[tscdennab]

Originally Posted by cyniclaus

I really don't know what prep was done to the flywheel...probably none. The mechanic did state that it looked fine. Of course, as vague as that expression is, it could mean anything or even nothing at all. They did say if it continues to bring the car back, but I'm sure they're not going to want to spend several hours of shop time just to do checks but, if they failed to properly inspect when the job was done, then that's a different story

I don't question the mechanic's skills even one bit, but really, what do you expect a mechanic to say about the flywheel if they spend like 2 hours to disassemble the exhaust, driveshaft, drop the gearbox, etc. ? I mean, do you expect him to say "the flywheel needs resurfacing ?". If he would say this, there would have to be a way to either find a nearby shop to resurface a dual-mass flywheel on the spot with no prior appointment, or obtain a new N54 flywheel on the spot, or put everything back and send you home while charging you 60-70% of the planned labor cost, or hold your car in the shop disassembled until the flywheel is either resurfaced or replaced. All of these scenarios are impossible and neither you or the mechanic expect that to happen so unless the flywheel is falling apart, he has no choice but tell you that the flywheel can be reused. You really have to plan ahead on this, there is no way to solve a "flywheel has hot spots" scenario on the spot, and the mechanic knows this.

Just my opinion.

[cyniclaus]

Originally Posted by tscdennab

I don't question the mechanic's skills even one bit, but really, what do you expect a mechanic to say about the flywheel if they spend like 2 hours to disassemble the exhaust, driveshaft, drop the gearbox, etc. ? I mean, do you expect him to say "the flywheel needs resurfacing ?". If he would say this, there would have to be a way to either find a nearby shop to resurface a dual-mass flywheel on the spot with no prior appointment, or obtain a new N54 flywheel on the spot, or put everything back and send you home while charging you 60-70% of the planned labor cost, or hold your car in the shop disassembled until the flywheel is either resurfaced or replaced. All of these scenarios are impossible and neither you or the mechanic expect that to happen so unless the flywheel is falling apart, he has no choice but tell you that the flywheel can be reused. You really have to plan ahead on this, there is no way to solve a "flywheel has hot spots" scenario on the spot, and the mechanic knows this.

Just my opinion.

That's a very valid point, and it had occured to me even before I got the work done, which is why I was looking for a full service shop that could resurface flywheels in-house if need be. I found one, but they wanted $200 more than the BMW specialist and had never worked on a E9X before. Here's what is on ACT's FAQ (I'm thinking of calling their tech dept to see if my chatter is within the norm or cause for alarm):

Q: What could cause clutch chatter?

A: Chatter is when the car shudders as the clutch is being engaged. Possible cause may be as follows: Flywheel has excessive run-out. Flywheel was not resurfaced or improperly resurfaced before the new clutch was installed. Damaged or excessively worn CV joints. Bad U-Joints in drive shaft or U-Joints misaligned. Excessive backlash in differential. Excessive driveline angle. Bad leaf springs, bushings or mounts. The use of an aggressive clutch disc designed for racing. Defective pressure plate and/or disc. Disc has inadequate Marcel (Not enough cushion between the friction facing.). Oil or grease contamination on clutch facings. Worn or damaged clutch linkage. Bent pressure plate assembly and/or disc. Improperly tuned engine. Worn or damaged engine mounts or transmission mounts. If you have any further questions, Please call (661) 940-7555 and ask for the tech department.


Q: Is flywheel resurfacing necessary before installing a new clutch?

A: A smooth, flat flywheel surface is essential for proper clutch operation. Flywheels are subject to heat, scoring and warping during use. If upon careful inspection there are signs of scoring, heat damage or warpage the flywheel should be resurfaced or replaced to assure good clutch performance. Resurfacing should be done on a flywheel-grinding machine only. Refer to your factory service manual or ACT information for resurfacing specifications (Flat, Step, Etc.). WARNING: IF YOUR FLYWHEEL SHOWS ANY SIGNS OF CRACKING, REPLACE IT! Never roughen the flywheel clutch surface with sanding as this reduces clutch life. The surfaces are designed to rub against each other (Producing Friction), not tear into each other (causing abrasion). If you have any further questions, please call (661) 940-7555 and ask for the tech department.

[cyniclaus]

So, I called ACT tech department and they said that the shuddering is not uncommon during break-in as the surfaces achieve a mating. He said to go another couple hundred miles and it should lessen as the clutch breaks in, otherwise call them back. He didn't even ask about the flywheel. Guess I'll report back in a couple of weeks or so.

[Jeff@TopGearSolutions]

Sometimes they assume you've resurfaced or have a new flywheel. It's worth mentioning that anyone purchasing any new clutch should think about a new flywheel or resurfacing. It's worth the investment IMO. If one's clutch as already started slipping there is a high probability that the flywheel has been hot spotted.

[cyniclaus]

Originally Posted by Jeff@topgearsolutions

Sometimes they assume you've resurfaced or have a new flywheel. It's worth mentioning that anyone purchasing any new clutch should think about a new flywheel or resurfacing. It's worth the investment IMO. If one's clutch as already started slipping there is a high probability that the flywheel has been hot spotted.

Yes, shame though that a new OEM flywheel costs close to a grand and, if you ask BMW and a lot of shops, our flywheel cannot be resurfaced safely (though many report having done it to no perceived detriment)

My issue was that a shop is not going to put your car up, take the flywheel out for you, and then wait a couple of days while you get it resurfaced. Someone needs to start a resurfacing by mail business where you can order a resurfaced flywheel with a core charge that is refunded when you send your old one back.

[Kris 335i]

Originally Posted by cyniclaus

Yes, shame though that a new OEM flywheel costs close to a grand and, if you ask BMW and a lot of shops, our flywheel cannot be resurfaced safely (though many report having done it to no perceived detriment)

My issue was that a shop is not going to put your car up, take the flywheel out for you, and then wait a couple of days while you get it resurfaced. Someone needs to start a resurfacing by mail business where you can order a resurfaced flywheel with a core charge that is refunded when you send your old one back.

It shouldn't take that long to resurface the fly wheel. I thought it was standard practice to resurface a flywheel whenever replacing your clutch. I would question a mechanic that would say otherwise...

[cyniclaus]

Originally Posted by Kris 335i

It shouldn't take that long to resurface the fly wheel. I thought it was standard practice to resurface a flywheel whenever replacing your clutch. I would question a mechanic that would say otherwise...

The problem I ran into is that many places wouldn't do the job because BMW says not to and they didn't want the liability

[Carl Morris]

Originally Posted by Justin@ADVAN Performance

Hi Gents,

my OS Giken "TR2CD" twin-plate has arrived from Japan.

However my 10 kg "Single Mass Steel" flywheel is yet to be sold.

Would someone like to turn that frown upside down?

Seriously guys I will post up some pics of the OS 215 mm twin-plate basket soon.

It certainly is a sexy looking bit of kit, I just have to get "Ross" to machine up a suitable flywheel, then in she goes.

Cheers,

JD.

Just wanted to bring this back from the dead and find out if anybody had any new information on what they think is the ideal clutch.

At the dragstrip last Friday my stock clutch failed to hook up off the line at 5000rpm and full throttle, so it looks like I'll be needing to do it by next spring.

JD, if you have additional/new info on the OS Giken that you talked about in this thread I'd be interested to hear it.

[Justin@ADVAN Performance]

Originally Posted by Carl Morris

Just wanted to bring this back from the dead and find out if anybody had any new information on what they think is the ideal clutch.

At the dragstrip last Friday my stock clutch failed to hook up off the line at 5000rpm and full throttle, so it looks like I'll be needing to do it by next spring.

JD, if you have additional/new info on the OS Giken that you talked about in this thread I'd be interested to hear it.

Hey Carl,

the OS Giken twin-plate clutch is done and has been ready to rock for some time now.

However as tends to happen with shop cars, their projects are put aside to make way for regular customers, so we can pay the bills in these tough times.

That being said the OS unit and a bunch of other suspension goodies will be going into my 1'er shortly.

Here are some pics of the custom flywheel we made and the completed clutch assembly.

Cheers,

JD.

[cyniclaus]

I'm finally getting my Clutchmasters FX850 twin disc kevlar/ceramic put in this weekend. I'll let everyone know how it works out

[Justin@ADVAN Performance]

A bit off topic of course,

but here is a pic of the "suspension goodies" I mentioned + another look at the beautifully anodised OS twin-plate top-hat and "basket".

Cheers.

[nitehawk]

Originally Posted by Justin@ADVAN Performance

A bit off topic of course,

but here is a pic of the "suspension goodies" I mentioned + another look at the beautifully anodised OS twin-plate top-hat and "basket".

Cheers.

Wow, solid subframe bushings, I take it this is going into a dedicated track car?
And where's the third Megan Racing arm (Camber link)?

[Carl Morris]

Originally Posted by cyniclaus

I'm finally getting my Clutchmasters FX850 twin disc kevlar/ceramic put in this weekend. I'll let everyone know how it works out

I'm curious about that because when I was on their site and searched for 335xi parts it didn't show their twin disk as available for my car.

[Carl Morris]

I like the Advan pictures...will there be an unsprung hub version?

[Justin@ADVAN Performance]

Originally Posted by nitehawk

Wow, solid subframe bushings, I take it this is going into a dedicated track car?
And where's the third Megan Racing arm (Camber link)?

Yep,

solid indeed, haha.

The rear end squirms and squirrels around under WOT in 3rd and 4th gear. There is not as much squirm in 2nd gear, as the tyres are beyond their grip limit.

I previously installed M3 rear subframe bushes when doing a Drexler LSD conversion, but there was still deflection with those rubber bushes.

Of course I had not done the toe control arms, trailing arms or lower camber links at that stage either, so perhaps the billet aluminium bushes may be overkill. But whilst the rear subframe was out again, I just wanted to get the rear end sorted once and for all, so the car tracks straight under WOT.

It ain't a dedicated track car, but it's rarely driven outside of the weekends on the street.

The M3 lower camber links require the correct lower shock mount, which thankfully I have courtesy of the BC-Racing double adjustable coilovers.

Cheers,

JD.

[cyniclaus]

Originally Posted by Carl Morris

I'm curious about that because when I was on their site and searched for 335xi parts it didn't show their twin disk as available for my car.

I became interested in the clutch after reading Former_Boosted_IS' excellent review. He hasn't had any problems in the years he's had it, and that includes his current 650 RWHP setup. Since I have AWD and have meth & RBs in my future, I wanted to get the best non-feramic clutch possible without breaking the bank

They don't seem to market this clutch very aggressively for the 335... most vendors don't offer it on their sites or, if they do, they don't show it being compatible with our cars.

If you call CM, they will sell it to you directly. FB_IS recommended I call Stett Performance, who is an authorized vendor for CM, and they came through with a great price.

[Carl Morris]

Thanks for the link, that's definitely applicable for me.

[Justin@ADVAN Performance]

Originally Posted by Carl Morris

I like the Advan pictures...will there be an unsprung hub version?

Thanks Carl, the OS multi-plate clutches are indeed a thing of beauty.

As good as our chromoly steel flywheel is, I would of loved to been able to purchase an OS Giken LWFW too, but a one-off unit would have cost me 2-3 times, what our unit costs to manufacture.

I am not sure why you would want an "unsprung hub version".

The dampening of the friciton plates is a good thing indeed, when you move away from the dual-mass flywheel.

It should reduce some of the gear chatter/rattle at idle induced by the single-mass flywheel, the sprung clutch plates will also allow for smoother clutch engagement and minimise shudder associated with hill starts etc.

I am not about to get into a discussion as to which is the better multi-plate clutch for the N54 application, OS or CM. But if you do the research online and read reviews from high horsepower GTR Skyline and Supra owners, the OS "TR2CD" twin-plate clutch has proven itself to be very reliable for 1/4 mile use.

Here are a few pics of a "R3C" triple-plate clutch assembly, not as streetable as the sprung hub/lighter pressure plate unit I have opted for, but the "R3C" has proven to be super reliable at the drag strip, in heavy arse and very high horsepower R34's with AWD grip.

Cheers,

JD.

[Carl Morris]

Originally Posted by Justin@ADVAN Performance

I am not sure why you would want an "unsprung hub version".

I've been through a lot of clutches and while the ACT unsprung race disk did allow a little extra noise and vibration into the cabin it was very nice for driving. It never chattered even when it got hot and the friction got very high. The only other really high friction disk I ever used (an early feramic...yes, I ended up welding it to the flywheel) was a sprung hub and chattered like crazy if you tried to use a normal slipping street engagement.

Previously I had been going through ACT street disks every year or two, and that race disk lasted for several years. So I was so happy with it I tend that direction if given a choice.

[Justin@ADVAN Performance]

Originally Posted by Carl Morris

I've been through a lot of clutches and while the ACT unsprung race disk did allow a little extra noise and vibration into the cabin it was very nice for driving. It never chattered even when it got hot and the friction got very high. The only other really high friction disk I ever used (an early feramic...yes, I ended up welding it to the flywheel) was a sprung hub and chattered like crazy if you tried to use a normal slipping street engagement.

Previously I had been going through ACT street disks every year or two, and that race disk lasted for several years. So I was so happy with it I tend that direction if given a choice.

I think your choice of the word "chatter" is equivalent to my use of the word "shudder", if you know what I mean.

Clutch "shudder" is largely dependant upon the friction material used and whether or not it's a full face clutch or a segmented puck clutch.

I have used 3 different clutches in conjunction with our single-mass steel (non-dampened) flywheel and ACT's "Heavy Duty" pressure plate, the factory BMW OE clutch, an ACT "Street" clutch and a HPF "Feramic" Stage 2 clutch.

All 3 clutches had unsprung friction plates and they all exhibited a similar amount of gear "chatter" or "rattle" at idle and on partial throttle between 1,750 and 2,500 rpm.

As you would expect there was no discernible clutch "shudder" when using the factory friction plate, a very small amount with the ACT "Street" plate and the HPF "Feramic" exhibited a discernible increase in clutch shudder. However that could be smoothed out a bit, by slipping the clutch at it's engagement point and using a higher rpm on take off.

For the record, I also managed to weld the "Feramic" face clutch to the flywheel, not once but twice, grrr!

The second episode required the use of a cold chisel to pry the friction plate away from the flywheel surface, it was there to stay.

[guidance]

Originally Posted by Carl Morris

The only other really high friction disk I ever used (an early feramic...yes, I ended up welding it to the flywheel) was a sprung hub and chattered like crazy if you tried to use a normal slipping street engagement.

Just a few questions on the welded Feramic.
Who made the clutch?
What was their response (technical & financial)?
This did weld in your 335, right?

[Carl Morris]

It was an early prototype disk for a Mitsubishi clutch about 10 years ago. I don't remember who made it. I think they refunded my money for the disk and the technical response was..."hmmm, didn't expect that". I was able to reuse the almost new ACT pressure plate and flywheel, and just accepted the cost of installing another disk and cleaning off the flywheel as part of being on the leading edge of development. At the time I was the first person I'd ever heard of doing it, but once I went public with the info it turned out I wasn't the very first.