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Looking at the picture of the diaphragm mounted to the flywheel, there does not look like there is enough distance between the diaphragm fingers and the hub of the clutch disk.
The picture maybe misleading but double check that you installed the clutch disk correctly.

I've had a diaphragm break and crack the mounting tabs of the clutch. It didn't stop working until one was totaling broken and another had a big crack. So, one bad bolt would have most likely not caused what you have experienced.

Later,
Eldon
 

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Looking at the picture of the diaphragm mounted to the flywheel, there does not look like there is enough distance between the diaphragm fingers and the hub of the clutch disk.
The picture maybe misleading but double check that you installed the clutch disk correctly.

I've had a diaphragm break and crack the mounting tabs of the clutch. It didn't stop working until one was totaling broken and another had a big crack. So, one bad bolt would have most likely not caused what you have experienced.

Later,
Eldon
Here's a shot of my ACT clutch for reference. Installed about a month ago.

1280659
 

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Since the wear on the pressure plate and flywheel are both on the one side it looks like the pressure plate/clutch were sitting cockeyed on the flywheel? Hard to say without seeing it when it was together in person...
 

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Discussion Starter · #46 ·
Looking at the picture of the diaphragm mounted to the flywheel, there does not look like there is enough distance between the diaphragm fingers and the hub of the clutch disk.
The picture maybe misleading but double check that you installed the clutch disk correctly.

I've had a diaphragm break and crack the mounting tabs of the clutch. It didn't stop working until one was totaling broken and another had a big crack. So, one bad bolt would have most likely not caused what you have experienced.

Later,
Eldon
Morning Eldon, I've had the flywheel off this morning and it's physically impossible to get the clutch disk in backwards, I'm not sure what else I could do to get it wrong so maybe just an angle/photography thing.

Since the wear on the pressure plate and flywheel are both on the one side it looks like the pressure plate/clutch were sitting cockeyed on the flywheel? Hard to say without seeing it when it was together in person...
I think the burn marks are just evidence of the brute force I used to try and 'unstick' the clutch from the flywheel. I'm not sure if it's evidence of the problem, or just caused by my attempts to remedy the problem.

I've just been playing with the flywheel, clutch and pressure plate assembly on the bench trying to figure out what I could do wrong to cause the friction discto be on some sort of angle and I just can't figure it out. With the bolts torqued down that friction disc is not going anywhere, it looks totally flush all the way around.

With the pressure plate bolts just done finger tight, there's a uniform 26mm gap between the finger tips and the clutch hub. When torqued down this drops to 14mm. Comparing with the stock assembly, this seems to be very similar.

I played around a bit on the stock assembly, undoing one bolt and leaving the rest done up etc. There's a clear distortion in the formation of the fingers if this is done badly enough - something I would have definitely noticed (and seen when looking back of pictures of the original install) so I'm becoming unconvinced that the pressure plate fitment is to blame.

I think that leaves only the input shaft as a potential problem? I've not inspected it properly yet, but I did check the clutch can slide easily across it (seems it can), but I'll give it a proper magnifying glass inspection later to see if I can find any burrs or something that may have been catching the clutch. I really doubt it though :(
 

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Discussion Starter · #47 · (Edited)
Just to add, not sure I posted this yet. This is a shot I took before removing the clutch. I span the flywheel around and looked through each "inspection gap" in the assembly like this. Everything looked to be flush and lined up.

 

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Discussion Starter · #48 ·
OK Mystery potentially solved.

I had a generous offer from Dave @ Seriously Lotus here in the UK to compare my clutch with one he had off the shelf. Considering he didn't even supply the original I thought this was rather generous, and he's fairly local so we made it happen this afternoon. We wanted to rule out the chance I had the wrong item.

Sure enough, the clutches were identical but we did go on to do some testing with his hydraulic press. When pushing on the fingers of my pressure plate, 2 thirds of the plate lifts up but the final third remains planted firmly down on the clutch disc. This is exactly where the burn marks are on the pressure plate too.

So it looks like my pressure plate is broken, there's no externally obvious evidence of damage or mishandling, so really can't say what. I've taken a new clutch away from Dave to allow me to get on with re-assembly this weekend whilst the warranty claim goes in with CC. Hopefully they don't push for "user error" but I'm just relieved to finally have my "smoking gun".

Top marks to Seriously Lotus, but also fair to shout out to CC and the original vendor because they're all working with me to try and sort it, it's been a pleasant customer service experience all round so far!

Thanks again for the help, hopefully this goes smoothly from now...
 

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I've had one clutch package that produced wear marks like yours. Mine were more one side of the flywheel. The clutch would disengage but would never stop chattering. It finally broke a piece off of the disk and jammed up the diaphragm. I sent the parts back to the vendor and they were told by their supplier that I did not have the motor and trans lined up. I checked that the dowel pins were still there and they were. After changing out the diaphragm, disk and replacing the surface plate on the flywheel, it worked much better. Within a several hundred miles the diaphragm failed by breaking the mounting tabs and I stopped using that manufacturer.

From the wear marks on the diaphragm and flywheel, you have a high spot that is pinching the clutch disk. Just breaking loose the disk will not create those kind of burn marks. I would almost bet that if you could get a little more motion out of the clutch fork, you would have a bad chatter when engaging the clutch. The only other thing that I could think of before replacing parts would be to check to make sure the the flywheel was mounted flat against the crank. If it wasn't, it could create the wear pattern that you are seeing. Otherwise, I would check the flatness of the diaphragm and the flywheel.

Later,
Eldon
 

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I was going back through my memory last night and I also had a Competition clutch that I installed that never released fully from new (was installed in a paddock sooooooo who knows). I never looked into why and just replaced it and never thought about it again.
 

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Discussion Starter · #53 ·
Drama might not quite be done yet...

My first attempt to do the clutch had me using a (new) OEM release bearing from Toyota as I'd had some generic advise that kit supplied bearings are normally of inferior quality, not singling out competition clutch as such - but still worth keeping in mind.

When I discovered the faulty clutch, I knew I potentially had a warranty battle on my hands so I used the CC supplied bearing second time around just to cover my bases. Now a few days later, the car has done maybe 20miles and I now have a 'boost leak' type noise when revving the engine with the clutch disengaged (so when the bearing is pushing on the diaphragm fingers).

I'm just a little bit annoyed, but trying not to panic yet as I know everything needs time to bed in... but I wasn't expecting a noisy bearing :(

The saving grace is that it only seems to occur when the car first starts up and so is cold. As soon as I drive the car a little bit, it goes silent and I can't replicate it so perhaps it's something I'll live with rather than dropping the box for a third time...
 

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It could be the cold grease in the bearing is causing a little drag. Eventually the bearing balls will push some of the grease away and free it up.
 

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Discussion Starter · #55 ·
It could be the cold grease in the bearing is causing a little drag. Eventually the bearing balls will push some of the grease away and free it up.
Fingers crossed it's something like that, trying to keep hopeful about it! I'm not sure I have the stamina to remove my box again!
 
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