[Node]

Bad news everyone.

It looks like maybe the Fidanza may not compatible with the Uniclutch or mine is out of spec.

The last time I had the transmission out I thought that maybe the aftermarket throw out bearing had failed. Unfortunately that is not the case. It appears that the clutch pack has been rubbing on the thrown out fork. Just barely but enough to cause a hell of a racket and very much misbehave when hot. Keep in mind the Throw out, pivot fork and ball were all replaced the last time the noise was heard so these parts are not suspect.

The WORKING theory currently is that the flywheel (aluminum) and adapter ring (mild steel) have different thermal expansion coefficients. When we were dynamic balancing the flywheel and clutch, It was impossible to get the adapter ring onto the flywheel at freezing temperatures but it was a tight fit at room temperature. So, our theory is the ring expanded when the engine and clutch heated up during use and then warped; pushing the clutch pack toward the pressure plate. This explains why there was such difficulty shifting when hot.

Next steps:

1. Verify the height from the crank mounting face to the pressure plate mating surface of an OEM flywheel
2. Verify the height of the Uniclutch plus the offset of the warped adapter ring

I suspect that BOTH the Fidanza flywheel is out of spec (thickness) AND the adapter ring is warped toward the transmission (as can be seen in the pictures). The finding here may be that you cannot use an aluminum flywheel with the steel adapter ring due to the mounting method of the UC pack.

I have contacted Uniclutch for their assessment of what happened. But no matter what it looks like we have to switch to a heavier steel flywheel. If the Fidanza turns out to be out of spec then we are probably ok with just installing the Chromoly wheel. But if it is correct then we may need to consider machining the flywheel for this clutch to work properly when it gets hot. And FWIW, the issues were MUCH worse when hot. This sucks because the total package weight will go up two pounds but there's no way around it it seems.

Damaged TO fork where clutch pack started rubbing

Damage to the clutch pressure plate from rubbing on the T.O. fork at the pivot point

 

[Funnyman]

Those are the dimensions of a Competition Clutch, Fidanza and MWR. If it can help you checking if your Fidanza has bent/out of specs.

 

[Node]

Wholly crap it IS thicker! THANK YOU.!

I just bought a new adaptpter ring and a chromoly wheel from MWR. All new hardware is here to go with the new transmission.

I am going to consider machining the shoulder of the pivot ball by a couple millimeters too.

So,

1. Thinner wheel
2. Non warped adapter ring
3. Offset pivot ball

@Funnyman why do you know this stuff? And yes, I would like to confirm the FIdanza is ok. I have a friend who will probably want it since it won't fit in my setup.

 

[Funnyman]

@Funnyman why do you know this stuff? And yes, I would like to confirm the FIdanza is ok. I have a friend who will probably want it since it won't fit in my setup.

I like experimenting and trying stuffs making my own experience. Be sure that the Fidanza pressure plate is flat before sending to your friend. Over many miles/used, the pressure plate will curved in the center section, requiring replacing the Fidanza pressure plate and bolts.

 

[Node]

I like experimenting and trying stuffs making my own experience. Be sure that the Fidanza pressure plate is flat before sending to your friend. Over many miles/used, the pressure plate will curved in the center section, requiring replacing the Fidanza pressure plate and bolts.

View attachment 111297 View attachment 111298

We were running WITHOUT the friction surface on this wheel since the clutch pack doesn't use it. I still think it would be a good idea to confirm that the flywheel is OK dimensionally before putting it in another car. I don't expect damage. It looks like we got lucky and the fork was just touching the pressure plate but not binding with the ball. If it had I expect the flywheel would have died horribly from cycle fatigue.

I am in touch with Uniclutch rep already! They are fantastically responsive for being on the other side of the planet. FWIW, they did tell me they have an option for a thinner pressure plate cover that could be used with this combination package. But the question remains, why did the adapter ring warp? This is what we really need to understand. The clearance is one thing but the warpage further reducing the clearance is another.

 

[Funnyman]

The adapter ring wrapped because of used and has knowned 2 Stg.1 clutchs in his life. Around 110k miles if I remember right. The second Stg. clutch (me new owner) holded many street drag racing. Meaning why the adapter ring got overheat prints.

 

[Node]

The adapter ring wrapped because of used and has knowned 2 Stg.1 clutchs in his life. Around 110k miles if I remember right. The second Stg. clutch (me new owner) holded many street drag racing. Meaning why the adapter ring got overheat prints.

 

[Funkycheeze]

So the steel uniclutch plate bolted to the flywheel warped? Remember the expansion coefficient of steel and aluminum is very different. Perhaps that is part of the reason? Or differential heating? I think a steel FW is the fix here.

 

[Node]

So the steel uniclutch plate bolted to the flywheel warped? Remember the expansion coefficient of steel and aluminum is very different. Perhaps that is part of the reason? Or differential heating? I think a steel FW is the fix here.

The engine makes lots of power but nowhere near the rated 650 ft/lbs that this unit is rated for. So yes, I think that thermal differential is the ONLY thing that could have warped that ring in that way. Everything was dynamically balanced, checked and rechecked. I suppose the only other idea I have is that the clutch discs could have been warped or offset from each other but I can't think of a way that would cause axial thrust on the clutch pack.

The new adapter ring arrived today. I am going to put it on an end mill just to make sure it's flat. I also am going to take 2mm off of the pivot ball shoulder JUST to be sure even if this thing warps again, Ill have the clearance I need. The MWR chromoly wheel will be here Tuesday. Unfortunately, I'll be in Texas when it shows up. So, I'll have to wait until later in the week to fit this all up and start re-assembly with the new transmission, flywheel etc...

For those of you wondering why I am putting in this much effort for a clutch, look back at the start of the thread. This is the ONLY unit on the market with triple dampened sprung hub organic discs. It drives like an OEM clutch but handles 300% of OEM torque. So, this protects the transmission (to some degree) from the power this setup makes but also make driving the car a breeze. Its a twin disc with zero drive line chatter (ignoring the noise from this obvious little oopsie).

 

[Node]

!!!!WARNING!!!!

Ok, first let me say I am pissed and I am trying to keep my cool here. Also, the Uniclutch IS a good product. Or at least the clutch pack is. The interface to the adapter ring could use some more engineering effort.

I'll sum up with a TLDR.... The Uniclutch instructions for the Lotus are MISSING CRITICAL INFORMATION. The Lotus (Toyota C-Series & ZZ engines) require a shim, washer, spacer to offset the adapter ring from the flywheel mounting surface. THIS IS NOT IN THE ONLINE APPLICATION INSTRUCTIONS!

Ok, now the long write up with pictures.

A full measure up was required because the adapter ring was found to be broken and UC felt like the clutch pack was bottoming out against the flywheel. This could have been listed as a critical measurement to check but was never mentioned. We just took their instructions be correct.

Notice the outer edge just before the adapter ring where UC was making contact with the flywheel. It is only here because I was running without the friction surface.

The force of the improper assembly caused the ring to cycle fatigue and crack after a couple thousand miles:

 

[Node]

Proof that the offset was set up per the Exige instructions from UC

Link to UC instructions snapshot:
Dropbox

www.dropbox.com

 

[Node]

Note the offset step height of the flywheel:

This means the shim needs to be 0.74mm + 0.6mm (flywheel offset + UC offset) 1.34mm at a MINIMUM!!!!

 

[Node]

Decided to give myself a little safety margin. Made up six 1.43mm spacers and used the MWWR wheel. The step height with the new ring wasn't nearly as bad as the old one.

Ready to go back together. I upgraded to spherical bushings and replaced the cable clips while I was in there. Also modified the clutch fork retaining clip to pull the fork away from the clutch rather than letting it just flop around as was OEM. Fingers crossed!

 

[Node]

NOPE!

After all that it's still short by a couple mm.

Shorter MWR flywheel
Custom shims
Modified the retention spring to hold the fork on the ball.

I of course could modify the pivot ball or machine a recess in the aluminum flywheel. But at that point I may as well just buy an organic twin disc clutch from a competitor.

I have already wasted too many hours on this. I think even when I first put this in there was an issue because there was a noise then too. It must have always been making contact.

 

[Funkycheeze]

How does this work on the lotus? Is the fork different?

 

[Node]

How does this work on the lotus? Is the fork different?

Same exact part/s both Uniclutch and Toyota/Lotus.

EDIT: FWIW I have transmissions sitting here from a Celica, MR2 and Exige. The bellhousings, input shaft, clutch fork, TO bearing are all identical.

 

[carlbecker]

So is the flywheel the issue?

 

[Node]

So is the flywheel the issue?

Perhaps this ONLY works with the OEM flywheel. I have yet to measure that up but it is a great point. Maybe that's 4-5 mm thinner to the mounting point? This SHOULD have worked based on UC application testing AFAIK. Maybe I am missing something with the aftermarket flywheels.

Here's the key point: Who the hell is going to put in a UC Performance Clutch with an OE flywheel? Especially since the whole rotating assembly will be HEAVIER than stock! That's not going to happen often. At least 80% of installs are going to be with a Fidanza or MWR wheel.

 

[carlbecker]

If everything else is o e and works with lotus using Toyota parts then it sure looks like the flywheel is the culprit. I wonder what flywheel lotus uses.

 

[Node]

If everything else is o e and works with lotus using Toyota parts then it sure looks like the flywheel is the culprit. I wonder what flywheel lotus uses.

I wonder if it's the 1ZZ wheel. I don't think Lotus did anything other than receive a package from Toyota with a different spec for the shift linkage and gear ratios. You make a really good point. I DONT have the Lotus flywheel sitting here, just the transmission.

Here's the rub though. This is an MWR flywheel FOR an Exige and the Fidanza is FOR an Exige and the Uniclutch was FOR an Exige. The Exige transmission sitting here (broken but measurable) is, well, from an Exige. So, my only conclusion is that this just BARELY works with an OEM wheel.