The clutch is out and the inside surfaces next to the floater are gone. There's tremendous friction material everywhere inside. Not sure just yet what that means. It's going to be a he said/she said. Anyone have experience with Mcleod clutch know how to determine what caused it? Is it the install? Is it misuse? Clutch went through the 500 mile breakin period and really was pampered (Self control is something a 40 y/o finally learns in life believe it or not :D ) I just don't want to have it rebuilt and have it happen a second time because I never learned the cause the first time around.

The next few hundred miles were all on the street and while there was some aggressive shifting, nothing really that bad. No clutch dumps or anything. The first time on the strip it died after the 6th pass. Four pass using line lock burn outs to heat the tires and the last pass the line lock burn out I'm told was with the tires (NOT SPINNING), rather the clutch smoking. I still ran hard, but it would not pull after I tried turning around at the end of the strip.

I'm looking to try and learn what happened to my clutch. Just do not want to repair/replace and do it again. Advice/thoughts appreciated.

2k1vert


[Modified by 2k1vert, 4:58 AM 5/18/2004]

 

first I would contact your vendor, then I would contact Red (I believe that is his name) @ McLeod and tell him about what happened. He will work with you and rebuild it so you wont have that problem anymore. BTW, are you aware of the ability of the clutch to slip if you dump it at too high of an RPM? Its a part of the torque management program that is in all of our cars.

VR :cheers:


[Modified by vetterdstr, 6:20 AM 5/18/2004]

 

Thanks for the advice. I contacted McLeod today and spoke with Les. He asked me a few questions:

1) Were you at the Drag Strip when it went out - Yes
2) Did you burnout or launch around 3000-3500 rpm - Yes
3) Where is your peak power randge? - 3500-4500 (based on poor memory)
4) Did your tires spin when it happened? - No, based on spectators my clutch was pouring out smoke but tires were hooked.
5) Did it happen when you were warming up the tires - Yes

I was told the problem was that I launched at too low RPM. That I should launch 1500RPM above where I make max power to ensure that the power needed to break the tires loose occurs, so he said using 4500 RPM as max power that I should be launching at 6000RPM. There is no way in heck, that I'm gonna take a stock drivetrain (shafts) and launch on hot tires at 6000rpm.

Now, I will be scared to do line lock burnouts or launch off the line for fear of having to tear everything out again. I had the mindset that the clutch would have no problem talking the power I have. Les indicated to me that launching that low and tires sticking forces something to take the punch. The clutch, rearend, shafts or torque tube. I guess it makes sense, but I still feel like I do not know how to protect myself the next time around short of just don't dump the clutch. :nopity

So Red @ McLeod can make it better than new? So it will handle much more abuse?

I've had my tuner modify my torque management settings in the PCM. As I recall to prevent it from pulling to much timing or reduce the amount of time it takes to regain timing after it happened. I can't remember what exactly right now.

Thanks for your advice VR.

Regards
2k1vert


[Modified by 2k1vert, 10:58 PM 5/18/2004]

 

Sounds to me like you may have been slipping the clutch while starting the burnout instead of popping the clutch. Any slipping will start the clutch slipping and super heat the clutch material and you will find the material tends to fall off the disk at that point. Did it once in my C4 and a McLeod clutch disk a long time ago and burnt up the clutch in just one burnout. You really have to pop that clutch when doing the burnout, whether that means revving it up to about 4K and dumping it or just dumping at 3k it should make no difference if the tires are wet. Once that clutch starts spinning and the tires are planted, then it has little choice but to burn itself up.

 

Out of everything I've heard and read, I believe you just convienced me that is exactly what I believe I did. I don't think my tires were that wet and I believe I may have let out on the clutch rather than dumping it. I've been a bit worried about snaping half or output shafts. I can not remember which is most likely to break and hence I should upgrade while I have everything pulled out. Man, I'm so glad you took the time to write this. I really appreciate everyone taking the time to comment, but this reply really seemed to hit a note with what I believe happened. Thanks dude!!!

If you can, let me know what shafts you feel should be upgraded. I don't want to give up burnouts and I'm very nervous about tearing things up. If there is 1 or more shafts that I should be concerned about, then I'd like to try and cover that before it goes back together.

Thanks again
Richard :cheers:

 

:yesnod: :mad

 

I could sell you the output shaft you need. It is the driver's side output shaft that tends to break. They are 300.00

DO you happen to have an adjustable master cylinder? How far off the floor does the clutch engage?

 

Yes, I do have an adjustable M/C which allows the clutch to engauge the first disc at roughly 3" off the floor and the second disc roughly 5" off the floor.

I may take you up on the half shaft. I want to do a little more reseach to see roughly what percent of the folks break which shafts. I believe I have read it is primarily the one you mentioned, but I would like to know how often the other breaks, how often the output shafts break etc.

Thanks :cheers:

 

*edit* Not half-shafts:) output shafts;) Normally people do not break half shafts.

There are 2 output shafts in our rear end.

A short side (not available from anyone yet) and a long side (the one that breaks 99.9% of the time)

I have not ever seen anyone break a short side output shaft, although I heard about one person doing it.

Fact is that with 600+ RWHP cars the short side is not a problem.

About your master, I was thinking it could be adjusted improperly, which would cause the problem you were having. Since you are putting a new clutch in anyways....double check to insure it is adjusted properly.


[Modified by z0sense, 11:54 PM 5/18/2004]

 

Richard, I am just beginning to mod up my Z06 and from what I have seen Joe "The One" go through at the strip over the past couple of years I am planning on upgrading the output shaft as mentioned above and I also have a DTE tranny brace that is all ready to go in as well. The second item keeps the tranny and differential from torqueing over and cracking the rear end case. Got another guy in our club that broke several rear end cases using that clutch and finally gave up on the street twin. He never tried the tranny brace though.

Interesting you are saying you can tell the one disk is being engaged at 3" and the other at 5". There really should be little indication that there are two disks in the setup. I wonder if the floater may need to be shimmed differently than how you have it. Other than the clutch having a little more pressure and more grip, it should drive exactly as a single disk would. Did you tell Red this information at McLeod? This would also explain how you were able to burn up one disk by slipping the clutch.

Chris

 

I believe you nailed it... After speaking to Red @ McLeod I'm pretty sure this is what resulted in my spun cluth... During my burnout, I believe I did not have the RPM's high enough to turn over the tires on a very hot & sticky VHT track, so the clutch just spun and super heated to over 600 degrees and caused the resin to let the yarn slide right off the plates to the bottom. Basiclly I believe it comes down to it being my first time and not knowing any better. I should be burning out in the water and not pulling out of it before starting my burnout. McLeod can rebuild it so it has better friction material using Kevlar, but that does not change the point at which the super heating will occur, so I can still have a repeat performance if I don't launch at an RPM high enough to turn the tires over. I'm thinking I will probably replace the long output shaft with a hardened one and maybe a tranny brace as well.

Thanks everyone for your comments.

2k1vert