Bertamus47

Hi,

My 04 boxster s with 54k miles is in the shop for the TuneRS DOF. The mechanic said the clutch is worn and has hot spots and recommends replacing it now. He also said he can move the flywheel 5 sprockets worth which he said indicates wear and also recommends replacing. Is it usually necessary to replace the flywheel as well? Car has been driven like a porsche but never raced or autocrossed. Thanks.

Barrett

Otto Mechanic

If your clutch wasn't worn to metal you shouldn't need to do anything more than resurface your flywheel. Any decent machine shop should be able to do that. Make sure they balance it too, you may as well have them balance the flywheel and pressure plate together.

Sorry, didn't read the "5 sprockets" part. The flywheel should move about 15 mm right and left then return to where it was when it's released. If it turns more than that (about a half inch) without any spring pressure the manual says to replace it. Not sure how that translates to "sprockets", the fellow probably meant "teeth" and I still can't guess how many mm that should be, but he should know that it can move more than 15mm, but not without at least some spring resistance.

It's supposed to be good for about 100K miles so at 57 that's a bit early. You may want to ask how much pressure he feels or get a second opinion since the the dual mass flywheels are sort of expensive. Usually the flywheel should get you through your first clutch replacement.

trendy996

I have a light weight flywheel from AASCO for sale. I either have a used one with 1500 miles or a brand new one. Pm me

Bertamus47

Ok thanks for the help. Yes sorry I meant to put teeth instead of sprockets. He said something about 2.5 teeth worth of play being normal but because mine had 5 it was out of spec and needs replacing. It does seem early for replacing but I'd like to avoid paying for labor to take the transmission out again in the near future.

Macster

Hard to over rule a tech who should know and is at the car and has the hardware in front of him.

If you trusted the tech enough to take the car to him you should trust him when he says the flywheel needs replacing.

Couple of things: "Hots spots" is rather vague. A while back, at around 120K miles, my Turbo was in for a new RMS. Of course the transmission was removed and of course the flywheel was exposed. It had quite a bit of discoloration -- bluing -- which comes from heat but the clutch had been working just fine and the disc showed no signs of measurable wear. (I measured the disc thickness myself with a depth micrometer.) The flywheel was reused along with all the clutch hardware (save the needle bearings of the clutch control shaft which were replaced) and the clutch and flywheel are just fine.

My point is any used flywheel is going to show these blue spots, aka hot spots. But have these hot spots turned into hard spots? One "test" you can try is to drag a hardened steel object across the face of the flywheel. When I did this "test" I'd use a metal scribe with a carbide tip. I didn't use much force but the idea was to see if in dragging the scribe across the flywheel one could feel a change in the flywheel material's hardness. If one felt the scribe point digging in a bit then sliding across another spot then digging in again this is a sign that enough heat had been created to generate hard spots in the flywheel's face. If severe enough this could render the flywheel in need of a resurfacing, possibly even replacement. But this is AFAIK a judgement call.

Generally speaking, if the clutch is just worn out, and has not failed due to excessive overheating from continued usage after slippage has been detected, or excessive overheating as could be the case say if someone got caught up in a horrible traffic back up and spent some time inching the car forward by slipping the clutch which resulted in overheating the clutch, and provided a visual inspection of the flywheel turns up no reasons to replace, the flywheel can be reused, provided the dual mass feature is ok.

The dual mass feature can fail or degrade and in some way wear out. There is a test to measure if this feature is working properly. I can't find this test in my references. I'm sure a web search would turn up a description of the test.

So provided the flywheel was not severely overheated, or suffered from excessive wear, or has other conditions (cracking?) that demands the unit be replaced, the flywheel can be reused.

Regarding wear: I came upon a Boxster at a dealer. The car was in for a new clutch. I forget how the subject came up but regarding the flywheel the tech said it was out for resurfacing. The clutch disc had worn enough the rivets were contacting the flywheel face. It was this contact, the grabby nature of the clutch's engagement, that prompted the owner to bring the car in. The tech assured me that the flywheel could be resurfaced and be just fine to reuse. (I'm sure he had already confirmed the flywheel was ok in all other areas, including that the dual mass feature was working ok.)

Now you have to consider this: If you overrule the tech and the clutch action proves to be unacceptable either right after the job or sometime in the near future and you have to have this job redone to replace the flywheel, possibly even other clutch hardware, well, you have to be prepared to accept that responsibility.

(As an aside, I would not replace the dual mass flywheel with a light weight flywheel. The dual mass flywheel is pretty light and offers a dampening benefit that lessens torsional stress on the crankshaft. It also helps insulate the engine and transmission from shock of sloppy clutch work.)

Schnell Gelb

Here is the inspection procedure for the DMF

Bertamus47

Thanks alot for the helpful tips and videos. He does seem knowledgeable and trustworthy but I wanted to get a second opinion, especially since he said that most people replace the flywheel when they replace the clutch(I had never heard that before). Prices seem kinda steep, clutch is $800 and flywheel is $1000 with installation, so the info will be helpful when he shows me in person.

Otto Mechanic

Both quotes are reasonable since they include labor but without knowing exactly who's making the parts and what parts are included I couldn't say for sure, for example Pelican charges $1031 + shipping for a "Genuine Porsche" flywheel alone. $800 for an installed clutch is surprisingly good as long as it's an OEM part and it includes all the other stuff usually replaced during a clutch job.

To get an idea of what "other stuff" means, check out the parts list at http://www.pelicanparts.com/catalog/...TCLUTC_pg1.htm

Macster

From a shop's point of view replacing the flywheel makes sense. Obviously all the hardware from the flywheel to the release bearing and everything in between has to work just so for the driver to have a long and trouble free clutch experience.

From the shop's point of view, nothing is worse than having a customer bring back a car with a clutch problem after having just picked up the car a short time before.

So, to be "safe" a shop would prefer to replace the flywheel rather than risk reusing the old one even if it appears to be in good shape.

I still can't really overrule the shop/tech in this matter. While I have no problem in sometimes overruling a tech regarding my cars, when I do I understand if I'm wrong I could be facing an extra expense. So when I overrule the tech I do so with this in mind and while with this in mind I'm still comfortable with my decision.

My 2nd hand info is that the prices quoted don't seem to be out of line. Thus I doubt the tech -- I never really thought this was the case anyhow -- is recommending the flywheel be replaced to pad the bill.

My opinion is he is just advising you a course of action that promises to be the least risky that you will bring the car back with a subsequent problem with the clutch.

Bertamus47

They are both OEM he said. I never suspected him of trying to squeeze me for money or anything, I just meant that because the parts are expensive no matter where you buy them I wanted to be able to make a good judgment call. He showed me the flywheel and clutch today and it did in fact have excessive play. Thanks again.

Otto Mechanic

+1 on this. If the shop were trying to pull a fast one they wouldn't have offered such an exceptionally good deal. $1800 for a clutch/flywheel really isn't bad at all.

Of course, now you have me wondering what the catch is ...

mikefocke

to recommend the IMS product and not to know what else should be done while he is in there?

Once you are in there, it is the perfect opportunity to do the RMS, IMS, AOS, clutch, flywheel and any bearing, bolt or other small part associated.

Now this all assumes you don't crash the car a month later, or one of the other 27 failure modes don't take out the engine.

Trying to figure out how much preventative maintenance to put into a car is greek to me. I guarantee you I've done it wrong more times than right. Like my last Boxster sold after $1,500 in unnecessary updates and improvements within the 3 months before the sale. OTOH, I could represent the car as being in great shape when I sold it. A good conscience allows sleep. (Oddly enough, this week I heard from it's current owner. Two years later at ~80k it is still on the road on the original single row IMS. )

bspank

What year /engine is the flywheel for?

Schnell Gelb

Before getting too enthusiastic about replacing a DMF flywheel with a LWF ,suggest a little searching here on Rennlist. Some experts(not me!) advise against it.
With no DMF and no harmonic balancer(never fitted) how else are you achieving dampening of the harmonic/dynamic imbalance of the engine ?
Answer - you are not. And that is the problem. The effect of this is not instant catastrophic failure. But it may shorten the life of the engine.
That said, it is a tempting mod to remove that huge weight hanging off the rear of the engine.
When I rebuilt my engine I had both the crankshaft and the new DMF balanced. It was surprising how much adjustment was required to the DMF.YEMV

gstreev

I'm debating this myself, for my 03 S, a LUK DMF042 flywheel is $350, a LUK 20-018 Clutch kit (Sachs Makes it) is under $300. I was told that the Dual Mass Flywheel should never be resurfaced.