VIBRATION AFTER INSTALLING NEW CLUTCH

dirtyred11

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Ok guys, finished up installing my clutch 2night and I go to crank it for the first time and I feel this vibration through the car. I try and give it a second to smooth out and hope its nothing major, so I take it out for a test drive and didn't even go a block because I was scared of the vibration. It got worse in some parts of the rpm's and then smoothed out some in other rpm's. I did use a new tob, pilot bearing, new flywheel but the shop brought me a 10.5' six bolt instead of the 11'' I had and I just used a 10.5' clutch but I used some bolts I bought at Ace because I couldn't find the bolts or I had different ones or whatever. But anyway, my question is what do you guys think is going on???? and it does vibrate in neutral, I even reved it a little and it got worse.... Thanks in advance for all the help
 

RichV

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If the issue is not a misfire, something is wrong with the balance.

What exactly was installed? Why would you use a different flywheel than stock?
 

dirtyred11

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If the issue is not a misfire, something is wrong with the balance.

What exactly was installed? Why would you use a different flywheel than stock?
I ordered another stock flywheel from a local auto parts store and they brought me a 6 bolt flywheel but my original one was a 11'' and the one they brought me was a 10.5' and the first clutch I ordered fit it so I went on and used it. My clutch bolts were also different so I went to Ace and bought some more and put some locktight on them. I also installed a new pilot bearing and throw out bearing, and torqued and greased everything. So im wondering why its vibrating so bad....
 

RichV

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I don't understand what you mean 10.5" and 11", isn't that a different clutch? I've never seen a flywheel that is not 6 bolt.

Can someone answer if you can put a Fox 5.0 flywheel on a 4.6? Fox flywheels are 10.5".
 

Win

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I don't understand what you mean 10.5" and 11", isn't that a different clutch? I've never seen a flywheel that is not 6 bolt.

Can someone answer if you can put a Fox 5.0 flywheel on a 4.6? Fox flywheels are 10.5".


I think he is meaning he has a 6 bolt GT flywheell. To my knowledge non pi motors have a 6 bolt and I think some pi have them too but there are also 8 bolt flywheels on some of them. I know the 96+ cobra has a 8 bolt.

OP technically the 11" flywheel and 10.5" disc should work just fine.

but why couldn't get get you a 11" clutch kit??

Im im thinking he gave you a improperly balanced flywheel. Or maybe you knocked a weight loose off your DS or maybe don't have some bolts fully tightened.

I would check every bolt first and if that doesn't fix it. The clutch kit or flywheel they supplied to you is the issue.
 

dirtyred11

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I think he is meaning he has a 6 bolt GT flywheell. To my knowledge non pi motors have a 6 bolt and I think some pi have them too but there are also 8 bolt flywheels on some of them. I know the 96+ cobra has a 8 bolt.

OP technically the 11" flywheel and 10.5" disc should work just fine.

but why couldn't get get you a 11" clutch kit??

Im im thinking he gave you a improperly balanced flywheel. Or maybe you knocked a weight loose off your DS or maybe don't have some bolts fully tightened.

I would check every bolt first and if that doesn't fix it. The clutch kit or flywheel they supplied to you is the issue.
I called and got the place I got the flywheel from to order me another one, and when I was referring to the 10.5' and 11'' flywheel I guess I should have been saying yes that was the clutch sizes but on the original flywheel that came off the car the 10.5' clutch was to small so I ordered a 11'' clutch but when they brought me my new flywheel the 11'' clutch was to big on this new flywheel which told me that the 10.5' clutch fit it which meant that this new flywheel had to be smaller than the original. I don't actually know the size of the flywheels but that's how I came to my conclusion on the sizes.
 

Win

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I called and got the place I got the flywheel from to order me another one, and when I was referring to the 10.5' and 11'' flywheel I guess I should have been saying yes that was the clutch sizes but on the original flywheel that came off the car the 10.5' clutch was to small so I ordered a 11'' clutch but when they brought me my new flywheel the 11'' clutch was to big on this new flywheel which told me that the 10.5' clutch fit it which meant that this new flywheel had to be smaller than the original. I don't actually know the size of the flywheels but that's how I came to my conclusion on the sizes.

When you say didn't fit specify what you mean. All your going to see is the teeth on the flywheel once the clutch us on.
 

RichV

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Also, one other thing I forgot to mention. Flywheel bolts are heavy duty mo-fos, I hope you got rated bolts. Not just ones with the right thread pitch. Just sayin'.
 

96blak54

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Im thinking the flywheel orientation is off. Their really is only one way to bolt a flywheel to a modular, but a second position can be easily forced. The crank bolts holes are not exactly evenly spaced and when installing the flywheel, searching for the correct orientation can be confusing for the novice installer. If any of the bolts were forced on, im gonna say the orientation is off creating off balance. Hand tight all the bolt first! No tools! Once all bolts are in by hand then use force...lol
Dirt between the 2 mating faces, ...crankface and flywheel face could be a possibility.
 

dirtyred11

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When you say didn't fit specify what you mean. All your going to see is the teeth on the flywheel once the clutch us on.
i'm referring to the clutch disc, on the smaller flywheel the 11'' clutch disc was very close to the holes where you bolt the pressure plate to so of course it didn't fit.
 

dirtyred11

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Also, one other thing I forgot to mention. Flywheel bolts are heavy duty mo-fos, I hope you got rated bolts. Not just ones with the right thread pitch. Just sayin'.
I reused the flywheel bolts, I went to Ace to get the pressure plate bolts and the guy said they were the hardened ones.
 

dirtyred11

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are you sure the flywheel you bought is the correct balance for your engine?
That is one thing I've been steady wondering, but I was thinking that as long as the flywheel would bolt up and would spin right then there shouldn't be a problem. (Let me explain what I just said) Ok an example would be like the pulleys on the front of your engine, you can use underdrive pulleys and we know that they are smaller and weigh less but they still work and spin correctly.
 

96blak54

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Ok...let me get this straight...from what you just typed.... im thinking you just bolted the flywheel up? And forced the bolts in?
The flywheel only bolts on in one position. Its not like mounting a wheel and can go any orientation. Their is but only one correct position the flywheel can go. If the bolts were forced the flywheel is in the wrong position. I know this sounds stupid since the engines are neutral balanced, but if the orientation is wrong and bolts were forced the flywheel is not properly seated because of the bolts binding.
 

OnyxCobra

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even a flywheel with the wrong balance would still probably bolt on properly, but you'd get a vibration because the balance is off. so just because the flywheel bolted on properly doesn't necessarily mean it's the right one.
 

dirtyred11

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Ok...let me get this straight...from what you just typed.... im thinking you just bolted the flywheel up? And forced the bolts in?
The flywheel only bolts on in one position. Its not like mounting a wheel and can go any orientation. Their is but only one correct position the flywheel can go. If the bolts were forced the flywheel is in the wrong position. I know this sounds stupid since the engines are neutral balanced, but if the orientation is wrong and bolts were forced the flywheel is not properly seated because of the bolts binding.
Ok I know that it can only go on one way correctly so I did check different positions before I mounted it and the bolts did go in easy.
 

dirtyred11

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even a flywheel with the wrong balance would still probably bolt on properly, but you'd get a vibration because the balance is off. so just because the flywheel bolted on properly doesn't necessarily mean it's the right one.
So are you saying I need to see if the flywheel is balanced correctly or it may be the wrong flywheel even though it bolted up and the clutch fit it?
 

96blak54

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Unlike the smallblock engines the modulars are internally balanced (thank you Ford!) and has no need for offset weighted dampeners or flywheels, but this is not to say your new nodulariron (?) flywheel is correctly neutrally balanced.
Long story short here and I know you dont want to hear this, but.... (sigh)....youre just going to have to bite the bullet and pull it back apart. If you tackle the job, just post questions here....we got your back mang.
 

Wichers123

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First off 96-98 cobras use a t45 trans/8bolt crank. so a 8bolt flywheel is the one to use, then you should be using a 10.5" clutch. The
last question did you put the pilot bearing in the flywheel. If you didn't pull it now before you jack up the input shaft bearing in the trans.
 

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