New Flywheel and Clutch

[craigzaller]

It has been a while since I started a new post.
I need some advice. I am not sure if my clutch is failing prematurely (I have 21k miles on my Z8) or what, but it seems in general that I can't launch off the line. I am not a 16 year old that often takes off at a light but I had the only Z8 at the first annual east coast Bimmerfest yesterday in Aberdeen, MD (which was insane) and many of the young kids egged me on to launch off the line when I left which made me realize the issue. I just couldn't engage the clutch to launch and I know how to drive.......In any event, I didn't see any old threads about any recommended replacement clutch, only threads about them wearing early.
Can the clutch be adjusted, or does it likely need replacement?
Assuming that I need a new clutch, should I just put a new OEM one back in the car? or are there better replacements out there for street use (I do not track the car).

And, I know that if I do need a new clutch that I may as well upgrade the flywheel while I am in the area........ In that regard I only seemed to find one old thread that ended in 2008 regarding recommending either Dinan's or UUC Motorwerks flywheel. That was 3 years ago.
What feedback has there been since then?
What flywheels do any of you recommend now?

And/or recommendations for any clutch/flywheel combination packages to assist with slippage and getting off the line better?

Thanks in advance for everyones feedback.

Craig.

[craigzaller]

I was just reading about removing the CDV if you upgrade the flywheel.
Exactly what is the CDV and are there any negatives to removing the CDV whatever that is?
Craig.

[macfly]

This link will tell you all you need to know - http://www.bmwz8.us/vbb/showthread.php?t=133

[craigzaller]

Thanks as usual Andrew.
Craig.

[craigzaller]

Andrew,
ps: any thoughts on the flywheel and clutch issue?
Craig.

[macfly]

Well some of the earlier cars did wear through their clutches quite quickly, and this was generally attributed to being the CDV focusing the wear in the clutch to protect the drive train from any warranty claims.

Overall it should not have worn at that mileage, and you may find replacing the CDV alone will cure the problem. However putting in a lighter flywheel and a new clutch can't be a bad thing to do, but it may be a lot of expense when just replacing (or drilling out) the CDV will do.

[craigzaller]

Thanks again Andrew.
And, I assume from what I have read this a.m that I should contact Zeckhouse racing in NJ about this?
Craig

[macfly]

Yes, for sure, first call would be to them.

[thegunguy]

Even without the CDV, our car and the M5 seem go through the friction components more quickly than most vehicles, and your car is pretty consistent with the experience of many.

As far as what to do, you won't need a new clutch. It just needs to be serviced, but it is good to consider other options as you could be in the same situation at 40k. When mine goes, I'm planning on going with the 850CSi clutch/flywheel setup from UUC. It seems to be a great alternative with increased surface area and reduced weight, all while using common service parts available from BMW. If you want to keep the original clutch, the Dinan flywheel would be good option, but again you're back in to the possibility of an early service. That all being said, even if the Z8 clutch had to be serviced every 10k miles, with the annual mileage most of us put on our cars, it's not much of an inconvenience to do.

[thegunguy]

Also, you should remove the CDV in ALL cars, not just if you upgrade the clutch. It's the cause of most clutch wear.

[craigzaller]

So, if I can summarize everyone's advice.
Call Zeckhouse Racing and remove the stock CDV no matter what I do with the clutch and flywheel.
Then, if I want to replace the flywheel to get even more launch and acceleration, I should go with the UCC set up and new clutch at the same time?
The UCC set up is better than the stock clutch and the Dinan flywheel?
Am I correct?
Please confirm and then I will be set with my plan of attack.
Thank you all for your advice.
This site has always been great for any issues that I have had with my toy!
This issue being no exception.
Craig.

[macfly]

I haven't tried those upgrades so can't comment on them, but lighter is always better, so they sound good. However replacing the clutch is a big job, but replacing the CDV isn't.

[Z8Mania]

Yes remove CDV ASAP.

Im with you- Ive had M cars with 60k plus miles without having to replace the clutch. On my Z8 I had to replace the clutch in 18,000 miles. The CDV was definitely the cause.

As for launching the car, you may wish to investigate a limited slip differential.

[Norcal]

Not sure the lightened flywheel helps with "Launch", but it will rev quicker and be generally more responsive. The after market pressure plate will likely have better grip (higher pressure) which should help launch. The CDV definitely causes slip during a hard launch.

[DZeckhausen]

I was just reading about removing the CDV if you upgrade the flywheel.
Exactly what is the CDV and are there any negatives to removing the CDV whatever that is?
Craig.
This link will tell you everything you need to know about the evil Clutch Delay Valve (CDV): http://www.zeckhausen.com/CDV.htm

You can remove your valve and discard it. Requires slight bending of the steel hydraulic line leading to your clutch slave cylinder, to make sure the threads of the fittings line up properly. DO NOT cross thread these! Alternatively, you can purchase a modified valve from us. Then it just replaces the old valve - no bending of lines required. Either method is functionally equivalent.

[craigzaller]

Dave,
I have been trying to call you all morning and no one seems to be able to get me to you. I keep getting transferred around. My cell is 410 707-1831.
Can you please call me.
Thank you.
Craig.

[thegunguy]

I have a correction my thoughts here. I had gotten it in my memory that the M5, which was delivered sans-CDV, had lowish clutch life of say 50k. I think I was basing this on some reading that I had done many years ago on modified cars, which quickly exceed the OE clutch. Going back over posts form the sister-board, the E39 clutch is holding up very well in unmodified cars. So, my thoughts on experiencing the problem again, don't seem to hold up.

So, my thoughts would be:
1. Remove the CDV - period - and replace it with one of the modified units from Zeckhausen.
2. Without the CDV, a serviced clutch could potentially last to the 100k mark, which is quite far away for most Z8s.
3. If you want a more dynamic rev/acceleration profile, consider the products from Dinan and UUC.
4. If you're upping the power in your car, you really need to look at UUC. They have many great options.

That being said, I'm going to go with the UUC at some point soon with my stock motor. I discovered a while back that the shop that originally swapped my CDV actually didn't, and I put about 7k on the car with the silly value before I did the change myself. As such, my car will slip if I shift hard, which isn't very often, but I'd like to not have to worry about babying it. Sure, the stock stuff is fine, but I just like the idea of the UUC 850 setup. It seems like what the car was meant to have, while staying true to the BMW parts bin. The only downside seems to be the single-mass flywheel, which can introduce a slight external noise at idle, but everything I've read shows that it is very minor and can be eliminated with proper fluids. Besides, the S62 already chatters quite a bit at idle, even when warm. Another virtually unnoticeable tick isn't such a big deal for a more rev-happy and stronger clutch setup.

[DZeckhausen]

Dave,
I have been trying to call you all morning and no one seems to be able to get me to you. I keep getting transferred around. My cell is 410 707-1831.
Can you please call me.
Thank you.
Craig.

I'm tied up today. Joe can help you - x298

[Z8Mania]

Rifle, many E39 M5 owners fried their clutches in a few thousand miles due to the power of the motor and the weight of the car and the fact that the clutch is that from the 528! :p The E39 M5 was the last M car I am aware of that came sans CDV. As the Z8 is not a M car, we got stuck with the dreaded CDV. I had something like 45k on my first E39 M5 with no clutch issues at all. Thats why I was shocked when my clutch was gone in the Z8 in under 18k miles. And I learned. I met Dave Z and he did the CDV remove for me- highly recommend and Dave is a real nice guy and general automotive enthusiast.

[thegunguy]

Aye. Thus my preference for the UUC 850. I like clutches that can take a little more abuse, even if I don't abuse them. Should have better engagement feel too.

[craigzaller]

Thanks everyone for your advice last weekend and over the past week.
I am have been slammed at work all week and did not have a chance to get back on the board.
In any event, here is where we are and I would love any final feedback.
First, for those that don't recall my car - I bought it last summer with 19k miles on it from one of the other members of this board - named Kevin Magenis, in CO.
I had it shipped to me in MD and installed every single Dinan part possible (like those on my dinan s2 e39m5 (2001) (my daily driver) but the lightweight flywheel.
I also installed the performance package and the quife lsd, and changed the gearing as well. So, the car roars... with about 460 hp and 415 lb/tq.

This is the last issue to address.
So, I already spoke to Zechhausen and already have his modified CDV in my hands (and some stainless steel break lines and dustless brake pads) (all of which will be installed next week)
So, the only issue left is the clutch/flywheel and it apears that I am down to the Dinan v. UCC issue. I spoke with UCC at length and I spoke to Dinan as well.
I hear great things about both but my speed shop guy recommends me going with the Dinan flywheel and either keep the stock clutch or use a "Sachs" clutch.
Or, do the Ucc set up but he thinks I won't be as happy.
He is a dealer for both UCC and Dinan and says he will actually make less money on the Dinan set up but that he says he thinks I will be happier with that set up. He says that he has had some issues with UCC (not with this clutch/flyweel set up thogh) in general and thinks that Dinan simply has better engineering and that if their flywheel is 7 lbs lighter than stock that there is reason for that etc......

Bottom line is that I am torn and unfortunately can't feel the difference in either option without pulling the trigger.

I love the feedback on this board about the UCC set up as many of your are praising it, but some of you responded about noises at idle, something my speed guy warned me about as well. ie: if the flywheel is off by x millimeters it will rattle....

re: Dinan - I already have the car set up with all of their parts and just adding the flywheel seems logical (which flywheel is on my m5). And, if I did the Dinan flywheel, do I keep the stock clutch or use the Sachs clutch that he is recommending? or do any of you have another recommended clutch to use with the Dinan flywheel?

I am torn as you can see.

thoughts are appreciated.

Thanks.
Craig.

[macfly]

I'd go Dinan over UUC because they build the Grand Am race motors out of our S62, and have put two of those in Z8's with great effect.

[craigzaller]

Thanks Andrew,
OK, Dinan flywheel - thoughts on the the clutch then?
keep stock or go with the Sachs one my speed shop is recommending? or others?
Craig.

[macfly]

Sachs, or more to the point ask Dinan what they used in the Grand Am - Z8's.

[Z8Mania]

Agree- and the lighter flywheel will make shifting faster more rewarding but it will also make the car feel a bit more sports car and less GT. Craig I drove a fully Dinaned E39 M5 and IMHO it was a better drive than any M5 from any era I've ever driven.

[craigzaller]

Agreed on my daily driver. It is a beast!
Thanks for the tips.
Craig.

[thegunguy]

Having driven the Dinan supercharged S3 M5 (which requires a different clutch) and S2 Z8 extensively at the track, I have massive respect for their capabilities and DD civility, which is where I see the value in Dinan's often argued overly-premium pricing. For the extra cost, you get near world-beating performance that's still usable every day.

On the clutch, I doubt that Dinan uses the dual-mass flywheel and OE clutch in the Grand Am cars or in the even more powerful two specially built S62s for the street (are we calling this the GM engine? :)) Especially on the GM engine, I would think that the power would quickly overwhelm the dimensions of the clutch.

I was under the assumption that the original clutch was already Sachs product, but I could be wrong with this. The caution I have on your car, or any heavily modified car, is the clutch is already a weak point, even without the CDV. As Z8Mania mentioned, it's a donated system from the standard 5 series that has much less torque. The thing I start to get concerned with is the physical size of the OE clutch. It's rather small, and seems to just barely cover the output of the standard S62 (admitting that it can be improved with upgrading the friction components, etc.). Once you start loading on big mods, like the S2, you're walking a fine line. I'm actually surprised this isn't something that Dinan doesn't suggest/require like they do with the S3, but they certainly know way more than I do on this. This is why I prefer the UUC. It has more surface area. So, even before going for the crazy kevlar, etc., it can take more abuse. I've read of many S2 M5s running around with the standard clutch doing just fine, but it just strikes me as the weak part of the system.

As far as the UUC and noise, this was an issue early on, but I haven't heard it be an issue any longer. Even when it was an issue, we're talking a VERY slight chatter at idle. With the already clanky/ticky S62 and aftermarket exhausts, I see it to be a non-issue. As Dave Pledger can likely attest, UUC virtually resolved the issue with fluids. I also believe Dieter's 500+hp Nowak monster uses a UUC setup. I had a chance to drive this amazing machine in Italy during the Villa d'Este, and it is turbine smooth in every way. No harshness, no noise, nothing but amazing refined power.

[briandilley]

Had to get a new clutch and all at 11K. Seems like the torque on the motor is just a little bit too much for the clutch for too many miles. But I got the whole clutch and flywheel, with the bulletin thanks to this forum, installed, the 12K BMW maintenance conducted, new oil, radiator flush, AC drain tube cleared, and the micro filters replaced all for $3100 at the BMW dealership. Seemed like a fair price for all the work, and they kept the clutch replacement time to 10 hours.

[briandilley]

Oh, I forgot, I also got a new serpentine belt installed as the original belt was squeaking a little bit, was in good shape, but I thought an ounce of prevention was worth it. Car run like a spirited Kentucky thoroughbred again. Price was still $3100 for all this work.

[craigzaller]

Hi Brian and eveyone,
Thanks again for all of the feedback.
I made a decision and ordered the parts.
I am removing the cdv, going with the Dinan flywheel and the Sachs clutch.
Fingers crossed.
I will give you all an update in about 2 weeks when I get everything installed.
Going on vacation for a week in an hour.
Craig.

ps: Brian - By the way, just in case you did not realize I am the guy with the other Z8 that you met at the coffee and car event a month or so back at Maple Lawn.
I can't tell from your post, but what clutch did you put back in your car? the stock one?

[briandilley]

Hey Craig, hope all is well. I went with the BMW parts, the Dinan flywheel was available, but the mechanics couldn't recommend a clutch to go with it, so I opted to stay safe. The car runs great though and with the CDV removed a couple of years ago, it has plenty of pick up.

[craigzaller]

I have now had the CDV removed, installed the Dinan Flywheel and had a Sachs clutch installed. I already had all of the other Dinan parts installed.
These were my final modifications to my toy.
Needless to say the car was already insanely fast but now the car is just plain and simple stupid fast - especially off the line now.
It just takes off. What a toy!!!
Craig Z.

[macfly]

Good for you, enjoy it to the fullest!! :-)

[ZMates]

What Sachs clutch is this?

Thanks, John

[thegunguy]

I'd like to know that too, because I still believe that OE clutch is Sachs. Also, I thought the dual-mass flywheel by Dinan was designed to work with the OE clutch dimensions. So, you "shouldn't" need to change it if your'e making the change, although I'd still recommend upgrading it as the original clutch is from the six cylinder five series.

[zed8]

Hi all,

My clutch is slipping as well. Be fore replacing it I would consider servicing it. What do you mean by servicing the clutch and/or pressure plate?

[thegunguy]

It's sort of similar to brakes where you replace the pad (the friction component that wears). Over time the the friction surface of the clutch wears down. Assuming all else is good, you just replace the fiction disc (the pads from brakes).

There may be other servicing that is necessary, bearings, etc., but the clutch mechanism is designed to be serviceable for the life of the car.

If you haven't already, remove the CDV.

I also suggest that anyone servicing the clutch considering upgrading it since even on an unmodified car, these things have a very short life (comparatively) since it was design for the six cylinder engine, which has much less torque.

[zed8]

Okay, I got it. What you think about this set? It is very cheap.

http://www.ebay.com/itm/BMW-E39-M5-Z8-Disc-Pressure-Plate-Release-Bearing-Clutch-Kit-OEM-/170715900792?pt=Motors_Car_Truck_Parts_Accessories&hash=item27bf75eb78&vxp=mtr#ht_1539wt_1303

[thegunguy]

The standard parts from BMW are about the same price.

Before ordering anything, I'd take it to your service guy to let them look it over. While slipping is usually just the friction component, a good once-over on the drivetrain is never a bad idea.