Those with adjustable clutch stops

wss4 · 12-05-2015, 08:30 PM

About 5,000 miles ago I did a major refresh on my car, including a new transmission, clutch, short shift kit, and adjustable clutch stop, among many other things. The shifting has been fairly notchy and stiff ever since, but I attributed it to the general nature of these transmissions, plus the short shifter, stiffer bushings, different fluid, etc (the following is what happens when you change too many variables at once). I got into the habit of giving a small blip on upshifts to smooth shifting out, and started giving the transmission a little more time to work.

Most recently, the shifter has been a little more difficult to get into gear on downshifts, and then while playing with different techniques I noticed that it would drop into place when I significantly over-blipped the throttle. The light bulb came on and I realized that the clutch was not completely disengaging. I was not having issues with the clutch switch, engaging reverse, or any movement of the car while in gear with the clutch in (at least at lower RPM).

I went out to screw the adjustable clutch stop all the way in, and took the car for a drive. It was a new machine - buttery smooth shifts and what felt like a lightweight flywheel while shifting. My clutch had definitely been dragging!

I don't know if this will be applicable to anyone else, but it is a quick check that could save you from burnt up synchros down the line. I know a lot of us have struggled with these transmissions, and a lot of people have aftermarket clutch stops. I feel like a bit of a fool for not realizing this earlier, and I hope I haven't done too much damage to the transmission/clutch. Amazing how something so inexpensive and seemingly benign as a clutch stop has the potential to cause so much damage!

Copied from jackstransmissions.com:

With the vehicle running, disengage the e-brake so it can roll.
Push the clutch pedal all the way to the floor and hold it there.
Turn off your launch limiter so the engine can hit the rev limiter. You MUST DO THIS!! If you do not, then there is no point in performing this test.
Shift the car into 1st gear.
Rev the engine up, while the clutch pedal is depressed all the way to the floor, until you feel the car start to move forward.

"If the vehicle moves forward below the rev limiter, your clutch is dragging. Do not drive until the problem is fixed, or your synchros will be ruined! Unit will also be hard to shift, so DON’T DRIVE OR FORCE IT INTO GEAR! If everything is correct, the vehicle will not move. If the vehicle moves forward or is hard to shift, check each of the following:"

http://www.jackstransmissions.com/pa...kills-synchros

Beedub · 12-06-2015, 05:57 AM

don't like the idea of revving the engine in neutral to the redline to check if the clutch is dragging.... surely theirs a better way than revving the shit out of the car???

inTgr8r · 12-06-2015, 07:31 AM

^ I agree.

wss4 Good info, and something to watch out for.
In addition to the clutch stop issue it could also point to potential hydraulics problems.

FWIW
A better way to check drag is to shift into 1st gear and keep clutch down, then with a slight pause in neutral, shift to reverse.
If there is drag the main shaft will still be spinning when shifting to reverse, and make it difficult to gate into gear.
If it gates into reverse cleanly, then the shaft was not spinning and thus not clutch drag.

Mirko · 12-06-2015, 08:56 AM

^^ are you moving or standing still? If still, do you have any revs while doing what you wrote? I'd be very cautious to try that with any movement so I assume you mean no movement and no revs.

wss4 · 12-06-2015, 10:27 AM

While I don't love revving the hell out of the car, I don't worry a whole lot about it if the car is thoroughly warmed up and I'm doing it rarely. What I do like about the method outlined on jackstransmissions.com is that it will definitely identify any dragging that is present. My guess is that my clutch was dragging fairly lightly, to the point that the synchros were able to compensate at lower RPM (kind of scary to think about, considering their size relative to a clutch). I did not frequently have trouble engaging reverse.

inTgr8r · 12-06-2015, 11:50 AM

Quote:

Originally Posted by Mirko

^^ are you moving or standing still? If still, do you have any revs while doing what you wrote? I'd be very cautious to try that with any movement so I assume you mean no movement and no revs.

Sorry, Done while stopped and engine at idle.

Vanne · 12-07-2015, 07:59 AM

Also... $bangs head$ make sure your clutch can go down far enough to #couff# engage the kill switch that is behind the clutch so you cant start the car in gear... bought a new ignition switch before I figured out wat was going on... koekoe..

inTgr8r · 12-07-2015, 08:56 AM

^ that's what makes the OP situation somewhat strange for our cars.
For most the switch comes into play before you get to a situation where a too high pedal stop causes drag.
It's also why I suggested checking out hydraulics and master cylinder.

Finnegan · 12-07-2015, 05:34 PM

Quote:

Originally Posted by inTgr8r

^ that's what makes the OP situation somewhat strange for our cars.
For most the switch comes into play before you get to a situation where a too high pedal stop causes drag.
It's also why I suggested checking out hydraulics and master cylinder.

Yep.

Definitely something to check and think about time to time or add on the maintenance check schedule.

The HACK · 12-07-2015, 05:58 PM

There's a simpler way to check.

Put the back end of the car up in the air with a pair of jack stands. When completely disengaged, the rear wheel should not move. If the rear wheel moves in anyway when clutch pedal is depressed, then it's dragging.

No need to try and rev the car up while clutch is depressed.

Beedub · 12-11-2015, 12:38 PM

Quote:

Originally Posted by The HACK

There's a simpler way to check.

Put the back end of the car up in the air with a pair of jack stands. When completely disengaged, the rear wheel should not move. If the rear wheel moves in anyway when clutch pedal is depressed, then it's dragging.

No need to try and rev the car up while clutch is depressed.

thats more like it.... the method suggested by OPs mechanics is a joke imo and id be very concerned about using them in the future.

12-05-2015, 08:30 PM	#1
wss4 Private First Class 35 Rep 159 Posts Drives: 2008 Z4 M Coupe Join Date: Mar 2011 Location: San Diego iTrader: (3)	Those with adjustable clutch stops - please check this! About 5,000 miles ago I did a major refresh on my car, including a new transmission, clutch, short shift kit, and adjustable clutch stop, among many other things. The shifting has been fairly notchy and stiff ever since, but I attributed it to the general nature of these transmissions, plus the short shifter, stiffer bushings, different fluid, etc (the following is what happens when you change too many variables at once). I got into the habit of giving a small blip on upshifts to smooth shifting out, and started giving the transmission a little more time to work. Most recently, the shifter has been a little more difficult to get into gear on downshifts, and then while playing with different techniques I noticed that it would drop into place when I significantly over-blipped the throttle. The light bulb came on and I realized that the clutch was not completely disengaging. I was not having issues with the clutch switch, engaging reverse, or any movement of the car while in gear with the clutch in (at least at lower RPM). I went out to screw the adjustable clutch stop all the way in, and took the car for a drive. It was a new machine - buttery smooth shifts and what felt like a lightweight flywheel while shifting. My clutch had definitely been dragging! I don't know if this will be applicable to anyone else, but it is a quick check that could save you from burnt up synchros down the line. I know a lot of us have struggled with these transmissions, and a lot of people have aftermarket clutch stops. I feel like a bit of a fool for not realizing this earlier, and I hope I haven't done too much damage to the transmission/clutch. Amazing how something so inexpensive and seemingly benign as a clutch stop has the potential to cause so much damage! Copied from jackstransmissions.com: With the vehicle running, disengage the e-brake so it can roll. Push the clutch pedal all the way to the floor and hold it there. Turn off your launch limiter so the engine can hit the rev limiter. You MUST DO THIS!! If you do not, then there is no point in performing this test. Shift the car into 1st gear. Rev the engine up, while the clutch pedal is depressed all the way to the floor, until you feel the car start to move forward. "If the vehicle moves forward below the rev limiter, your clutch is dragging. Do not drive until the problem is fixed, or your synchros will be ruined! Unit will also be hard to shift, so DON’T DRIVE OR FORCE IT INTO GEAR! If everything is correct, the vehicle will not move. If the vehicle moves forward or is hard to shift, check each of the following:" http://www.jackstransmissions.com/pa...kills-synchros
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12-06-2015, 05:57 AM	#2
Beedub Major General 423 Rep 5,328 Posts Drives: 2007 Z4 M roadster vt2-500 Join Date: Sep 2007 Location: UK iTrader: (0)	don't like the idea of revving the engine in neutral to the redline to check if the clutch is dragging.... surely theirs a better way than revving the shit out of the car??? __________________ Z4MR VT2 - Clubsport build. Multi award winning Detailing \| Wrap \| PPF specialists UK based - www.topwrapz.com
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12-06-2015, 07:31 AM	#3
inTgr8r Lieutenant General 2429 Rep 11,667 Posts Drives: M2 Comp Join Date: Mar 2006 Location: Toronto iTrader: (10)	^ I agree. wss4 Good info, and something to watch out for. In addition to the clutch stop issue it could also point to potential hydraulics problems. FWIW A better way to check drag is to shift into 1st gear and keep clutch down, then with a slight pause in neutral, shift to reverse. If there is drag the main shaft will still be spinning when shifting to reverse, and make it difficult to gate into gear. If it gates into reverse cleanly, then the shaft was not spinning and thus not clutch drag. __________________ '21 M2C Hockenheim Silver '18 718 Cayman S Lava Orange (sold) '13 E92 M3 Santorini Blue (sold) '07 Z4 M Coupe Alpine White (sold)
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12-06-2015, 08:56 AM	#4
Mirko Major 182 Rep 1,031 Posts Drives: E86 Z4M, E90 328i, E84 X1 Join Date: Apr 2011 Location: Toronto iTrader: (2)	^^ are you moving or standing still? If still, do you have any revs while doing what you wrote? I'd be very cautious to try that with any movement so I assume you mean no movement and no revs. __________________ 08 M Coupe • Ceramic Black Fabspeed Headers • MCS 1WNR • Poly FCAB • Stoptech BBK • Vibra-Tech • Epic Tune • Apex EC7 • RPI Scoop • Eventuri • Stromung • Rogue X Pipe • Varis Diffuser • CF E92 GTS Wing • CF Roof
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12-06-2015, 10:27 AM	#5
wss4 Private First Class 35 Rep 159 Posts Drives: 2008 Z4 M Coupe Join Date: Mar 2011 Location: San Diego iTrader: (3)	While I don't love revving the hell out of the car, I don't worry a whole lot about it if the car is thoroughly warmed up and I'm doing it rarely. What I do like about the method outlined on jackstransmissions.com is that it will definitely identify any dragging that is present. My guess is that my clutch was dragging fairly lightly, to the point that the synchros were able to compensate at lower RPM (kind of scary to think about, considering their size relative to a clutch). I did not frequently have trouble engaging reverse.
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12-07-2015, 07:59 AM	#7
Vanne Down Under!! 1621 Rep 4,294 Posts Drives: 2007 Z4MC Join Date: Mar 2013 Location: Dubai iTrader: (4)	Also... $bangs head$ make sure your clutch can go down far enough to #couff# engage the kill switch that is behind the clutch so you cant start the car in gear... bought a new ignition switch before I figured out wat was going on... koekoe..
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12-07-2015, 08:56 AM	#8
inTgr8r Lieutenant General 2429 Rep 11,667 Posts Drives: M2 Comp Join Date: Mar 2006 Location: Toronto iTrader: (10)	^ that's what makes the OP situation somewhat strange for our cars. For most the switch comes into play before you get to a situation where a too high pedal stop causes drag. It's also why I suggested checking out hydraulics and master cylinder. __________________ '21 M2C Hockenheim Silver '18 718 Cayman S Lava Orange (sold) '13 E92 M3 Santorini Blue (sold) '07 Z4 M Coupe Alpine White (sold)
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12-07-2015, 05:58 PM	#10
The HACK Midlife Crises Racing Silent but Deadly Class 1821 Rep 5,337 Posts Drives: 2006 MZ4C, 2021 Tesla Model 3 Join Date: Oct 2007 Location: Welcome to Jamaica have a nice day iTrader: (1)	There's a simpler way to check. Put the back end of the car up in the air with a pair of jack stands. When completely disengaged, the rear wheel should not move. If the rear wheel moves in anyway when clutch pedal is depressed, then it's dragging. No need to try and rev the car up while clutch is depressed. __________________ Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
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