Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
Clutch has a life of its own??

I have been having an issue with my clutch, perhaps you guys have some thoughts on whats going on.

As the car is cold everything works fine. it shifts smooth, and slides right into gear.

The issue is when the car gets up to operating temperatures. The clutch pedal feels the same as when the car is cold, but for some reason it is not pulling the pressure plate all the way off the clutch disk. I can feel the pressure plate-clutch disk-flywheel catching. This weekend I got stuck in traffic and the car got hotter than usual (not into the red) and I couldn't even get the car into gear. I had to roll it to a bar, and drink a few beers while she cooled down. once cold I got right back in, and everything was fine.

I have readjusted the clutch about 5 times, and it hasn't changed anything.

I thought it could be the omega spring, but wouldn't that make the pedal feel different?

Thanks for any thoughts and opinions!
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-18-2008, 10:12 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
sudo apt-get purge 930
 
equality72521's Avatar
 
Join Date: Jul 2006
Location: Brandon, FL
Posts: 4,840
Certainly sounds like thermal expansion is causing the disk to drag. Have you check the clutch arm for damage?
__________________
Mark 1979 930 Euro ***GONE AND DON'T MISS IT AT ALL***

"Worrying about depreciation on your car and keeping mileage down is like not ****ing your girlfriend so her next boyfriend finds her more appealing"
--clutch-monkey
Old 02-18-2008, 10:16 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
clutch arm is good. after the second readjustment, I took all the parts off and cleaned/inspected them.

I had used swepco on the input shaft around the throw out bearing, disk, and flywheel bearings.
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-18-2008, 10:24 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Max Sluiter
 
Flieger's Avatar
 
Join Date: Mar 2006
Location: So Cal
Posts: 19,573
Garage
maybe the clutch cable is stretching with the thermal expansion?

(I have a '71 911 with a 911 model transaxle, so I have a clutch cable. Can't remember about 915s)

just a wild guess...
__________________
911S
1971 chassis, 2.7RS spec MFI engine, suspension mods, lightened

Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance
http://www.flickr.com/photos/max_911_fahrer/
Old 02-18-2008, 10:39 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
full quack's Avatar
 
Join Date: Apr 2007
Location: Seattle-ish
Posts: 1,127
Send a message via Yahoo to full quack
Is this a new clutch assy. with new pressure plate/disc. & throw out bearing? If so, what was the running/sliding clearance between your input shaft & the throw out bearing? What material is the throw out bearing collar? Aluminum?
It is possible the clearance between the input shaft outside diameter vs. the inside diameter of the throw out bearing collar is too tight. So when the collar heats up and expands it tightens up on the shaft, thus the binding/pulling sensation you feel thru the pedal. Just a thought!
Mark
Old 02-18-2008, 11:36 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
Its a Ruf lightweight aluminum pressure plate, spring centered disk, and the extended throwout bearing (needed with the aluminum pressure plate).

The thing is, the pedal feels the same as it does when cold. I thought it was binding as well, but wouldnt I feel it catching?

I already know I am going to have to drop the engine again this week, just trying to get as many ideas of what it could be, so I will already have some thoughts before hand.

Thanks, and keep them coming!
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-18-2008, 12:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
Registered User
 
full quack's Avatar
 
Join Date: Apr 2007
Location: Seattle-ish
Posts: 1,127
Send a message via Yahoo to full quack
Hummm what a quandary....well if the pedal feels the same, it must be expansion bind. Aluminum does expand at a rate of approx. .0005 to .0007 per 10 degrees rise in temperature. But there is a limit, it doesn't expand for ever. I can not see that your running clearances on the flywheel-to-pressure plate could be so close as to cause a bind with the disc over a .010-.015 expansion of the aluminum pressure plate. Unless of course they are miss matched or miss machined.
I'm sure you will tell us all what is up after you drop the engine this weekend!
Old 02-18-2008, 06:10 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
I should have the engine dropped by tomorrow night depending on my schedule. Hopefully the issue will be obvious, and I will have her back together before going to the coast this weekend (would be 100 times better if I drove the P-car) I will be sure to keep the thread updated.
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-18-2008, 07:08 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
"I wuz the liquor..."
 
sand_man's Avatar
 
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,397
I wish I had some ideas for you, John! I hate to think of you having to drop the engine again. I'm sure by now you are a master at adjusting that clutch cable, but do you wedge a block of wood between the floor board and the back of the clutch pedal whenever you work on the cable? I have found that it helps keep the pedal in an outward position (away from the floor) whenever I loosen the cable to begin the adjustment. Just a thought. Of course I guess if it was out of adjustment, you'd have trouble shifting when it was cold too?!?!
__________________
-jeff
back in the saddle: '95 993 - just another black C2
*SOLD*: '87 930 GP White - heroin would have been a cheaper addiction...
"Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP)
Old 02-19-2008, 01:53 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
Quote:
Originally Posted by sand_man View Post
I wish I had some ideas for you, John! I hate to think of you having to drop the engine again. I'm sure by now you are a master at adjusting that clutch cable, but do you wedge a block of wood between the floor board and the back of the clutch pedal whenever you work on the cable? I have found that it helps keep the pedal in an outward position (away from the floor) whenever I loosen the cable to begin the adjustment. Just a thought. Of course I guess if it was out of adjustment, you'd have trouble shifting when it was cold too?!?!

Well the good thing about dropping the engine now is, I have done it so many time's it only takes a couple of hours (the SSI setup is well worth it). I also need to adjust the valves, fabricate piping for passenger side heat, and I have a small oil leak from the breather cover rubber hose.

How is your exhaust coming along? we will have to meet up once we both get them 100% and back on the road.
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-19-2008, 07:05 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
cycling has-been
 
bkreigsr's Avatar
 
Join Date: Sep 2004
Location: Jersey Shore
Posts: 5,183
The same thing happened to me at Watkins Glen this summer.
I'm interested to see what you find.
Bill K
__________________
73 911T MFI, 76 912E, 77 Turbo Carrera

Last edited by bkreigsr; 02-22-2008 at 09:03 AM..
Old 02-19-2008, 07:54 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
Update

Well I was finally able to find some time this morning to tear into the engine.

As I pulled off the clutch, I found that it is only engaging on the outer half of the flywheel. Any Ideas on what could be causing this? Did I torque down the clutch too much or not enough? Here is a pic. I had to turn the flash off, but you can see the outer ring




I also pulled out the pedal cluster, and it looks like it could use a rebuild.
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-22-2008, 08:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
 
cycling has-been
 
bkreigsr's Avatar
 
Join Date: Sep 2004
Location: Jersey Shore
Posts: 5,183
If it was torqued to spec, I don't see how it could be over tightened.
Maybe wrong spec?
Are the rivets in the plate still intact and at the same depth?
Bill K
__________________
73 911T MFI, 76 912E, 77 Turbo Carrera
Old 02-22-2008, 09:06 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
"I wuz the liquor..."
 
sand_man's Avatar
 
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,397
I'd like to see pictures of the clutch disk and pressure plate. Were these clutch parts new? Was the flywheel resurfaced when you had the engine out?
__________________
-jeff
back in the saddle: '95 993 - just another black C2
*SOLD*: '87 930 GP White - heroin would have been a cheaper addiction...
"Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP)
Old 02-22-2008, 09:18 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
I'll take some more pics now.

The clutch only had about 15K on it. the disc was still within spec.

I wizzered the pressure plate, but I dont think I did it deep enough. That still wouldnt cause this issue though.

What is the torque value for a 79 930?
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-22-2008, 11:07 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760




__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-22-2008, 11:27 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760




__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-22-2008, 11:29 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
full quack's Avatar
 
Join Date: Apr 2007
Location: Seattle-ish
Posts: 1,127
Send a message via Yahoo to full quack
Well I've seen worse....however looking at the 3 mating surfaces on the pressure plate, 2 look clean, the 3rd is covered with clutch dust. That 3rd surface does not appear to have been mated to the flywheel. The other 2 look as if they are slightly burnsihed from minute wiggling. Could your pressure plate be warped? Pressure plate bolts bottoming out in the holes on the flywheel just prior to clamping the pressure plate to proper torque?
Hummm...damn hard to read from just pictures...but if your pressure plate is warped that could cause disc bind, especially when hot. Also ,if you look at the release fingers on the pressure plate, the wear from the throwout bearing does not look even, but pretty minor though.
Let us know what you find out.
Mark
Old 02-22-2008, 12:57 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
Registered User
 
kellcats521's Avatar
 
Join Date: Feb 2005
Location: Atlanta Metro
Posts: 219
IMO the pilot bearing and/or trans input shaft bearing is toast. It looks like the disk is fluttering (for lack of a better word). Did you replace the pilot bearing? Did it maybe get tweaked a bit when mating the transaxle to the motor?

Good luck....
Old 02-22-2008, 01:57 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Registered User
 
Join Date: Oct 2006
Location: Raleigh, NC
Posts: 760
Will I have to replace the disc since it had 1000 miles put on with only 50% of it touching the flywheel?
__________________
John A.
1979 Porsche 930: 3.4L, SC cams, Twin plug, Leask WUR, Custom SSI turbo exhaust, Tial WG, K27HFS, and we can't forget the Zork (short lived depending on my homeowners assoc.)
05 Boxster S: For the Track.
06 Dodge Ram 2500 Power Wagon: Tow Vehicle
Old 02-22-2008, 03:00 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 02:21 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.