Clutch adjustment on 2 plate'ers
09-09-2008, 04:07 PM
#46
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HMMM, trust Devek and not the shop manual? I loved those guys, but we all have made mistakes. This, in my mind, is clearly one of them.
this method will at best, work. at worst, as you have and i would suspect many others, would see clutch drag, especially if you have the higher pressure plate system. the equal distance makes little sense, as the rearward distance of the pressure plate and disc on the int. plate could vary. right? So, this means the adjusters could be forced to be place only a mm too far rearward causing the problem.
So, if you are saying you adjusted it the way Devek had written, then i see why you had issues. also, why did you think it changed while driving it? there is a good answer for that as well by using that technique. (it has nothing to do with the pressure of the pressure plate)
Mk
this method will at best, work. at worst, as you have and i would suspect many others, would see clutch drag, especially if you have the higher pressure plate system. the equal distance makes little sense, as the rearward distance of the pressure plate and disc on the int. plate could vary. right? So, this means the adjusters could be forced to be place only a mm too far rearward causing the problem.
So, if you are saying you adjusted it the way Devek had written, then i see why you had issues. also, why did you think it changed while driving it? there is a good answer for that as well by using that technique. (it has nothing to do with the pressure of the pressure plate)
Mk
Devek method from years ago:
Adjusting the 928 double disc clutch center ring.
The 928 double disc clutch is superior to any other production car clutch assembly. It is small in diameter, has a large surface area, low angular momentum and is easy to modulate. However, it does have one fault. Porsche discontinued the clutch at the end of 1986 because of continuing problems with having the clutch properly serviced in the field. If the center ring is out of position, the clutch, even in the fully disengaged position, will experience "drag". This drag will cause a creep when the car is standing still, in gear and idling. The clutch drag will also cause difficult shifting and grinding in reverse gear. The other aspect of the service problem is that improper lubrication of the clutch assembly and central shaft causes poor quality engagement and early failure of parts. The Fix: To properly adjust the center ring, remove the clutch cover and disengage the clutch by using a bar against the release bearing arm. In the disengaged position, the center ring should be equal distant from the flywheel and the pressure plate. If the center ring is out of position, reposition it by moving the adjusting forks of the center ring with a screwdriver. Rotate the engine by hand to gain access to each of the three adjusting forks. Disregard the dimensions given in the 928 factory repair manual! Lubricate all of the pivot points of the pressure plate diaphragm spring with dry molybdenum disulfide spray (such as Zep product #0073). Lubricate the central shaft and release bearing guide sleeve with moly paste. This procedure will assure easy modulation of, and long service life for, the double disc clutch assembly.
Adjusting the 928 double disc clutch center ring.
The 928 double disc clutch is superior to any other production car clutch assembly. It is small in diameter, has a large surface area, low angular momentum and is easy to modulate. However, it does have one fault. Porsche discontinued the clutch at the end of 1986 because of continuing problems with having the clutch properly serviced in the field. If the center ring is out of position, the clutch, even in the fully disengaged position, will experience "drag". This drag will cause a creep when the car is standing still, in gear and idling. The clutch drag will also cause difficult shifting and grinding in reverse gear. The other aspect of the service problem is that improper lubrication of the clutch assembly and central shaft causes poor quality engagement and early failure of parts. The Fix: To properly adjust the center ring, remove the clutch cover and disengage the clutch by using a bar against the release bearing arm. In the disengaged position, the center ring should be equal distant from the flywheel and the pressure plate. If the center ring is out of position, reposition it by moving the adjusting forks of the center ring with a screwdriver. Rotate the engine by hand to gain access to each of the three adjusting forks. Disregard the dimensions given in the 928 factory repair manual! Lubricate all of the pivot points of the pressure plate diaphragm spring with dry molybdenum disulfide spray (such as Zep product #0073). Lubricate the central shaft and release bearing guide sleeve with moly paste. This procedure will assure easy modulation of, and long service life for, the double disc clutch assembly.
09-09-2008, 04:14 PM
#47
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Well Mark. Seems like your now the expert on DD clutch adjustment.
Did you not read that I had no issues with the clutch for many years? Did you read Greg B. Experience here?
I would adjust, pry back the clutch lever and reach in and spin the TT by hand to make sure it was moving free. Would drive the car for a bit with no issue (this would mean it is adjusted right), then it would go out.
Did you not read that I had no issues with the clutch for many years? Did you read Greg B. Experience here?
I would adjust, pry back the clutch lever and reach in and spin the TT by hand to make sure it was moving free. Would drive the car for a bit with no issue (this would mean it is adjusted right), then it would go out.
09-09-2008, 04:15 PM
#48
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HMMM, trust Devek and not the shop manual? I loved those guys, but we all have made mistakes. This, in my mind, is clearly one of them.
this method will at best, work. at worst, as you have and i would suspect many others, would see clutch drag, especially if you have the higher pressure plate system. the equal distance makes little sense, as the rearward distance of the pressure plate and disc on the int. plate could vary. right? So, this means the adjusters could be forced to be place only a mm too far rearward causing the problem.
So, if you are saying you adjusted it the way Devek had written, then i see why you had issues. also, why did you think it changed while driving it? there is a good answer for that as well by using that technique. (it has nothing to do with the pressure of the pressure plate)
this method will at best, work. at worst, as you have and i would suspect many others, would see clutch drag, especially if you have the higher pressure plate system. the equal distance makes little sense, as the rearward distance of the pressure plate and disc on the int. plate could vary. right? So, this means the adjusters could be forced to be place only a mm too far rearward causing the problem.
So, if you are saying you adjusted it the way Devek had written, then i see why you had issues. also, why did you think it changed while driving it? there is a good answer for that as well by using that technique. (it has nothing to do with the pressure of the pressure plate)
The WSM is full of errors. I'm not saying this is one of them but there is obviously more then one way to skin this cat.
Jesus Christ Mark, why do you have to fight with everyone on everything around here?
09-09-2008, 05:48 PM
#49
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Hey, dont hate me because i spent the time to figure this one out.
Yes, i read EVERYTHING that Greg wrote and he said to push the adjusters all the way back. so did a lot of folks. Heck, I just did it blindly. in most cases, i bet it works. In fact, no adjustment has "worked" for over 20 years of owing 928s with the DDs. Greg is the Master, thats why I listened, but Im sure after reading this he probably knows even more about the DD than he did before.
To your last point, since you cant grasp the fact that there COULD be an issue with the Devek technique, yes, that could be a major problem, because, pulling the lever bar back could never simulate what the slave will do. ITS ONLY CHECKING ONE WAY RELEASE! (meaning the intermediate plate is moving back and not contacting the flyweel and disc) Everyone told me the same thing. its dragging on the flywheel, move it further back, "pry it all the way back", etc.
So, how do you know your Int. plate is not going to drag on the pressure plate? You dont because you are levering back an unknown distance, proabaly further than the slave actuation. By using the WSM, you can see that when the clutch is engaged, the int. plate only goes back far enough to rest on the "H" adjuster pads. if that adjuster is too far back, it WILL drag on the pressure plate.
When i started to really understand the mechanism, it dawned on me that the other direction could be the problem! Sure, with this honored technique, the flywheel wouldnt be dragging, BUT, the pressure plate could also. It might be close, as mine was when i changed the pressure plate to the stronger one, but the car after 2 races showed that it wasnt good. it was marginal, and went to bad. What you saw showed that the int. plate was certainly releasing from the flywheel, but after a few clutch movements over a session, the pressure plate could have been close enough to drag on the disc and intermediate plate. As i said, we are talking about 1mm of difference between good and OK and possibly BAD.
Since you didnt use the shop method, you will never know. Sure, the manual has all sorts of errors and confustion, but when PORSCHE GUARANTEES something will work, i tend to listen. I did and it works perfectly, with little chance of changing. Wanna bet i dont have a problem in the future?
mk
Yes, i read EVERYTHING that Greg wrote and he said to push the adjusters all the way back. so did a lot of folks. Heck, I just did it blindly. in most cases, i bet it works. In fact, no adjustment has "worked" for over 20 years of owing 928s with the DDs. Greg is the Master, thats why I listened, but Im sure after reading this he probably knows even more about the DD than he did before.
To your last point, since you cant grasp the fact that there COULD be an issue with the Devek technique, yes, that could be a major problem, because, pulling the lever bar back could never simulate what the slave will do. ITS ONLY CHECKING ONE WAY RELEASE! (meaning the intermediate plate is moving back and not contacting the flyweel and disc) Everyone told me the same thing. its dragging on the flywheel, move it further back, "pry it all the way back", etc.
So, how do you know your Int. plate is not going to drag on the pressure plate? You dont because you are levering back an unknown distance, proabaly further than the slave actuation. By using the WSM, you can see that when the clutch is engaged, the int. plate only goes back far enough to rest on the "H" adjuster pads. if that adjuster is too far back, it WILL drag on the pressure plate.
When i started to really understand the mechanism, it dawned on me that the other direction could be the problem! Sure, with this honored technique, the flywheel wouldnt be dragging, BUT, the pressure plate could also. It might be close, as mine was when i changed the pressure plate to the stronger one, but the car after 2 races showed that it wasnt good. it was marginal, and went to bad. What you saw showed that the int. plate was certainly releasing from the flywheel, but after a few clutch movements over a session, the pressure plate could have been close enough to drag on the disc and intermediate plate. As i said, we are talking about 1mm of difference between good and OK and possibly BAD.
Since you didnt use the shop method, you will never know. Sure, the manual has all sorts of errors and confustion, but when PORSCHE GUARANTEES something will work, i tend to listen. I did and it works perfectly, with little chance of changing. Wanna bet i dont have a problem in the future?
mk
Well Mark. Seems like your now the expert on DD clutch adjustment.
Did you not read that I had no issues with the clutch for many years? Did you read Greg B. Experience here?
I would adjust, pry back the clutch lever and reach in and spin the TT by hand to make sure it was moving free. Would drive the car for a bit with no issue (this would mean it is adjusted right), then it would go out.
Did you not read that I had no issues with the clutch for many years? Did you read Greg B. Experience here?
I would adjust, pry back the clutch lever and reach in and spin the TT by hand to make sure it was moving free. Would drive the car for a bit with no issue (this would mean it is adjusted right), then it would go out.
Last edited by mark kibort; 09-09-2008 at 06:16 PM.
09-09-2008, 06:05 PM
#50
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Thread Starter
Devek was packed full of knowledge, no question. There were some things that I did a little different that seemed to work for me.
on this topic, i just never spent the time, as i thought it was a fine tuning deal and had never had an issue before. I didnt realize that a very very slight issue could cause a little issue with the car going into 1st and reverse and a larger issue would cause it not to be able to be put in gear at all!
I probably spent more time than all of the shops studying and testing what this darn thing was all about.
Now, when someone says, "just push the adjsuter all the way to the rear" i know this is a MAJOR issue, as it can force contact when the clutch is depressed on the pressure plate, not the flywheel. I also know it can keep the intermediate plate from making good contact with the flywheel.
I bet you can get 10 cars and jsut stick a Int plate in there and have it work. I also bet if you get lucky, you can do the devek method and have it work fine. However, the reason it doesnt work, is that all you need is 1mm gap on the adjusters so that the intermediate plate can release, as Greg Brown assured. This is the truth, any more gap , shifts the intermediate plate too far to the rear where it can drag on the pressure plate surface and disc.
Im fighting because i have a passion for sharing what works. guys on this list are all over the map on everything from tunning, engine building , set up, etc etc. I like to find those things that work, and do those things. This is one of those things that was not clearly understood by many. Now, i would hope that a full disection of the system and a fix that worked instantly on two cars (and has not and will not change) would be of interest of the list.
I lean toward understanding why the WSM has shown to do things certain ways. if there is a value that "Guarantees" proper adjustement by Porsche, i certainly would want to hear of why this "new" way works vs the WSM way.
The WSM way works for the reasons i have explained. why doesnt someone explain why the other ways would work better. They might work by chance, but mechanically, they dont make any sense as it solves one percieved problem, in exchange for another. the WSM has no trade offs.
Bottomline. I did adjust the Int plate by pushing the adjusters to the rear. it grabbed the pressure plate on 2 cars and prevented the car to be put into gear.
In my book, thats wrong advice knowing what I know now. The devek way also has flaws based on how far you lever back the clutch arm. it skew's the "middle" zone and could force the adjuster to be too far to the rear. A simple test is to see where your adjusters are with your hatch. if there is a 1-1.5mm gap or less, its adjusted correctly, even if you did it the long way!
What counts is where that int. plate ends up when you push the clutch pedal. It only can go as far as the spring and adjusters let it! Where and how far it goes can ruin your day
mk
on this topic, i just never spent the time, as i thought it was a fine tuning deal and had never had an issue before. I didnt realize that a very very slight issue could cause a little issue with the car going into 1st and reverse and a larger issue would cause it not to be able to be put in gear at all!
I probably spent more time than all of the shops studying and testing what this darn thing was all about.
Now, when someone says, "just push the adjsuter all the way to the rear" i know this is a MAJOR issue, as it can force contact when the clutch is depressed on the pressure plate, not the flywheel. I also know it can keep the intermediate plate from making good contact with the flywheel.
I bet you can get 10 cars and jsut stick a Int plate in there and have it work. I also bet if you get lucky, you can do the devek method and have it work fine. However, the reason it doesnt work, is that all you need is 1mm gap on the adjusters so that the intermediate plate can release, as Greg Brown assured. This is the truth, any more gap , shifts the intermediate plate too far to the rear where it can drag on the pressure plate surface and disc.
Im fighting because i have a passion for sharing what works. guys on this list are all over the map on everything from tunning, engine building , set up, etc etc. I like to find those things that work, and do those things. This is one of those things that was not clearly understood by many. Now, i would hope that a full disection of the system and a fix that worked instantly on two cars (and has not and will not change) would be of interest of the list.
I lean toward understanding why the WSM has shown to do things certain ways. if there is a value that "Guarantees" proper adjustement by Porsche, i certainly would want to hear of why this "new" way works vs the WSM way.
The WSM way works for the reasons i have explained. why doesnt someone explain why the other ways would work better. They might work by chance, but mechanically, they dont make any sense as it solves one percieved problem, in exchange for another. the WSM has no trade offs.
Bottomline. I did adjust the Int plate by pushing the adjusters to the rear. it grabbed the pressure plate on 2 cars and prevented the car to be put into gear.
In my book, thats wrong advice knowing what I know now. The devek way also has flaws based on how far you lever back the clutch arm. it skew's the "middle" zone and could force the adjuster to be too far to the rear. A simple test is to see where your adjusters are with your hatch. if there is a 1-1.5mm gap or less, its adjusted correctly, even if you did it the long way!
What counts is where that int. plate ends up when you push the clutch pedal. It only can go as far as the spring and adjusters let it! Where and how far it goes can ruin your day
mk
Say what you want but you just started learning how to adjust these (after racing them for how long?) and the DEVEK method has worked for multiple cars I've adjusted and many others my local 928 guru has worked on. Including his track car with a higher force pressure plate.
The WSM is full of errors. I'm not saying this is one of them but there is obviously more then one way to skin this cat.
Jesus Christ Mark, why do you have to fight with everyone on everything around here?
The WSM is full of errors. I'm not saying this is one of them but there is obviously more then one way to skin this cat.
Jesus Christ Mark, why do you have to fight with everyone on everything around here?
09-09-2008, 06:28 PM
#52
Rennlist Member
Mark,
Could you do a concise write up of how you did this with pics. I know it is in your posts but I would like to have a step by step with pics and explanations. I think you may be on to something this time. I am not having any difficulty at all with my clutch and haven't done anything to it since Hacker fixed it for me at RA. I would like to have this on the shelf for a future reference.
Could you do a concise write up of how you did this with pics. I know it is in your posts but I would like to have a step by step with pics and explanations. I think you may be on to something this time. I am not having any difficulty at all with my clutch and haven't done anything to it since Hacker fixed it for me at RA. I would like to have this on the shelf for a future reference.
09-09-2008, 06:30 PM
#53
Rennlist Member
Thread Starter
Scared you might learn something by someone elses hard work. Man, I didnt know you were so closed mined.
I asked you a simple question, and you gave me the answer. you adjusted it your way and it didnt work. you blame the pressure plate, I blame the way you adjusted it. as you say, YOU CANT BE WRONG ON THIS ONE. So, I guess as they say, ingorance is bliss. It doest matter to you as you dont have a clutch like this any more, but do you know how HAPPY Scot is that this issue is fixed. ITS ruined his day and his ability to race for 2 full race weekends!! Now its fixed and he is a happy camper. I would Love to hear that this finding helps someone based on what i have found by digging a little deeper into this issue.
Here is another approach. Ive found the reason for the problem. why dont you try and find one way, one reason why the WSM will not work and try to explain it to me and the list. Sure, as Hacker says, "there is more than one way to ...") But, there is a difference between something working and something working by chance.
People always hate to argue when they are wrong or have a strong belief in something. Thats great, honor the devek way of doing this. Im hear to tell you its not the right way to do it and trust me, I bet even Greg Brown will think twice about this before he pushes those adjusters all the way rear-ward.
The great thing about this list is that i have learned more from you guys(this list), than I could ever think of contributing. If I can give back on occasion, I feel a passion to do so, even if it helps a smart *** like you!
mk
I asked you a simple question, and you gave me the answer. you adjusted it your way and it didnt work. you blame the pressure plate, I blame the way you adjusted it. as you say, YOU CANT BE WRONG ON THIS ONE. So, I guess as they say, ingorance is bliss. It doest matter to you as you dont have a clutch like this any more, but do you know how HAPPY Scot is that this issue is fixed. ITS ruined his day and his ability to race for 2 full race weekends!! Now its fixed and he is a happy camper. I would Love to hear that this finding helps someone based on what i have found by digging a little deeper into this issue.
Here is another approach. Ive found the reason for the problem. why dont you try and find one way, one reason why the WSM will not work and try to explain it to me and the list. Sure, as Hacker says, "there is more than one way to ...") But, there is a difference between something working and something working by chance.
People always hate to argue when they are wrong or have a strong belief in something. Thats great, honor the devek way of doing this. Im hear to tell you its not the right way to do it and trust me, I bet even Greg Brown will think twice about this before he pushes those adjusters all the way rear-ward.
The great thing about this list is that i have learned more from you guys(this list), than I could ever think of contributing. If I can give back on occasion, I feel a passion to do so, even if it helps a smart *** like you!
mk
09-09-2008, 06:39 PM
#54
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God bless him, when Mark thinks he has it figured out, there is just no moving him. He's extremely quick and decisive. It's a great strength and it can be a weakness at the same time. I don't know enough about the dual clutch to argue here, but I'm pretty confident there will be more to the story later.
09-09-2008, 07:26 PM
#55
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Thanks Bill, you know me well enough to know how I think. I would love to hear an arguement that doest reference other techniques that have been proven not to work. No one ever said they used the WSM technique and it didnt work or it changed after a few race sessions. What they do is quote a shop blurb from a advice section in their catalogue, and a few instances where that techique changed after a few sessions on the track. I just looked at the problem a little longer than most, (my obsessive compusive side) and gave reasons why there could be problems.
Do you think I will be recanting my claims after the next race sessions? Do you think Scot will? There is no logical reason why the setting I've used will move. If there is, I would love to hear it!. Push the clutch in too fast, the Int. plate moves rearward with the force of its own springs. let the clutch out real fast, the Int. plate pushes down via the pressure plate force toward the flywheel. If the flywheel disc is worn badly, there is a chance that the Int plate can move the stops (if they are weak) toward the front, BUT, it wouldnt matter, because naturally, there is a 2-3mm space in the "H" adjuster so, the int plate would always be able to move back. If it is adjusted correctly from the start, it should never move unless those adjusters are really loose.
The reason for the adjustement, is that you would need to colapse the "H" adjusters to the flywheel if the discs were worn badly, as the gap would grow out of spec. until it hit the bottom of the adjuster and then would not be able to apply pressure on the flywheel.
what i can do today, is explain the trade offs, charateristics of the intermediate plate adjustement. If JV was around today with his stronger DD clutch set up, I am certain that this would be a fix for him as it has been for scot and me.
mk
Do you think I will be recanting my claims after the next race sessions? Do you think Scot will? There is no logical reason why the setting I've used will move. If there is, I would love to hear it!. Push the clutch in too fast, the Int. plate moves rearward with the force of its own springs. let the clutch out real fast, the Int. plate pushes down via the pressure plate force toward the flywheel. If the flywheel disc is worn badly, there is a chance that the Int plate can move the stops (if they are weak) toward the front, BUT, it wouldnt matter, because naturally, there is a 2-3mm space in the "H" adjuster so, the int plate would always be able to move back. If it is adjusted correctly from the start, it should never move unless those adjusters are really loose.
The reason for the adjustement, is that you would need to colapse the "H" adjusters to the flywheel if the discs were worn badly, as the gap would grow out of spec. until it hit the bottom of the adjuster and then would not be able to apply pressure on the flywheel.
what i can do today, is explain the trade offs, charateristics of the intermediate plate adjustement. If JV was around today with his stronger DD clutch set up, I am certain that this would be a fix for him as it has been for scot and me.
mk
God bless him, when Mark thinks he has it figured out, there is just no moving him. He's extremely quick and decisive. It's a great strength and it can be a weakness at the same time. I don't know enough about the dual clutch to argue here, but I'm pretty confident there will be more to the story later.
09-09-2008, 07:31 PM
#56
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Thread Starter
Thanks!
Should i make a second post, or just do it at the end of this discussion?
These types of write ups have been extremely helpful to me. That Pirtle cam timing write up was printed immediately and I must have read it cover to cover a 100 times! The interesting thing about them is that with the pictures and the explanations, it removes all the confusino that the WSM creates and gave great explantions /reasons for why you were doing the things described to do.
mk
Should i make a second post, or just do it at the end of this discussion?
These types of write ups have been extremely helpful to me. That Pirtle cam timing write up was printed immediately and I must have read it cover to cover a 100 times! The interesting thing about them is that with the pictures and the explanations, it removes all the confusino that the WSM creates and gave great explantions /reasons for why you were doing the things described to do.
mk
Mark,
Could you do a concise write up of how you did this with pics. I know it is in your posts but I would like to have a step by step with pics and explanations. I think you may be on to something this time. I am not having any difficulty at all with my clutch and haven't done anything to it since Hacker fixed it for me at RA. I would like to have this on the shelf for a future reference.
Could you do a concise write up of how you did this with pics. I know it is in your posts but I would like to have a step by step with pics and explanations. I think you may be on to something this time. I am not having any difficulty at all with my clutch and haven't done anything to it since Hacker fixed it for me at RA. I would like to have this on the shelf for a future reference.
09-09-2008, 07:55 PM
#57
Rennlist Member
Thanks!
Should i make a second post, or just do it at the end of this discussion?
These types of write ups have been extremely helpful to me. That Pirtle cam timing write up was printed immediately and I must have read it cover to cover a 100 times! The interesting thing about them is that with the pictures and the explanations, it removes all the confusino that the WSM creates and gave great explantions /reasons for why you were doing the things described to do.
mk
Should i make a second post, or just do it at the end of this discussion?
These types of write ups have been extremely helpful to me. That Pirtle cam timing write up was printed immediately and I must have read it cover to cover a 100 times! The interesting thing about them is that with the pictures and the explanations, it removes all the confusino that the WSM creates and gave great explantions /reasons for why you were doing the things described to do.
mk
09-10-2008, 01:57 AM
#58
Rennlist Member
Thanks Mark. I have adjusted and re-adjusted my DD clutch on the euro and bled and re-bled the system. The problem hasn't been annoying enough to prompt me to pull the bell housing but there is nearly always a tiny creep if i start the engine while in gear and I may or may not be able to shift into 1st or reverse if I start in nuetral. I think there is light at the end of the tunnel now.
09-10-2008, 02:07 AM
#59
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Mark, like the cam experience, we have two entrenched camps. I'm in no position to write off the other techniques. I think there is an alternative explanation we haven't discovered yet. It will take some time to find it. In the meantime, be happy.
09-10-2008, 02:31 AM
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