Schnell Gelb

2001 Boxster S
My flywheel measures 20mm play at the periphery.I found some mention of rebuilds. Here is a rebuild tools site. So someone out there rebuilds these flywheels??
Any referals/suggestions?

http://www.schaeffler.com/remotemedi...tool_de_en.pdf

Macster

Not sure what you mean by "play". What has play, exactly? By play I mean movement that is not due to the unit being loose or improperly mounted.

I've not come across any business that rebuilds these dual mass flywheels. I have to admit I haven't looked that hard.

If the unit is not reusable due to a bad dual mass feature or due to heat damage, excessive wear or cracks around the holes, missing teeth, etc. it is probably better in the long run to just install a new one.

Schnell Gelb

Thanks for your reply.
The 'play' is also refereed to as 'rock' in the Schaffer DMF tools link above.The Porsche TSB test is that the distance the flywheel will move is no more than 15mm.Mine is 20 between the white lines in the photo. The rest of the flywheel looks almost new-amazing quality of those LUK parts -pity about the DMF springs.

Schnell Gelb

Here is a link to the Sachs website that shows the inner mysteries of the dual mass flywheel.Very useful.
http://www.understeer.com/pdf/dualmass.pdf

Schnell Gelb

YES YOU CAN REBUILD IT -Enjoy!
http://www.oilburners.net/forums/sho...MF-is-possible

Macster

Reads like it could be rebuilt. However, I just did a search and got no hits of anyone who has rebuilt a Porsche DMF.

Admittedly not enough "evidence" to claim it can't be done.

But based on my search results it appears you would be breaking new ground, unless you have found a write up from someone who has rebuilt one.

Wonder where you would get new replacement parts? Porsche doesn't carry them I bet. I checked Pelican Parts web site and do not see any DMF internal parts offered.

Would you have to contact LUK?

Schnell Gelb

It is a big market opportunity to rebuild them -lots of US pickups use DMF.Lots of Internet chatter about conversion to a single mass flywheel.
Although mine has 20mm of total motion,it has no appreciable axially wear/wobble and does not rattle. It seems such a waste to just throw it out.

Macster

The motion or free play means the take up is not going to be as soft/smooth as it would be otherwise. Over time this free play will let the DMF hardware get pounded more and degrade the DMF feature further.

Additionally of a bigger concern, is this transmits this pounding, force, back to the engine. That is the DMF is unable to absorb/cushion shocks and the engine received these shocks.

In the DMF and the engine partnership the DMF is the sacrificial item. I'd rather replace the DMF every time I did the clutch rather than have the engine need attention. 'course, my car's clutch life has been exemplary, 280K miles and count ing, and that's easy for me to say.

However, my driving technique is not magical, just plain old manual transmission common sense. If someone is not getting good clutch mileage I would have to believe the problem was with the driver not the clutch and one should work on his driving technique to derive better clutch life.

You probably won't like to read this but if the DMF fails the range of motion test and if you are unable to rebuild it, my advice would be to replace the DMF.

I am also going to state I do not think a light weight flywheel or a flywheel with no DMF feature a viable alternative.

The DMF also serves in some capacity as a harmonic balancer and that is an important function. That a small number of owners have installed some other flywheel option and the engine or transmission has not suffered some obvious issue from this does not provide me with sufficient proof the DMF feature is without beneficial.

IOWs, I'm not qualified to advise you to go against Porsche and ignore its requirement to run a DMF. I can only point to the fact the car came with one from the factory, and the factory service/repair chapter on this subject requires a similar unit be installed if the current one is not serviceable.

Schnell Gelb

Macaster,
Thanks for your explanation.
I have read everything on DMF's from LUK,Sachs, Valeo ,other Forums.
Your version of the explanation is more convincing than the OEM's !
The reason is that you explain "why", not just a mindless rule like "every other clutch change" or 90,000 miles. It is the Engineer's curse -we crave logic .
I'll spend the money if it is a well informed ,rational decision. It is the ill-informed ones that bug me!
Price : for the benefit of others about to spend $500-800 on a DMF -check Ebay. I found a LUK DMF042 for $384.Others have mentioned a BMW interchange and I noticed a LUK DMF+pressure plate+clutch disc for $715. The Pelican "Super Kit" is $1400.O.k. if contains lots of essential small parts too but....
If I find a reliable Interchange number for the complete kit, I'll post it for others to discuss.
Thanks again for the explanation Macaster !

DennisAN

RockAuto sells a new LUK DMF for your car for $329. (DMF042) Why play around with rebuilds?

Schnell Gelb

Thanks Dennis.
Actually $338 with shipping but you make a good point. Got to be careful with Rock -if you order 3 items they often want to ship from 3 different locations (even if you select the minimize shipping option) and the total cost is alarming.Weird -they want less than $10 to ship this beast!
The rebuild idea is moot (for the Porsche at least -with GM yemv)-see links above. The mechanism is so simple that in theory it would be cheap to rebuild. LUK have moved on from DMF (for some applications ) to DFC - a cheaper and more compact design ,so I guess they have no incentive to enable rebuilding the DMF. The wear on the surface of the 'secondary flywheel' would limit rebuilds anyway.
The real trick would be to fit a DFC ? Especially since LUK/Schaffer claim it is an "upgrade" compared to the DMF
http://www.schaeffler-aftermarket.co...ywheels_aa.jsp
I am trying to get a quote from Pelican for a "Super Clutch" kit that includes the upgraded and according to Wayne Dempsey Cayman upgraded pressure plate+friction plate. So far I haven't had any luck there.
Just trying to use this as an upgrade opportunity and not just a routine maintenance issue.