Diagnose my clutch over the internet

[Plaz]

Originally Posted by Nick M3

My general recommendation is give it an extra 500 revs before engagement. Any solution involves a new clutch assembly, so who cares if you use it up a little faster?

Edit: And I agree that it's most likely that the flywheel is failing to operate correctly. Stupid dial mass crap.

Right, thanks, that's what I've been doing most of the time, almost subconsciously. And being more judicious in stop-and-go traffic to avoid as much as possible situations that will require extended slipping rather than full engagement immediately.

Kind of maddeningly, this morning it showed no symptoms at all, behaving perfectly without any special treatment. Not sure how that happens -- either it's broken or it's not, right?

[John V]

There might be some uneven clutch material deposits on either the pressure plate or the flywheel which could cause the juddering, which could cause the two flywheel masses to get out of sync. Just a guess. Clutches also grip better when they're warmed up, so if it was cold this morning, it might hide the problem.

If there's a single-mass solution for your car I'd probably choose to replace the clutch / FW with that, assuming you take the car in to get the clutch done. There is nothing magic about BMW clutches that requires any specialized labor. Any good indie shop should be able to handle it. It'll be expensive, though.

[Plaz]

Originally Posted by John V

There might be some uneven clutch material deposits on either the pressure plate or the flywheel which could cause the juddering, which could cause the two flywheel masses to get out of sync. Just a guess. Clutches also grip better when they're warmed up, so if it was cold this morning, it might hide the problem.

If there's a single-mass solution for your car I'd probably choose to replace the clutch / FW with that, assuming you take the car in to get the clutch done. There is nothing magic about BMW clutches that requires any specialized labor. Any good indie shop should be able to handle it. It'll be expensive, though.

That's an interesting thought (deposits). It was cold this morning, but the problem was pretty horrific at times over the winter, too. I wonder if doing some gratuitous clutch burning would help "mill" any such deposits off, or just make the problem worse.

Single mass is also an interesting thought, though with this car I'm especially hesitant to do anything not to OEM spec. I'm going to sell it at some point (not soon), and I have a feeling potential buyers for a high mileage 1M are going to be extra anal-retentive about absolutely everything. Even moreso if it goes up on BaT. (Have they even had a 1M yet?)

Good to know there's no special BMW clutch juice required. Thanks.

[Nick M3]

Originally Posted by Plaz

Right, thanks, that's what I've been doing most of the time, almost subconsciously. And being more judicious in stop-and-go traffic to avoid as much as possible situations that will require extended slipping rather than full engagement immediately.

Kind of maddeningly, this morning it showed no symptoms at all, behaving perfectly without any special treatment. Not sure how that happens -- either it's broken or it's not, right?

This is why I complain so much about too tall gearing.

[AF]

I can't comment on what could be the issue but in regards to using a dealership for replacement versus a shop I wanted to give you an issue I went through.

When I had that NSX a few years ago I had a shudder on the clutch at take off first gear as well and had the dealership replace the clutch which I paid for. The replacement clutch was if I recall a little better but had a shudder at take off as well ... the best part of having an Acura dealer do the work is there was a warranty and they ended up replacing the clutch again without any argument or questions. They also did multiple adjustments to it when I wasn't satisfied with the feel. Another benefit is they supplied a loaner car each time I took it in.

I don't know if a regular shop would have done this or not but I do know the dealerships never minds doing warranty work if there is an issue with their work being they get paid by the manufacturer.

[Plaz]

Sure, but I'm well out of warranty. And my guy does have loaners. (A couple of E46 325s)

[Nick M3]

Originally Posted by Plaz

Sure, but I'm well out of warranty. And my guy does have loaners. (A couple of E46 325s)

IIRC, dealerships also charge roughly twice as much for the job. The point that the dealer work/new parts are covered by some level of warranty is valid, though.

[jpgurl]

Originally Posted by Plaz

The most noticeable manifestation of the problem is when starting from a stop in 1st. As I engage the clutch and lift the pedal through the bite point, there's often (though not always) a good bit of "judder" for lack of a better term -- it almost feels as if it's not two parallel planes coming together. Then, almost every time, there's a delay from when I've come up fully through the bite point and when the whole mechanism feels as if it has locked... at which point there's a delayed (not super harsh, but present) "thud" as the whole system is finally working together properly. I have not had any problems or signs of unusual behavior on any other shifts -- only when launching.

The Mini has started doing this too. I have also started bumping up the revs at launch to try to avoid this. Guess I'm getting a new clutch soon.

[kognito]

Originally Posted by AF

I don't know if a regular shop would have done this or not but I do know the dealerships never minds doing warranty work if there is an issue with their work being they get paid by the manufacturer.

IMHO any Indie shop that stand behind their work isn't going to last long.

Edit: and Plaz already has a relationship with his shop in Sterling

[Nick M3]

Originally Posted by jpgurl

The Mini has started doing this too. I have also started bumping up the revs at launch to try to avoid this. Guess I'm getting a new clutch soon.

Or not. If you can live with / drive around the juddering, you could have tons of life left in the clutch. The dual mass springs seem to wear out a long time before the clutch disc itself does most of the time.