CF 2 Clutch pivot Ball
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
CF 2 Clutch pivot Ball
Has anyone had to change to an adjustable clutch pivot ball when using a Centerforce II clutch set?
I've read here of the need when using a Dual Friction but not CF2. I have new flywheel and CF2, and have verified the correct throwout bearing etc. but have a high pitched pedal vibration at higher rpm's (above 3k), no shifter vibration or anything felt in the car only the pedal. CF told me the geometry for the TO bearing contact angle might be off, to see where the fork comes out of the bell housing, it should be approx. centered. Mine is not and is towards the rear of the car. Everyone I've spoken to so far locally says the standard pivot should work fine for this clutch and thy've never had to use an adjustable one.
Anyone have any thoughts?
Bill
I've read here of the need when using a Dual Friction but not CF2. I have new flywheel and CF2, and have verified the correct throwout bearing etc. but have a high pitched pedal vibration at higher rpm's (above 3k), no shifter vibration or anything felt in the car only the pedal. CF told me the geometry for the TO bearing contact angle might be off, to see where the fork comes out of the bell housing, it should be approx. centered. Mine is not and is towards the rear of the car. Everyone I've spoken to so far locally says the standard pivot should work fine for this clutch and thy've never had to use an adjustable one.
Anyone have any thoughts?
Bill
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Did you check everything out, dimension wise, per their installation instructions?
My dimension from the ball face to where ever they tell you to measure to, don't remember right now, was right on. So no adjustable ball was needed.
My dimension from the ball face to where ever they tell you to measure to, don't remember right now, was right on. So no adjustable ball was needed.
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Are you sure the fork didn't move inward a bit causing the angle to be off? I had to reposition mine to get it in the proper position. Is the new flywheel as thick as the old one and is the new clutch plate and pressure plate the same thickness toward the bearing retainer? Small differences in these deminsions will change the distance the fork has to travel before the throwout bearing engages the pressure plate fingers; which could cause you to have to use an adjustable pivot stud.
Bernie
Bernie
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I have to admit, I did a poor job verifying everything with this clutch installation. I listened to a couple of guys who told me they use them all the time and they never go through that. Time to pay the piper now!
I was just out looking at it, took the boot off so I could see inside....even though the fork doesn't exit the slot in the bellhousing in the center, I can see the TO bearing touching the PP fingers and it really looks like it hitting it squarely. It is difficult to see in there for sure but I don't know, this whole things sounds fishey. I'm wondering if the TO bearing is bad.
Bernie, do you mean the ball wasen't seated in the depression for it in the fork?? I didn't use a mic on the flywheel, I layed them side by side on a flat top and put a straight edge across them and they looked equal, old and new, but they could have been slightly off. Flywheel was GM for this engine (ZZ4) that others have used sucessfully. Not sure with this clutch though.
Man I hate to take this whole thing apart again!
Bill
Does this look like a bad angle??
I was just out looking at it, took the boot off so I could see inside....even though the fork doesn't exit the slot in the bellhousing in the center, I can see the TO bearing touching the PP fingers and it really looks like it hitting it squarely. It is difficult to see in there for sure but I don't know, this whole things sounds fishey. I'm wondering if the TO bearing is bad.
Bernie, do you mean the ball wasen't seated in the depression for it in the fork?? I didn't use a mic on the flywheel, I layed them side by side on a flat top and put a straight edge across them and they looked equal, old and new, but they could have been slightly off. Flywheel was GM for this engine (ZZ4) that others have used sucessfully. Not sure with this clutch though.
Man I hate to take this whole thing apart again!
Bill
Does this look like a bad angle??
Last edited by TopGunn; May 11, 2006 at 09:07 PM.
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Bill, I had mine in and out more times than I would like to count when I did my auto to 5 speed conversion. Your throwout bearing could be bad but I doubt it. It should turn smoothly but not have any slop in it. If it has any side to side movement within the bearing that would cause a vibration at higher RPM. Did you install the throwout bearing in the right direction? You probably didn't, but I had to ask. I finally had to use an adjustable pivot stud and kept adjusting it until the fork was very close to the front of the bellhousing. This keeps the throwout bearing close to the pressure plate springs without actually touching and gives the slave cylinder a deeper throw to release the clutch plate. Per recommendations from Carguy4sure I used liquid metal to bond the jam nut to the stud and the bell housing so the nut could not back off. I hope this helps a little and the second time is easier than the first. I also installed studs on the bellhousing instead of using bolts to attach the transmission to the bellhousing; it makes installation so much easier ( great tip from Norval).
Bernie
Bernie
Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Your bad. Listening to the bench racers rather than checking things as CF tells you to do.
Let's see, doctor says take 1 pill every 6 hours, buddy (bench racer) says take 1 pill every 4 hours and double up on Sunday.
Who you going to trust??
Let's see, doctor says take 1 pill every 6 hours, buddy (bench racer) says take 1 pill every 4 hours and double up on Sunday.
Who you going to trust??
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Bill,
I didn't see you picture before I posted. If the slave were installed, you could better tell about the angle but it does look ok to me. another thing that could cause that vibration is having the throwout bearing too close to the pressure plate springs where it actuall touches. Any vibration would transfer thru the pressure plate thru the throwout bearing and fork to the pedal. I just realized you probably do not have a hydraulic system. Have you tried adjusting the linkage at the fork in our out a little at a time to see if the vibration goes away?
Who is a bench racer?
Bernie
I didn't see you picture before I posted. If the slave were installed, you could better tell about the angle but it does look ok to me. another thing that could cause that vibration is having the throwout bearing too close to the pressure plate springs where it actuall touches. Any vibration would transfer thru the pressure plate thru the throwout bearing and fork to the pedal. I just realized you probably do not have a hydraulic system. Have you tried adjusting the linkage at the fork in our out a little at a time to see if the vibration goes away?
Who is a bench racer?
Bernie
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I deserve a beating for sure on this one for not checking stuff better. I put it all together on the motor when it was outside the car and it looked perfect.
There's a ton of free play in the pedal Bernie, and the return spring on the linkage keeps the TO bearing away from the fingers by a long way.
No problem on the comment on the TO bearing. I was really diligent about putting it in correctly, they included a picture with the clutch and I made sure I followed it so I'm pretty sure the springs are in the right place. I do remember the thing didn't look centered on the fingers but they said it's made that way.
I'll try screwing around with the linkage adjustment but this thing shifts smooth and is absolutely quiet and smooth as a baby's rear end below 3k rpm.
There's a ton of free play in the pedal Bernie, and the return spring on the linkage keeps the TO bearing away from the fingers by a long way.
No problem on the comment on the TO bearing. I was really diligent about putting it in correctly, they included a picture with the clutch and I made sure I followed it so I'm pretty sure the springs are in the right place. I do remember the thing didn't look centered on the fingers but they said it's made that way.
I'll try screwing around with the linkage adjustment but this thing shifts smooth and is absolutely quiet and smooth as a baby's rear end below 3k rpm.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Bill,
If you have that much free travel, it sounds as if all you need to do is adjust your linkage to get most of the free travel out of the linkage. It also sounds like your clutch is working just fine if there is no vibration when you pull out. I wouldn't pull the tranny until I did everything I could to get the slop out of the linkage. Just one question though, does your linkage have a lot of wear in the pivot joints and does it have a spring that keeps it tight when you aren't depressing the pedal. A weak spring, worn linkage, as well as, your linkage just needing adjustment could cause your problem.
If you are not concerned about keeping it original, you should really consider going to a hydraulic setup sometime. Easy to install, no adjustments, no linkage to wear out; just a suggestion.
Bernie
If you have that much free travel, it sounds as if all you need to do is adjust your linkage to get most of the free travel out of the linkage. It also sounds like your clutch is working just fine if there is no vibration when you pull out. I wouldn't pull the tranny until I did everything I could to get the slop out of the linkage. Just one question though, does your linkage have a lot of wear in the pivot joints and does it have a spring that keeps it tight when you aren't depressing the pedal. A weak spring, worn linkage, as well as, your linkage just needing adjustment could cause your problem.
If you are not concerned about keeping it original, you should really consider going to a hydraulic setup sometime. Easy to install, no adjustments, no linkage to wear out; just a suggestion.
Bernie
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Bernie,
No wear in the pivot points, the clutch fork is pretty new and the rod is brand new last year. Yes I do have the spring on the rod that keeps the TO bearing away from the fingers when it's relaxed. Anyone riding in the car would never know this is happening, it's strictly in the clutch pedal like a high frequency vibration, like a vibra-peen engraving pencil on the bottom of your foot. You take off in 1st and it feels perfect. If you shift under 3K rpm there's no problem. But if you jump on the gas and bring the rev's up and shift at 3-4K, you can really feel it in the pedal. The shifter is smooth as silk.
If it isn't pouring out tomorrow I'll adjust a bunch of the free play out and see what happens and let you know.
Thanks for the reply's.
Bill
No wear in the pivot points, the clutch fork is pretty new and the rod is brand new last year. Yes I do have the spring on the rod that keeps the TO bearing away from the fingers when it's relaxed. Anyone riding in the car would never know this is happening, it's strictly in the clutch pedal like a high frequency vibration, like a vibra-peen engraving pencil on the bottom of your foot. You take off in 1st and it feels perfect. If you shift under 3K rpm there's no problem. But if you jump on the gas and bring the rev's up and shift at 3-4K, you can really feel it in the pedal. The shifter is smooth as silk.
If it isn't pouring out tomorrow I'll adjust a bunch of the free play out and see what happens and let you know.
Thanks for the reply's.
Bill
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Well, the rain finally stopped so I've been screwing around with the clutch adjustments and checking things over as best I can. No change at all. What I did discover is that it only happens when power is applied, as soon as I take my foot off the gas it stops, gas applied again and it immediately starts again, off the gas and it's gone. All of this with my foot pressing lightly on the pedal so there's some pressure on the PP fingers. And maybe vibration is the wrong word, it's more like a grinding feeling rather than a pulsation.
That angle relationship might be a cause of some problems but I'm not convinced it's the cause of mine. The Vette shop that helps me out sometimes, has been putting these things in for several years without changing pivot ball lengths. He always installs a new one and a new fork but never changes the lengths.
I hate to say it but it looks like a weekend on my back again pulling this thing apart. I am definately not happy.
Bill
That angle relationship might be a cause of some problems but I'm not convinced it's the cause of mine. The Vette shop that helps me out sometimes, has been putting these things in for several years without changing pivot ball lengths. He always installs a new one and a new fork but never changes the lengths.
I hate to say it but it looks like a weekend on my back again pulling this thing apart. I am definately not happy.
Bill
Thread Starter
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Thought I'd post the findings for the next guy. (Who I hope this never happens to).
What I found was the pilot bushing was turning in the back of the crank. The OD measured .010 smaller than when it was new. In fact when I pulled the transmission the bushing fell out!
When I installed this thing I put it in the freezeer overnight and still had to tap it in with a rod so it was a very tight fit. It's a NAPA long style bushing and is non-magnetic. The leading edge has a huge countersink so tapping it in did not crush the ID and the ID still measures about .591.
I do remember having to pull the transmission in the last 1/2" by evenly tightening the transmission bolts, even with the clutch depressed it was still snug.
This is a GM crate motor with a GM bellhousing off my old motor and it dropped right on the alignment pins. I'm going to get a dial indicator and check it for concentricity but I can't imagine why it should be off.
So far no-one I've talked to has ever heard of this before (lucky me) but I'll post my results.
Bill
What I found was the pilot bushing was turning in the back of the crank. The OD measured .010 smaller than when it was new. In fact when I pulled the transmission the bushing fell out!
When I installed this thing I put it in the freezeer overnight and still had to tap it in with a rod so it was a very tight fit. It's a NAPA long style bushing and is non-magnetic. The leading edge has a huge countersink so tapping it in did not crush the ID and the ID still measures about .591.
I do remember having to pull the transmission in the last 1/2" by evenly tightening the transmission bolts, even with the clutch depressed it was still snug.
This is a GM crate motor with a GM bellhousing off my old motor and it dropped right on the alignment pins. I'm going to get a dial indicator and check it for concentricity but I can't imagine why it should be off.
So far no-one I've talked to has ever heard of this before (lucky me) but I'll post my results.
Bill
