mac79vette

Any one else have problems with there center force DF clutch. I suspect the weights go off center causing intermittent drive line vibrations. Also it shutters at low speeds such as backing out of my drive way. When the car is ran at the track or auto x it does not take long for its holding ability fades. It's release point is slightly different after a long hot highway drive vs cold.

a striper

The weights moved around on mine. I chased a vibration that would come and go until they shifted way off center and stuck there. That made the car shake very badly all the time. Never again for me.

jb78L-82

I consulted with my engine builder for the bottom end of my L-82 when I rebuilt it in 2014 about clutches and he suggested RAM HDX for high HP applications with stock clutch feel and I went with RAM....Might want to consider as a replacement if you go that route...real nice with stock clutch effort. I paid to have my flywheel and clutch balanced...very smooth with no vibration at mid to high rpm...I was shocked the first time I revved the motor compared to the OEM L-82/clutch/flywheel vibrations.

Big2Bird

I installed one in a friends 71 BBC. Car shook like no tomorrow. POS. Never again.

Mako72

Same here with a CF Dual friction, weights slung over to the side, wouldn't self center. Never again. Went with a McLeod. Vibration gone.

resdoggie

I have the CF DFX. No problems with it. It does have some chatter starting off but that's because it needs to rev a few hundred rpm's higher which most times eliminates it. Also, CF does state that for street use there maybe some clutch chatter. It sure does grab! I don't have any vibration issues either.

mac79vette

Mine also grabs really well until lit gets really hot, but to get that hot its got to be at a track, no issues on the street, or even the drag strip. I can live with the chatter but not the vibration. I guess the weights really move around because some times it's significantly worse than other times.

Can I remove the weights??

Gordonm

Yes you can. I removed the weights on mine years ago with no issues. The holding was the same. I would ditch the weights. Never liked that idea. My clutch held up fine after years of abuse running this way.

ignatz

How's this for off center! That would be the throwout bearing making these grooves.



I called them once and the tech said the weights contribute maybe 10% holding force at the RPM limit. Definitely a gimmick. If you ditch the weights which is easy to do, it is a pretty good clutch.

And yet ... a new CF clutch, with weights, in my car now works just fine. The new weight system appears to be a bit different from what I show here. It defies my understanding of centrifugal force to see how they would self center. Multiple sliding weights make for a somewhat complex dynamical system. I went so far as to try looking up their patent but was unsuccessful.

MotorHead

The weights work and they self center. When the DF first came out it was blamed for a myriad of vibration issues because when trying to solve a vibration problem the clutch was often looked at.

You can imagine how easy it was to blame the clutch when looking at it and the weights drooped downward off center. But if the fingers and weights are in good condition they will center themselves as soon as the engine starts up.

I have run the DF clutch for 10+ years and it handled power ranges from 400-600HP with absolutely no vibration or slipping. Matter of fact the same 10+ year old clutch clamps down hard on my 600HP 427ci small block on the street and at the drag strip.

I have only replaced the friction plate and the old pressure plate /clutch and the weights work perfect with 6000RPM shifts at the drag strip. That is more than enough proof I need to buy another one when and if the current one needs replacing.

ignatz

Care to explain why? And don't just answer "centrifugal force". The centrifugal force is omega-square x R, so the further out on R you are, the more the force. Hence the off center weights that are further out want to stay there. The only thing I can surmise is there is an offsetting force because the weights nearer the center are denser and their combined density makes it work. Also because the weights are sliding on the fingers which is not perpendicular to omega there is a vector component there. Perhaps a free body diagram, or .....

Clearly too my severely stuck weights require some sort of explanation. That was a fairly new clutch.

homestead

If it were me I and the pressure plate is still in good shape I would take the weights off and try it. I think the weights are a bit of a gimmick on that type of clutch myself. On racing pressure plates the weights are tunable and I don't see any of that on these. Just my 0.02 cents.....

l88rocket

I prefer the Dfx clutch, the last Dual friction I had I killed in 500 miles of just street driving trying to break it in

Perfmach1

My center force clutch disc lost half of the friction material on one side. 4000 miles on street tires no drag racing. POS.

MotorHead

Jeese you are making it hard because the weights are part of The Centrifugal Weight System and are designed to provide the clutch
with increased holding capacity as RPM increase.

Many things can cause a clutch failure and I didn't I didn't design the clutch nor did I install it in your car ( which could easily be the problem), phone this number and ask why your weights stuck : 928-771-8422
I know mine self center not sure about yours

ignatz

Sorry, I am not trying to yank your chain. Lots of discussion on this in previous posts including in part by me

https://www.corvetteforum.com/forums...ce-clutch.html

I can see that as the clutch spins up, the weights will all move outwards, and, because of the angle on the pressure plate fingers, they will exert additional clamping pressure. After thinking about this some more I'm guessing that if the restraining wire that passes through all of the weights was too short, all the weights can't fly out equally as far and that creates an imbalance, maybe? My conjecture about the mass density of the weights is probably overthinking things a tad.

I still have the clutch in the picture but seem to have lost the baggie full of weights that I removed so I can't check on that. Clearly my weights were badly stuck and for a completely stock clutch setup, throwout bearing, bell housing and all the linkage.

And the new clutch in my car, with a new weight configuration works just fine. No imbalance that I can detect.

Here's the new clutch. Notice that these weights are already out near the perimeter, so maybe that's all there is to it, not enough free play in the old design? You can see where the restraining wire ends at about the 1:00 position.

COOLTED

I have never liked the idea of the centerforce clutch. More stuff to go wrong. When I needed a clutch for my Shelby, I just bought an HD and was done with it.

Big2Bird

There are numerous HP clutches out there without dumb *** weights.

How could you do a proper static balance on that with them stupid weights flopping around?

MotorHead

Not sure if you can see it but the weights have an abnormal amount of crap around them. I can see that clutch getting out of balance very easily. The weights can't move because of all debris around them.

ignatz

As I said I still have the clutch so I checked and the crap is grease. Plus if you do the math, at say 6000 RPM for a maybe 1 oz. weight, there is a HUGE amount of force on each weight. A couple of 100 pounds if I got all my units right. They weren't stuck because of the crud. I'm still leaning toward the idea that once they get past a certain offset there is no self centering because the weights stuck at the end of the retaining wire are overpowering everything else.

If you look at the new clutch, CF has added another feature. Look carefully, after every three weights there is a sliding stop on each lever arm. Look at 6 o'clock for instance. I assume that is to keep the weights from getting out too far. Probably another band aid to prevent what happened in the first version.