Slipping Clutch.

[glassguy]

I just took my 71 240Z for its first test run after doing an auto to manual tranny swap. Its a 5 speed out of a 78 Z. The push rod on the slave cylinder was too long, and was keeping me from being able to mount it without engaging the fork a little, so I cut about 1/4" off the rod so I could attach it without resistance. Taking off in 1st seems fine, but then as I get into 3rd, 4th, and 5th it slips when I punch the throttle. So I chopped another 1/4" off and it's like it just keeps self adjusting and wont let the clutch fully engage. The clutch and pressure was bought from a guy some time back who said these would work fine for my  tranny setup. They were new. Could I have the wrong setup here, or is there an adjustment procedure I need to do? 

[beermanpete]

One common place to get tripped up is the throwout bearing collar. There are several different length collars and the length must match the presure plate you use. If the collar is too long it can hold the clutch in a partially released position. conversely, if hte collar is short the clutch will not fully release when you press the pedal down. to check this you must remove the engine and/or transmission.

 

When the clutch is engaged (foot off the pedal), is there a lot of force on the push rod at the slave cylinder? Can you press the slave piston back into the bore at all?

[Diseazd]

If it's a 240Z clutch, use the collar for the 240z. If it's a 280Z clutch, use the collar for that clutch. Throw out bearings are the same. If you don't match the collar to the clutch, you'll be screwing with it forever. You can choose either clutch and collar for the 5 speed but collar and clutch have to match. I always match the arm lever too......240z arm to 240Z clutch and 280Z arm to 280Z clutch.

Edited March 7, 2015 by Diseazd

[nix240z]

This post will help with the collar.

 

http://www.classiczcars.com/topic/27991-wont-go-into-gear/?p=246659

[Zed Head]

Here's another - http://www.classiczcars.com/topic/44389-l28-is-toasting-my-240z-clutch/page-2

 

92-95 mm from the fork surface of the collar to the flywheel surface is the key.  That puts the end of the fork in the right spot for the slave cylinder and its rod.

 

By the way, when Diseazd says "clutch" I think that he's talking about the whole assembly of pressure plate aka "cover" and clutch disc.  The pressure plate and its cover come in different heights, that need different throwout bearing collars.

[Diseazd]

Zed.........clutch is pressure plate with fingers........disc goes between the pressure plate and flywheel.....

Edited March 7, 2015 by Diseazd

[glassguy]

I think I have the wrong collar. I remember when I was mating the trans to the engine that no matter how hard I tried I couldn't get it to slide together the last 1/8 to 1/4 inch or so. So, I did what you should never do. I ran the bolts in and pulled it together that way. And I'll just bet that the throw out bearing is keeping just enough pressure on the clutch fingers when my foot is off the clutch, causing the slight slippage at higher rpm's. 

[Zed Head]

It's happened before.  You probably got the collar and bearing with the transmission and the pressure plate and disc separately, right?  Bummer.  Hopefully the parts didn't take too much heat.

 

Some clutch kits come with a collar included so there's no mismatch possible.  

[glassguy]

Beermanpete..... Yes, there is alot of pressure. I can't move it at all. The fork has no play at all either. I think I'll be pulling the trans tomorrow. I can assume I'll need a shorter collar, but how do I figure out which shorter one, and I already checked out my local parts suppliers, and they only offer the bearings. I guess It's another week to wait on parts.

[glassguy]

Yes ZED, it was a hodge podge of parts that I figured I'd roll the dice on. I knew something like this was bound to happen. On a positive note, the transmission shifts through all 5 gears flawlessly and reverse works!

[Zed Head]

Look through the link in Post #5.  It shows how to take a measurement that will tell you how far off your collar is.  

[glassguy]

I can get the collar from Oreilly's, but only in the complete clutch kit. It's only a hundred bucks. I just ordered it. It comes in Sunday. I will do the measurements from the link in post 5 before I reassemble it. 

 

Thanks again!