrate running, but it would provide an un-even clamp force during clutch engagement

the link I posted has sub links with a great deal more info

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 09-17-17 12:04 PM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 3288

Reg: 04-15-05
09-18-17 08:22 AM - Post#2708002    
    In response to Dynamutt

One area that can cause issues like chatter is the interface between the pilot bushing and input shaft pilot stub on the front of the input shaft.

If you have an inspection cover on the bottom of the bell housing that will let yu get to the clutch assembly, pull it off, have an assistant push the clutch pedal in, and hold it there, while someone literally tries to move the driven disk up and down. There shouldn't be much movement at all, only a thousandth or so.

Another thing to look at is input shaft end play. Of course, the trans needs to be out of the vehicle to do so, but, check two ways, front to back input shaft movement, shouldn't be a lot, no more than .005 or so, and, input shaft up/down, left/right. Too much, transmission main shaft to input shaft clearance is excessive, needs to be reset tighter.

Along with the last thing above, also check the front drive shaft yoke in the tail housing to yoke, shouldn't be any movement up/down, left/right.

Too much of any of all that can help cause clutch chatter/erratic engagement.

Just another couple of things to check and discount.



 
raycow 
Honored Member
Posts: 27353
raycow
Loc: San Francisco, CA
Reg: 11-26-02
09-18-17 12:29 PM - Post#2708037    
    In response to Dynamutt

One possible cause I haven't seen mentioned yet is bad engine mounts. If they are soft, broken, or loose, they can allow the engine to move as you engage the clutch, and that movement can interact with the clutch linkage to cause chatter.

Ray

Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.


 
IgnitionMan 
Valued Contributor
Posts: 3288

Reg: 04-15-05
09-19-17 02:52 AM - Post#2708097    
    In response to raycow

Good info on the engine mounts, Ray.



 
Trucked_up 
Valued Contributor
Posts: 4948

Loc: 315 er
Reg: 03-23-02
09-26-17 07:26 AM - Post#2708885    
    In response to IgnitionMan

I have had bellhousing misalignment on several Chevys...Used the offset dowels to correct it so the tranny input shaft is centered on the pilot bushing..




 
bowtie44s 
Valued Contributor
Posts: 3867
bowtie44s
Age: 35
Loc: wv
Reg: 08-29-12
09-26-17 09:16 AM - Post#2708895    
    In response to Trucked_up

  • Trucked_up Said:
I have had bellhousing misalignment on several Chevys...Used the offset dowels to correct it so the tranny input shaft is centered on the pilot bushing..




Just wondering, how did you discover that? You can't see the pilot bearing with the clutch on. Did you measure or bolt them up with the clutch out?

Jeff

'88 Chevy K3500, aluminum head roller cam 511inĀ³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 




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