ZSpeedPerformance

iTrader: (71)

Something has to be wrong inside with the clutch, Either the disk is in backwards, Bent center hub, bound on input shaft, pressure plate is bad/bent ect. It looks to be throwing far enough to release the clutch.

Did you have any issues getting the trans installed flush with the block?

track04

iTrader: (3)

I put a scope through the fork boot and could see the fingers on the pressure plate moving.
Dont know how much they should move but i was not impressed with the amount of movement.

dropped the trans and checked everything.

Flywheel on good
Pressure plate bolts on good

I could see where i think the throw out bearing was contacting the pressure plate fingers.

Only concern is the spring on the fork, and if that was on wrong.
I still dont understand how that would change anything however.

http://www.z1motorsports.com/350_g35...oducts_id=5400

My spring was installed as it is shown in this pic
http://www.z1motorsports.com/350_g35...oducts_id=5400

track04

iTrader: (3)

Trans went in easy and flush with the block. If i had a backwards clutch disk, would the pressure plate even bolt up to the flywheel?

bmyles

Yes, you can very easily install a clutch backwards. People have done it and toasted it within 50 miles.

ZSpeedPerformance

iTrader: (71)

Bearing doesnt have much movement, Normally about .300-.400" , Clutch should easily be released by .350" movement.

Check the disk for being bent, lay it on the pressure plate and check for flatness, Also make sure it is not bowed in the middle.

Make sure the disk slides easily on the input splines.

Makes sure nothing is lodged in between the disk and flywheel causing them to lock together, Loose bolt, spring, foreign object.

Check the pilot bushing

Spring is correct in the pic, If it gets put on in the other direction it will cause the fork to push away from the slave cylinder causing release issues.

If everything checks out about all that's left is a bad pressure plate that's not lifting correctly.

track04

iTrader: (3)

first two pics show the installation of the spring on the fork.




compare the pressure plate pics above to the pic from page 1 of the diy clutch install
https://my350z.com/forum/attachments...utch003pv8.jpg

the pressure plate i have has the fingers much more flat than the pressure plate in the attached pic.


New chromolly pivot ball on top, old one on bottom (i know im missing the washer on the old one)

ZSpeedPerformance

iTrader: (71)

Your clutch disk is in backwards.

track04

iTrader: (3)

woohoo, easy fix now

Ill let everybody know what happens after i swap it around

on a side note,
People mentioned installing a disk backwards and smoking it within 50 miles. My question is how do you drive 50 miles if the clutch wont disengage at all?

ZSpeedPerformance

iTrader: (71)

Just make sure the disk isn't damaged, It can get bent from being installed backwards.

ZSpeedPerformance

iTrader: (71)

Normally they just do what yous is doing, Locks up and wont release. Can't see how it would slip like that as it is trapped into the flywheel. It can hurt the center hub of the disk though as I said above.

track04

iTrader: (3)

How do i know if the center of the hub has been hurt/compromised
Would it be cracked, bent, warped?

Also,
Without a sticker stating which side is which, how do i know orientation is correct.

ZSpeedPerformance

iTrader: (71)

Look at it and inspect it closely for any bends/cracks/warpage.

Big part of the sprung center always goes on the pressure plate side, Flat side on flywheel.

The disk will not normally fit flush to the flywheel backwards and will tend to stick up a bit.

track04

iTrader: (3)

Thanks for all the help custompartZ
Do you sell throw out bearings on their own?
I need a throw out bearing, pilot bushing, clutch alignment tool, and mt-85 redline fluid.

ZSpeedPerformance

iTrader: (71)

Yes, Plenty in stock.

track04

iTrader: (3)

pm sent

Tracktimeplz

I hope bumping this is ok, my question is directly related to this post.



Ive been dealing with all of the little fits that my car seems to pitch, whenever I drive it like its meant to be driven. The car cries uncle if I try to drop the clutch at all, the clutch would completely give up if I kicked it mid corner, while on the throttle, and it absolutely REFUSES to do "standing J-turns" or drop-clutch 180s, whatever you want to call them.

After doing some reading, I decided to bleed the clutch out, running an entire new bottle through the lines to ensure no old fluid remained. This improved the pedal feel, and engagement, but the car still refused to play ball when I kicked, or dropped the clutch, and would either cut power, or in about 1/4 times, the clutch pedal wouldnt fully return. Now, I must note that the clutch holds fine, with no slip, all the way to redline. It passes the 5th gear pull, no slips, and will even chirp the tires sometimes when I hit 3rd gear. I wouldnt think that id need a new disc or pressure plate, with it driving fine under all other conditions, but im open to suggestion.

All of this, was with VDC turned off, but recently I learned that VDC OFF doesnt actually mean that the car's systems wont try to 2nd guess my actions. Ive now unplugged the Yaw Sensor, and throttle application during hard cornering is much improved, its not cutting in at all anymore, but the clutch still gives up the second I try to pop or drop it. After doing some searching, and reading these 4 pages, im planning on replacing my MC. I also want to rip out the entire hard line, including the clutch restrictor, which may be exasperating the problem.

Question is, to CustomPartz, or anyone else who has experience, when you say "VDC compatible" does that imply that cars with VDC, may have the clutch engagement altered as part of the stability system?

Ive owned about 2 dozen sports cars, and have driven many more cars at or past their limits (and mine sometimes ) I typically avoid cars with electronic nannies, that slap your hand the moment you start to have any fun, but I love Z cars, and needed a comfortable, yet fun daily. I absolutely love this car, and the only quirks about it were small enough that I could remedy, or put up with. This is one of those things, and ill be damned if im going to give up on the Z over something that should be very easy to fix


Fyi Car is a 2005 Roadster - 49k -short ram intake

Carfax says its touring, but it doesnt have steering wheel controls for the audio, so im not sure what trim level it is. Burnt orange ventilated seats, xenons, bose, if that helps.

Thanks in advance,

Clint

ZSpeedPerformance

iTrader: (71)

Not sure what you mean by the clutch gives up? If its not slipping it should be spinning the tires. Just because it doesnt slip when your in fifth gear doesnt mean it cant slip under a high RPM clutch drop, It takes a lot more ability to hold on a high RPM clutch drop than it does in 5th gear just accelerating.

What clutch are you running?

I really doubt the hydraulics are causing your issue with the exception of the pedal not returning and that is a worn out master cylinder.

A lot of the stock clutches will give up at high RPM and the pedal will get really light if you hold the clutch down and rev the engine to high RPMS. This is a pressure plate problem and cannot be fixed without replacing the clutch assy. Centrifugal force will keep the stock pressure plate from clamping down properly at high rpm.

Tracktimeplz

Interesting, yes, the pedal fails to return, each time it slips, its any RPM that I dump/pop the clutch, even 4k. If I ease the clutch out, I can apply full power right to redline, shift and chirp, shift 7k, rinse and repeat, not problems.


Its only when coming off the clutch abruptly. Ive got a new CMC arriving today, ill replace that tomorrow and do another full clutch bleed.


I bought the car about 6 months ago, 44k on the clock. The clutch feels stock, I used to sell Nissans back in 03-05, when the Z came out. Ive driven quite a few, but it has been a while.

Ive got a local shop that will replace the clutch for only 350$ labor, cant really beat that, as I dont have a lift and it would take me 8-10 hours easy. I may just get a new clutch/flywheel in a few months, if this doesnt solve it.


Ill update tomorrow, thanks for the reply

Tracktimeplz

Late update here, got hung up on the clutch master cylinder install because the factory hardline was a ***** to thread. I decided to go ahead and rip out the entire hardline, and run a custom stainless-braided line straight from Master to Slave.

This eliminated the stupid clutch orifice, or clutch restrictor as it should be called, which could have been the cause of my problem too. Either way, my clutch works perfectly now, and I did a standing Jturn with about a 4K rpm clutch drop. Glad to have the car working on the same page finally


I will post pics and a write up in an appropriate thread


Thanks,

Clint

SharX59

iTrader: (3)

I'm having a hell of an issue! I have a 2007 350z.

I had a gtr master tech do the install of my JWT clutch/flywheel and clutch slave cylinder. After bleeding and putting everything together the pedal would only have pressure 3/4th of the way down. We re-bleed and re-bleed and found out the the nipple on the zspeed slave was defected. The nipple would allow fluid to leak out every time I depressed the clutch and air to be sucked in every time the clutch traveled up. This caused a soft pedal feel. We modified the nipple and it wasnt leaking anymore. We re-bleed it once more and the pedal felt stiff. But after a few pumps the pedal went back to the way it was. It started to feel mushy.

Now my master cylinder was fine before clutch install.

I did not adjust the pedal after I installed the new clutch.

Is there anyone that has a fix?

I have a track event in a week and with this, I won't have much time to break in the clutch.