dual mass to single mass clutch help

[JP422]

Ok, I'm a bit stumped, and would like to figure this out before I pull the tranny again.

I have a 1.9 Z3 and I pulled the old dual mass clutch assembly in favor of a Fidanza M3 ltw flywheel, an M6 sprung disk, and an M3 pressure plate. While the pieces were out, I checked clearances and it appeared that the clutch disk had to be flipped backward ("gear box side" toward the engine) for clearance of the disk's fatter sprung hub. The ltw flywheel was machined to clear the thicker hub too (flipped backward)... and if the disk is placed the right way, then it will hit the inside of the pressure plate (made for solid disk).

Everything bolted together perfectly with the disk flipped backward, but when I started the engine, and pressed the clutch, I could hear something hitting. I think it's the flywheel bolts tapping the clutch disk.

My questions:

-Does anyone has a similar setup and what they did.
-Do I need a pressure plate made for a sprung hub?
-Should I look for lower profile flywheel bolts or can I shave the bolt's heads a little?

I'm going nuts because after all this work, I'm SOOO close to finally driving my roadster again... and this is the last hurdle!

Please help me get the car back on the road!

Thanks!~
-Joe.

[FMD]

I'm pretty sure you need to use an M5 clutch / pressure plate when using single-mass / M3 flywheels.

[JP422]

When I had the clutch assembly mocked up, it all fit together perfectly (with the disk flipped)... but the only thing missing in this mockup test were the flywheel bolts.

Perhaps the M6 disk protrudes a hair more than the M5? Either that or the bolts that came w/ the Fidanza flywheel have taller bolt heads than BMW bolts...

**nevermind, the E34 M5 and E24 M6 disks are pretty much the same.

[JP422]

Well, just got off the phone w/ BimmerWorld (that's where I got my disk and pressure plate). On their website, it says a '96-99 M3 pressure plate is compatible w/ the E34 M5/M6 sprung disk they sold me. Unfortuneately, I was sent a '95 pressure plate. So far, their customer service has been very good (over the phone at least). I hope I can make time to pull the tranny this weekend to get to the bottom of this.

I don't know if anyone out there knows the difference, and can chime in, but I'm speculating the pressure plate on the '96-99 M3 has room for the sprung hub, and will allow me to install the disk the proper way so the disk wont be flipped. Then my flywheel bolt theory will not even be an issue.
Well... only time will tell now...

[edwinm703]

I am considering the same change out please post your findings as soon as you know.

Thanks.

[JP422]

Well, if you want a sure fire way not to have any issues...

1) Then a JB Racing ltw flywheel will allow the use of a sprung M5 disc (flipped backward) w/ any E36 M3 pressure plate for sure.

2) I'm still trying to figure out what the difference is between a '95 and a '96-99 E36 M3 pressue plate is. I wonder why BimmerWorld doesn't recommend the '95.

3) Another method is to get a E34 M5 pressure plate (which seems hard to find these days), and then I can install the disc facing the right way (w/ the sprung hub into the pressure plate). My only concern is if the TOB will meet the "fingers" in the same plate as an M3 plate (and I'm sure it will).

4) If I were to use a non sprung disc (solid hub), all this could be a non-issue, but I want it sprung (and Fidanza recommends it too). I'll be calling Fidanza tomorrow to get more info.

Anyway, I hope to have some answers by this weekend~

[JP422]

Ok, got an update...



1) The Fidanza flywheel is perfectly fine. The flipped M5/M6 sprung hub fits fine with no issues.



2) The rubbing I got was from the '95 M3 pressure plate. When bolted on the FW, the fingers go deeper in, and when the clutch pedal is pressed, the release fork rubs the pressure plate. Supposedly a '96-99 M3 PP has fingers that are bent outward and help offset this.



3) An E34 M5 pressure plate WILL fit of course, but are quite hard to find by itself, and if found, they are very expensive, and a bit heavier (kind of goes against the while LTW FW). This will allow the sprung disk to fit properly, but since the aftermarket flywheel is allready designed to have a sprung disk in it's cavity, it seems redundant to have the M5 PP...



4) Hopefully BimmerWorld will do good and exchange the wrong PP they sent me...