Symptoms of a worn clutch
08-19-2011, 02:40 PM
#16
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Many flywheels have a replaceable insert that can be machined to orginal flatness once then it has to be replaced. The dual mass flywheels used on Porsches, Audis, etc. can be machined too but it requires a special set up to complete the machining that not many shops are prepared to do. Consequently, most repair shops simply replace these flywheels.
Hope this helps.
08-19-2011, 09:26 PM
#17
Race Director
At a stop sign, I rev up the engine slightly and by 4 mph, have the clutch fully disengaged. THEN, and only then do I accelerate with the accelerator pedal. These people who drop the clutch are simply adding to their maintenance costs by that action.
it's almost like ballet, with your feet. You give the engine just enough gas to keep it from stalling out, while simultaneously letting out the clutch. Then, with the clutch pedal out you can start to hammer it.
What will burn up a clutch is giving it a lot of gas (engine speeding up) while the transmission and the wheels are still going slow. The intersection of those two different speeds has to be sorted out by the clutch, and it will wear when you do that, by essentially slipping it.
When I was a kid, buying my first Porsche, I was going through clutches a lot--I had no idea what was going on inside there. I went to the repair shop and watched to see the interaction between the flywheel of the engine and the clutch plate, the throwout bearing, and the pressure plate and finally, the light bulb came on. Everyone here needs to have that eureka moment to understand what is going on inside there. From then on I have easily gotten 100,000 out of my Porsche clutches.
When you let out a clutch you have to determine for the condition how quickly you have to do it, and it is related to the relative speeds of the two masses--the flywheel, and the transmission gear/spline. That's the reason why when downshifting you blip the throttle a bit to bring up the engine speed in anticipation of knowing in a lower gear the transmission side of the equation will be running higher than the engine.
If you can always match the transmission speed to the engine speed you will have no clutch wear, whatsoever. Since that is nearly impossible, you attempt to bring them as close as your skills will allow.
From a dead stop, you just ease out a little throttle (gas) just enough to keep the engine from dying when suddenly the transmission is engaged. You would be amazed out slowly you need to be going in first gear before you can have the clutch pedal fully disengaged. (I have checked and for me it is routinely about 4mph).
I hope this helps. When something is so second-nature for me (and I'm sure for others) it's often difficult to explain in words. For a 911 in particular, things are a bit different because you get virtually no slippage from the tires. All that rear weight over the tires will take tire slippage out of the equation. You have to be much more gentile with a 911.
it's almost like ballet, with your feet. You give the engine just enough gas to keep it from stalling out, while simultaneously letting out the clutch. Then, with the clutch pedal out you can start to hammer it.
What will burn up a clutch is giving it a lot of gas (engine speeding up) while the transmission and the wheels are still going slow. The intersection of those two different speeds has to be sorted out by the clutch, and it will wear when you do that, by essentially slipping it.
When I was a kid, buying my first Porsche, I was going through clutches a lot--I had no idea what was going on inside there. I went to the repair shop and watched to see the interaction between the flywheel of the engine and the clutch plate, the throwout bearing, and the pressure plate and finally, the light bulb came on. Everyone here needs to have that eureka moment to understand what is going on inside there. From then on I have easily gotten 100,000 out of my Porsche clutches.
When you let out a clutch you have to determine for the condition how quickly you have to do it, and it is related to the relative speeds of the two masses--the flywheel, and the transmission gear/spline. That's the reason why when downshifting you blip the throttle a bit to bring up the engine speed in anticipation of knowing in a lower gear the transmission side of the equation will be running higher than the engine.
If you can always match the transmission speed to the engine speed you will have no clutch wear, whatsoever. Since that is nearly impossible, you attempt to bring them as close as your skills will allow.
From a dead stop, you just ease out a little throttle (gas) just enough to keep the engine from dying when suddenly the transmission is engaged. You would be amazed out slowly you need to be going in first gear before you can have the clutch pedal fully disengaged. (I have checked and for me it is routinely about 4mph).
I hope this helps. When something is so second-nature for me (and I'm sure for others) it's often difficult to explain in words. For a 911 in particular, things are a bit different because you get virtually no slippage from the tires. All that rear weight over the tires will take tire slippage out of the equation. You have to be much more gentile with a 911.
08-19-2011, 10:15 PM
#18
Racer
At a stop sign, I rev up the engine slightly and by 4 mph, have the clutch fully disengaged. THEN, and only then do I accelerate with the accelerator pedal. These people who drop the clutch are simply adding to their maintenance costs by that action.
it's almost like ballet, with your feet. You give the engine just enough gas to keep it from stalling out, while simultaneously letting out the clutch. Then, with the clutch pedal out you can start to hammer it.
What will burn up a clutch is giving it a lot of gas (engine speeding up) while the transmission and the wheels are still going slow. The intersection of those two different speeds has to be sorted out by the clutch, and it will wear when you do that, by essentially slipping it.
When I was a kid, buying my first Porsche, I was going through clutches a lot--I had no idea what was going on inside there. I went to the repair shop and watched to see the interaction between the flywheel of the engine and the clutch plate, the throwout bearing, and the pressure plate and finally, the light bulb came on. Everyone here needs to have that eureka moment to understand what is going on inside there. From then on I have easily gotten 100,000 out of my Porsche clutches.
When you let out a clutch you have to determine for the condition how quickly you have to do it, and it is related to the relative speeds of the two masses--the flywheel, and the transmission gear/spline. That's the reason why when downshifting you blip the throttle a bit to bring up the engine speed in anticipation of knowing in a lower gear the transmission side of the equation will be running higher than the engine.
If you can always match the transmission speed to the engine speed you will have no clutch wear, whatsoever. Since that is nearly impossible, you attempt to bring them as close as your skills will allow.
From a dead stop, you just ease out a little throttle (gas) just enough to keep the engine from dying when suddenly the transmission is engaged. You would be amazed out slowly you need to be going in first gear before you can have the clutch pedal fully disengaged. (I have checked and for me it is routinely about 4mph).
I hope this helps. When something is so second-nature for me (and I'm sure for others) it's often difficult to explain in words. For a 911 in particular, things are a bit different because you get virtually no slippage from the tires. All that rear weight over the tires will take tire slippage out of the equation. You have to be much more gentile with a 911.
it's almost like ballet, with your feet. You give the engine just enough gas to keep it from stalling out, while simultaneously letting out the clutch. Then, with the clutch pedal out you can start to hammer it.
What will burn up a clutch is giving it a lot of gas (engine speeding up) while the transmission and the wheels are still going slow. The intersection of those two different speeds has to be sorted out by the clutch, and it will wear when you do that, by essentially slipping it.
When I was a kid, buying my first Porsche, I was going through clutches a lot--I had no idea what was going on inside there. I went to the repair shop and watched to see the interaction between the flywheel of the engine and the clutch plate, the throwout bearing, and the pressure plate and finally, the light bulb came on. Everyone here needs to have that eureka moment to understand what is going on inside there. From then on I have easily gotten 100,000 out of my Porsche clutches.
When you let out a clutch you have to determine for the condition how quickly you have to do it, and it is related to the relative speeds of the two masses--the flywheel, and the transmission gear/spline. That's the reason why when downshifting you blip the throttle a bit to bring up the engine speed in anticipation of knowing in a lower gear the transmission side of the equation will be running higher than the engine.
If you can always match the transmission speed to the engine speed you will have no clutch wear, whatsoever. Since that is nearly impossible, you attempt to bring them as close as your skills will allow.
From a dead stop, you just ease out a little throttle (gas) just enough to keep the engine from dying when suddenly the transmission is engaged. You would be amazed out slowly you need to be going in first gear before you can have the clutch pedal fully disengaged. (I have checked and for me it is routinely about 4mph).
I hope this helps. When something is so second-nature for me (and I'm sure for others) it's often difficult to explain in words. For a 911 in particular, things are a bit different because you get virtually no slippage from the tires. All that rear weight over the tires will take tire slippage out of the equation. You have to be much more gentile with a 911.
08-21-2011, 09:59 PM
#19
Race Director
Interesting, I heard similar from my mechanic about flywheel replacement. 80% does seem high to me though.
Did he offer any insight how to avoid flywheel replacement? My indy mechanic said to not replace clutch too late or else flywheel gets damaged. All this subjective language gets be a confused. I'm going to keep my clutch until I get some signs, as others indicated my clutch might last for years to come.
Did he offer any insight how to avoid flywheel replacement? My indy mechanic said to not replace clutch too late or else flywheel gets damaged. All this subjective language gets be a confused. I'm going to keep my clutch until I get some signs, as others indicated my clutch might last for years to come.
The flywheel will 'tell' the mechanic if it needs replacing or not. Many shops, dealers service departments included, just replace the flywheel out of hand. The better ones though know how to determine the FW is ok and only replace those that need replacing.
About the only other thing you can do is avoid slipping the clutch any more than you have to to get the car moving, avoid using the clutch to slow down the car or using the clutch to hold the car on an uphill grade, shift the tranny into neutral at a stop and at the first signs of clutch slippage have the clutch replaced. A slipping clutch will overheat and possible ruin a FW.
Sincerely,
Macster.
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dgcate (07-04-2019)
08-30-2017, 11:05 AM
#20
Racer
Dan, Very Well Said - I have gotten well over 100K Miles from both my 996 OEM, as you said, I too started out @ 19 with my first Porsche 944 Turbo, I remember I only had two days prior of learning to drive 6speed, I stalled 18 times before getting home (which was only 4 miles away) I practiced over and over again until I had the feeling and understood the process. This is way before the Internet, so I went to various Librarys and Performance shops to learn.
08-30-2017, 07:04 PM
#23
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Clutch just started slipping the other day after feeling (basically) completely fine during my short ownership period. I know how to drive a manual. Pretty sure the clutch has been subjected to a few DEs and track days prior to my ownership. As much as I am not happy about a $3k+ bill (Canada ftw), I will enjoy my low mileage 911 with a brand new OEM Porsche clutch.
09-07-2017, 01:34 PM
#25
I did the clutch on mine at the same time as the IMS because it made sense to do so. The car had 50k miles on it, clutch had some wear but was still fine. I just wanted to knock it out while in there instead of having to come back in a year or whatever. Made sense to me at the time.
06-17-2019, 04:09 PM
#26
My 2007 Targa 4S has a little over 80,000 miles on it and there is no documented clutch replacement in the service history. When I bought it, the clutch felt the heaviest and trickiest to engage of all the 911's I was test driving at the time with a little bit of "chatter" when engaging but was still totally workable (when I decided to buy, there was a full PPI and I factored in the potential cost of a new clutch into my purchase decision).
Anyway, it's been 5,000 miles since purchase and the clutch is only getting harder to engage smoothly. When I took it in for 80,000 mile service the SA, without any prompting, immediately noted that based on "pedal feel" he thought it needed a new clutch ASAP.
My understanding is that on "S" models, the self-adjusting clutch can make it hard to tell if/when the clutch is starting to slip other than the pedal starting to feel heavier and the engagement a little "sharper" and higher up in the pedal (https://rennlist.com/forums/997-foru...-humbug-2.html ). My car doesn't slip when floored in 4th at 35mph.
I also want to avoid trashing the flywheel. I want to extract as much usable life out of the first clutch, but I also wouldn't mind a much easier to drive car (especially when hitting stop and go traffic). I'm sure it'll need to be done sometime soon, so wondering if there's any reason to wait, or just do it now?
Anyway, it's been 5,000 miles since purchase and the clutch is only getting harder to engage smoothly. When I took it in for 80,000 mile service the SA, without any prompting, immediately noted that based on "pedal feel" he thought it needed a new clutch ASAP.
My understanding is that on "S" models, the self-adjusting clutch can make it hard to tell if/when the clutch is starting to slip other than the pedal starting to feel heavier and the engagement a little "sharper" and higher up in the pedal (https://rennlist.com/forums/997-foru...-humbug-2.html ). My car doesn't slip when floored in 4th at 35mph.
I also want to avoid trashing the flywheel. I want to extract as much usable life out of the first clutch, but I also wouldn't mind a much easier to drive car (especially when hitting stop and go traffic). I'm sure it'll need to be done sometime soon, so wondering if there's any reason to wait, or just do it now?
06-17-2019, 07:38 PM
#27
There are many 911 drivers who, to this day, still don't know how to properly drive a manual transmission car. They wind up with premature wear of the clutch. These things should last at least 100,000 miles. If you're pressing on the 'go' pedal and the clutch pedal is not all the way released you are shortening your clutch life.
Granted, porsche does rev up more easily than BMW, and the engine is torquier. All contributes to more wear on the clutch disk, but I still think the clutch, if driven properly, should last 75K-100K miles.
06-18-2019, 02:34 AM
#28
Nordschleife Master
On my -06 C4S it just started to get really heavy. I believe it was self adjusting on the 997.1 S cars and as they wore out they required more and more pressure. Everything worked just fine. No slipping or anything else so that was the only hint it was time. Traded it for the -09 C4S in that condition and the dealer said nothing about it, nor did they back off on the trade in price agreed on over the phone so that saved me that expense. Not sure but I would expect the 997.2 to be configured the same way.
06-18-2019, 10:56 AM
#29
RL Community Team
Rennlist Member
Rennlist Member
I have some conflicting information about an S pressure plate. Read my thread on my clutch and symptoms. This guy said the self adjusting pressure plate cannot be easily reset and must be replaced anyway.
https://rennlist.com/forums/997-foru...l#post14656242
Regarding replacing a clutch "while you are in there".... not my approach (at least for something that expensive). I got 197K on one Porsche clutch and 119 on another..... how many miles a year do you drive? Your history of wearing out clutches? Money is too expensive for me to be spending like that. Further, a tech can estimate percentage of wear and then project how many miles the clutch will go. If it goes out two years.... forget it.
Peace
Bruce in Philly
https://rennlist.com/forums/997-foru...l#post14656242
Regarding replacing a clutch "while you are in there".... not my approach (at least for something that expensive). I got 197K on one Porsche clutch and 119 on another..... how many miles a year do you drive? Your history of wearing out clutches? Money is too expensive for me to be spending like that. Further, a tech can estimate percentage of wear and then project how many miles the clutch will go. If it goes out two years.... forget it.
Peace
Bruce in Philly
06-18-2019, 03:36 PM
#30
I guess my main question is: at what point should you replace the clutch on an "S" model given that it has the self-adjusting clutch system?
A) When it "feels" like it in order to avoid damage to pressure plate and/or flywheel?
- e.g. high mileage, pedal is really heavy, clutch engages high up on pedal travel, and hard to engage smoothly in 1st gear
OR
B) When it actually starts slipping (but might be too late to save the pressure plate and/or flywheel?)
Right now I'm in A. Sometimes on a shallow hill it slips a little from a start (for steep hills I use the e-brake to avoid excessive riding of the clutch)
A) When it "feels" like it in order to avoid damage to pressure plate and/or flywheel?
- e.g. high mileage, pedal is really heavy, clutch engages high up on pedal travel, and hard to engage smoothly in 1st gear
OR
B) When it actually starts slipping (but might be too late to save the pressure plate and/or flywheel?)
Right now I'm in A. Sometimes on a shallow hill it slips a little from a start (for steep hills I use the e-brake to avoid excessive riding of the clutch)