240z new clutch problem

[NewZed]

I meant the FS5R90A or FS5R30A versus the FS5W71B or ...C .  BW versus Nissan.  Left out the wrong letters. 

 

I thought of why the slave piston might not pop out if the short collar is used with the short pressure plate.  Maybe the back of the fork bottoms out on the edge of the hole in the case.  It would probably leave a mark.

[TrikeZ]

I meant the FS5R90A or FS5R30A versus the FS5W71B or ...C . BW versus Nissan. Left out the wrong letters.

 

I thought of why the slave piston might not pop out if the short collar is used with the short pressure plate. Maybe the back of the fork bottoms out on the edge of the hole in the case. It would probably leave a mark.

So I got the measurements for both the old and new clutches and collars.

 

I measured from outside flywheel(crank mounting surface) to outside of pressure plate fingers(TO Bearing side). Then I measured the TO bearing face to opposing collar flange.

 

On the OLD clutch and collar totaled to just over 93 mm. The NEW clutch and collar totaled to about 103.5 mm.

 

I am not sure if that is how I am supposed to measure it but those are the measurements I got.

Edited April 5, 2016 by TrikeZ

[NewZed]

Not sure what you're measuring there.  I don't see the pressure plate.

 

Here's an old picture showing the distance to measure.  Same ear you were on but measure down to the pressure plate flange.  At the flywheel surface.  The caliper isn't quite on the straight edge in the picture but it's close.  You get the idea.  Hard to hold a camera and caliper and push the button.

 

 

 

 

[TrikeZ]

Not sure what you're measuring there. I don't see the pressure plate.

 

Here's an old picture showing the distance to measure. Same ear you were on but measure down to the pressure plate flange. At the flywheel surface. The caliper isn't quite on the straight edge in the picture but it's close. You get the idea. Hard to hold a camera and caliper and push the button.

I have the pressure plate bolted to the flywheel and the assembly is up side down.

[NewZed]

Your method gives the distance from the end of the crankshaft to the top of the ears then.  Not the same as what I showed but it does imply that your old setup was shorter than what I recommended since the method measures a longer distance.  I'd just flip, stack, and measure.

 

Here's another picture for future reference.  Should have mentioned it sooner but I forgot.  It shows where the end of the clutch fork is, indirectly showing what you have inside, on a properly working clutch.  I came up with as a way to check the collar and pressure plate stack height from the outside.  It's been a while since anyone had a problem though.

[TrikeZ]

Your method gives the distance from the end of the crankshaft to the top of the ears then. Not the same as what I showed but it does imply that your old setup was shorter than what I recommended since the method measures a longer distance. I'd just flip, stack, and measure.

 

Here's another picture for future reference. Should have mentioned it sooner but I forgot. It shows where the end of the clutch fork is, indirectly showing what you have inside, on a properly working clutch. I came up with as a way to check the collar and pressure plate stack height from the outside. It's been a while since anyone had a problem though.

Old clutch does not meet your specification. While the new one does meet your specification, it did not disengage when installed.

[NewZed]

Interesting.  My thought process just opens up the spec. for that measurement down to 82 mm.  Thanks for sharing.  

 

I think that your mechanical parts are fine.  92 mm has worked for many people and it's probably no coincidence that your new pressure plate gives that number.

 

I'd go back to that 0.4 inch of travel from your hydraulics.  You can probably explore that further with the slave cylinder hanging.  You were getting less than 1/3 of the stroke you should have been getting.

[NewZed]

Just remembered something that I did on the very first clutch I ever worked on - put the disc in backwards.  It rubbed on the flywheel bolts and wouldn't disengage.

[TrikeZ]

Interesting. My thought process just opens up the spec. for that measurement down to 82 mm. Thanks for sharing.

 

I think that your mechanical parts are fine. 92 mm has worked for many people and it's probably no coincidence that your new pressure plate gives that number.

 

I'd go back to that 0.4 inch of travel from your hydraulics. You can probably explore that further with the slave cylinder hanging. You were getting less than 1/3 of the stroke you should have been getting.

Yeah, it is strange. The old system worked fine except I had a leaking master and then the old disc broke a Marcel. But other than that the slave had a homemade push rod(bolt with head ground off).

[TrikeZ]

Just remembered something that I did on the very first clutch I ever worked on - put the disc in backwards. It rubbed on the flywheel bolts and wouldn't disengage.

 

My friend told me that I might have done that but when I pulled it all back out it was in the correct way.

[NewZed]

Curious, how long is the old bolt compared to new?  You could compare while in the slave cylinder, to the new one.  I'd guess it's longer and somebody had a short collar problem.

 

I wrote a bunch about checking parts then went back and saw this - "So I just installed a new stock LuK clutch kit in my Z, new slave, master, T.O. bearing and springs, and pivot ball.".  Are you sure that pivot ball is correct?  That would cause problems if it wasn't.

 

That 0.4 inches of travel though, is still key.  If something was bottoming out mechanically, that might stop slave piston travel.  But if there's nothing stopping it you need to get it to spec.

[TrikeZ]

Curious, how long is the old bolt compared to new? You could compare while in the slave cylinder, to the new one. I'd guess it's longer and somebody had a short collar problem.

 

I wrote a bunch about checking parts then went back and saw this - "So I just installed a new stock LuK clutch kit in my Z, new slave, master, T.O. bearing and springs, and pivot ball.". Are you sure that pivot ball is correct? That would cause problems if it wasn't.

 

That 0.4 inches of travel though, is still key. If something was bottoming out mechanically, that might stop slave piston travel. But if there's nothing stopping it you need to get it to spec.

 

Yes, pivot ball was exactly the same. Old one just had some wear marks on it.

 

When the clutch was installed and in the car. I had to put in a much longer pushrod to even get the car into gear, but by doing that the TO bearing must be right up against the pressure plate and then it would get burnt out.

Edited April 6, 2016 by TrikeZ

[depair]

I'm having the same issue. I just replaced the clutch, pressure plate and TO bearing in my 71 Z. Assembled everything carefully. I also replaced the MC and Slave. Adjusted the slave to FSM spec. Bled system, adjusted the MC clevis to spec. Tested the vehicle...clutch will not fully disengage. Can't shift the transmission. The only way to get the car moving was to start it in gear....the clutch would partially disengage and allow a start, but then you can't shift when moving. Put it up on the lift and removed the rubber inspection cover on the bell housing...could see that everything looked ok and the TO bearing was engaging the pressure plate...the problem was that the clutch fork was travel limited by the bell housing opening and would not let the plate to fully disengage. The trans will have to come out...I suspect it is a problem with the replacement clutch kit. Must be a different pressure plate diaphragm spring height. Any thoughts? Were there different pressure plates used in the early cars? My production is 4/71.

[NewZed]

Sounds like you used a short TOB collar with a newer short pressure plate.  Any 225mm pressure plate from 70 - 83 will bolt on to your flywheel.  Who knows what the spring/lever height is...  Look at Post 23.  With all of the possibilities out there if you don't measure you have to get lucky.

[depair]

Yes, that is exactly what happened. The pressure plate in the new kit was, I guess, the new "short" type. I used the original TOB collar from My early 1971 car. Not realizing the pressure plate difference...because this is my first Z and every vendor lists just one type of standard clutch kit for 1970-73 cars, I put it back in the car and was only getting partial disengagement. I pulled the tranny out and measured as mentioned in this thread and it was way off. 

 

So now I'm waiting for a 280Z TOB collar to make up the difference. I also ordered another clutch kit from a different vender to see if the pressure plate is different.

 

I also have a 1973 engine/transmission that has the non adjustable clutch fork set up and the TBO collar was different from the 1971...it was about .25 inches longer...so there must have been different pressure plates used during production. None of this is ever mentioned when ordering clutch kits today!

 

I will be installing the new components this weekend and post the results.

 

Thanks for responding!

[depair]

Got the clutch kit from a different vendor. The kit is made by a different manufacturer, but it is the same pressure plate as the one I already have, i.e, short type...so I will wait for the 280Z TOB collar and post how it all goes together.

[depair]

The results are positive. the 280Z TO collar from ZCar Depot works perfectly with the newer "short type" pressure plate that is widely available these days as OEM replacements for the 240Z. I chose to use an early clutch fork with the adjustable rod and an early slave cylinder to give me the most latitude of adjustment. The combo works very well and the new clutch is functioning beautifully. Thanks to everyone who responded.