Centerforce Clutch?
Thread Starter
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
Centerforce Clutch?
I am replacing the clutch in my 70 LS5. Both a local Corvette shop and a machine shop where I had my flywheel refaced recommended a Centerforce clutch. The Corvette shop told me they had a lot of trouble with an unknown brand replacement, finally went to the Centerforce, no issues from then on. The machine shop told me the Centerforce has a lighter spring making the clutch easier to work. It uses weights which apply more pressure using centrifugal force.
I already bought a replacement from Paragon, still in the box. I'd like to hear about others experiences before deciding to either install the Paragon clutch or buy a Centerforce. I never want to deal with this clutch again if avoidable.
I already bought a replacement from Paragon, still in the box. I'd like to hear about others experiences before deciding to either install the Paragon clutch or buy a Centerforce. I never want to deal with this clutch again if avoidable.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
Center forces are great clutches, you just have to stay on top of the pedal free play adjustment for the 1st 1500-3000 miles. If you fail to do this.....the clutch disc will bed in and thin down....then the Belleville spring will move rearward and at higher RPMs the weights on the spring will flex it back into contact with the throw out bearing and unload the pressure plate at higher RPMs. After initial break in they perform quite well for 10K+ miles between adjustment checks. Go with the dual friction model with that LS-5. I hope the flywheel is surfaced with a DCM type surfacer even new flywheels can benefit from this process.
Pro
Joined: May 2011
Posts: 722
Likes: 58
From: Karlsruhe (Germany)
Back then I had a standard LUK clutch with my LS5, it was easy to engage and clamped good. Then I switched to the zz502 and the clutch was still working good.
After switching to the TKO I needed a new clutch and decided to use a centerforce.
The dual friction is really more hard to push than the LUK was.
Additional the pivotaball must be adjusted for the centerforce (great if you find this out after the tranny is installed and the car on the road).
Well - the centerforce works good, clamps better than the LUK, but I would recomend the LUK for your application. It´s cheaper too.
After switching to the TKO I needed a new clutch and decided to use a centerforce.
The dual friction is really more hard to push than the LUK was.
Additional the pivotaball must be adjusted for the centerforce (great if you find this out after the tranny is installed and the car on the road).
Well - the centerforce works good, clamps better than the LUK, but I would recomend the LUK for your application. It´s cheaper too.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Back then I had a standard LUK clutch with my LS5, it was easy to engage and clamped good. Then I switched to the zz502 and the clutch was still working good.
After switching to the TKO I needed a new clutch and decided to use a centerforce.
The dual friction is really more hard to push than the LUK was.
Additional the pivotaball must be adjusted for the centerforce (great if you find this out after the tranny is installed and the car on the road).
Well - the centerforce works good, clamps better than the LUK, but I would recomend the LUK for your application. It´s cheaper too.
After switching to the TKO I needed a new clutch and decided to use a centerforce.
The dual friction is really more hard to push than the LUK was.
Additional the pivotaball must be adjusted for the centerforce (great if you find this out after the tranny is installed and the car on the road).
Well - the centerforce works good, clamps better than the LUK, but I would recomend the LUK for your application. It´s cheaper too.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
I have a Centerforce Dual Friction (11") in my 78.
Versus the stock replacement I had before, it feels about the same in effort but engages quite a bit higher than the stock clutch. It holds my 480lb-ft torque very well.
The tires (255-45/18 summer tires) give up before the clutch does.
I am running a hydraulic setup though (Wilwood master, RAM slave).
Versus the stock replacement I had before, it feels about the same in effort but engages quite a bit higher than the stock clutch. It holds my 480lb-ft torque very well.
The tires (255-45/18 summer tires) give up before the clutch does.
I am running a hydraulic setup though (Wilwood master, RAM slave).
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
no no no ... absolutely not..... when a top goes off balance, does it recenter itself? no...
think about it... with the weights on one side .... how would the center weights ever be able to pull the outer weights back when they are creating more force due to being further from the center....
I have run these clutches for years, and i should have seen this before....
it was always strange... sometime the engine felt smooth as silk... other times i could feel a slight vibration... got rid of the CF clutches... all went smooth.... never ever again
think about it... with the weights on one side .... how would the center weights ever be able to pull the outer weights back when they are creating more force due to being further from the center....
I have run these clutches for years, and i should have seen this before....
it was always strange... sometime the engine felt smooth as silk... other times i could feel a slight vibration... got rid of the CF clutches... all went smooth.... never ever again
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Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
OK a difference of opinions. I have run the same CF clutch for 10 years just replace the the friction disk. When you have it apart you can move the weights anywhere you want, by design they center unless there is something wrong with the clutch and not allowing the weights to move. 
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
OK a difference of opinions. I have run the same CF clutch for 10 years just replace the the friction disk. When you have it apart you can move the weights anywhere you want, by design they center unless there is something wrong with the clutch and not allowing the weights to move.
Please explain to me, how off center weights on a spinning top will/or can self center themselves?
not physically possible.... when the weights sling over to one side... thats where they are at... period....
Then I would feel the vibration... then i would depress the clutch... making the weights somewhat centered via the throughout bearing... then once released... the weights if ever so slightly to just one side or the other (and this will always be, as it is never perfectly allinged or weighted) will once again slide over to one side, inducing vibration.....
my 427 is so well balanced that the only way for me to know when to shift right now is the tac.... at 7000+rpm its as smooth as any stock C6 engine at 3000rpm..... this has created its own problem... shift light is the next step.... with the center force i could feel the vibration and know when to shift.... this is my no means a first time experience with CF... just took me a while to figure the problem out...
imho... the CF clutches are junk.
Pro
Joined: May 2011
Posts: 722
Likes: 58
From: Karlsruhe (Germany)
My understanding is, that the weights are centered by the throwout bearing when it goes into the clutch and presses the springs.
One time I had a vibration feel too, after pressing the clutch it went away.
One time I had a vibration feel too, after pressing the clutch it went away.
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Hi
I'm also running the dual friction behind my L71 and fwd of my T56 and am still happy with it. I haven't felt any unusual vibration yet , but seldom spinn over 4000 RPM.
The dual friction requires a adjustable pivot bolt ( like already mentioned ) because the original one is too short.
Rgds. Günther
I'm also running the dual friction behind my L71 and fwd of my T56 and am still happy with it. I haven't felt any unusual vibration yet , but seldom spinn over 4000 RPM.
The dual friction requires a adjustable pivot bolt ( like already mentioned ) because the original one is too short.
Rgds. Günther
Burning Brakes
Joined: Oct 2008
Posts: 955
Likes: 50
From: Jersey Shore
The CF weights DO center themselves once they start spinning... Since the fingers they ride on are pointing slightly outward they will equalize at speed. The point of the weights is to pull themselves backwards putting more clamp force on the pressure plate. When they move backwards they have to equalize since they all weigh the same and hence, carry the same force. If the fingers were 100% in line with the moment arm of rotation, then they would not center.
The weights can become unbalanced though... If you live/drive in highly "corrosive" areas (ie: near the beach) the weights and fingers can rust causing them to stick and not self center. That being said, I live near the beach, and have a CF clutch with the weights and dont have any issues (yet?)
The weights can become unbalanced though... If you live/drive in highly "corrosive" areas (ie: near the beach) the weights and fingers can rust causing them to stick and not self center. That being said, I live near the beach, and have a CF clutch with the weights and dont have any issues (yet?)
Melting Slicks
Joined: May 2004
Posts: 2,743
Likes: 843
From: Gulf of America
2023 C7 of the Year Finalist - Unmodified
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I had a blueprinted engine built for my vette awhile back. Against my engine builder's suggestion, I went with a Centerforce Dual Friction assembly. Right off the bat, I had vibration issues. I chased the vibration for over a year and finally called my engine builder about it thinking it had to be an internal engine problem. He asked what kind of clutch did I install. When I told him it was an Centerforce DF, he told me to pull the trans and look at the clutch. As soon as I pulled the trans out, I could see what the problem was. The ring of weights were slung over to the side causing the vibration. The weights were not stuck as I could take them and move them all around by hand. But from the wear marks on the clutch fingers, it was obivious they had been running off center the entire time causing the vibration. He explained that they could never get a Centerforce Dual Friction clutch to balance out perfectly because of the moving weights. To him, it didn't make sense to have an engine built, pay to have the engine rotating assembly balanced perfectly and then hang a clutch on it with movable weights. I removed the Centerforce clutch and installed a McLeod clutch assembly and the vibration was gone. That was my experience. Some people have luck with them but I didn't.
Safety Car
Joined: May 2004
Posts: 4,364
Likes: 1,588
From: los altos hills california
The CF weights DO center themselves once they start spinning... Since the fingers they ride on are pointing slightly outward they will equalize at speed. The point of the weights is to pull themselves backwards putting more clamp force on the pressure plate. When they move backwards they have to equalize since they all weigh the same and hence, carry the same force. If the fingers were 100% in line with the moment arm of rotation, then they would not center.
I tried looking up the original patent on this concept but was unsuccessful at finding an explanation as to how this was supposed to work. Centerforce could do themselves a big favor by posting a video of this centering force at work.
I have had mixed results with these clutches. One thing I have discovered is it is very important to use their alignment pins.
Drifting
Joined: Oct 2005
Posts: 1,331
Likes: 479
From: Appleton Wisconsin
I also chased a vibration in my 454 for years bought a Fluidampner which helped. I finally took the transmission out and the weights were off center, bought a different clutch and vibration was gone.
Pro
Joined: Aug 2010
Posts: 698
Likes: 8
From: Stockholm Sweden
I hav been running my Centerforce DF for 3 years without any hickups. 
I like the CF light pedal and it haven't had any problems holding ether in the street or on the track and i have had no issues with vibrations.
For 2014 I replaced the DF this year with the Centerforce LM series clutch that has the same weight system but is 3kg lighter than the CF due to its aluminium body.
Quite quick i discovered that the LM series sinter disk was a bit to rough for me and i replaced it with the ordinary DF disc and am now as pleased as before.
//Ricky.
I like the CF light pedal and it haven't had any problems holding ether in the street or on the track and i have had no issues with vibrations.
For 2014 I replaced the DF this year with the Centerforce LM series clutch that has the same weight system but is 3kg lighter than the CF due to its aluminium body.
Quite quick i discovered that the LM series sinter disk was a bit to rough for me and i replaced it with the ordinary DF disc and am now as pleased as before.
//Ricky.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
with the center force i could feel the vibration and know when to shift.
Sounds like you got one youre happy with now though.
Maybe Im lucky mines 14 yrs old and no issues so far and holds plenty of power. Now that I said that it will start slipping next time out
Melting Slicks
Joined: Dec 2009
Posts: 3,233
Likes: 657
From: Thunder Bay
I've been hearing of the balance problems with Centerforce clutches for years, and I can certainly understand the concerns. In fact, I can't figure out why they wouldn't all be out of balance. However, with that said, I have two of them. One in my 66 and one in my 79. Neither has a vibration problem. My buddy also has a CF in his 350 S10 and he has no vibration problem either. Not sure why some do and some don't, but I've had good luck with them.