Clutch Question - Collar length again

Mr.G

Club Member
Hi all,

Need your take after removal of my S130 gearbox at the weekend, which mates to my L28 engine with 280ZX 2+2 clutch.

Gearbox was removed in order to upgrade the clutch as it was slipping, now on removal I measured the collar out of curiosity and found it to be 30mm from the top of bearing to the top of the collar, please see attached photo.

My limited understanding is that when you are using a 280ZX box with a 280ZX 2+2 clutch, then you need the longer collar as the 280ZX pressure plate is shorter then the 240Z plate and hence you need the longer collar to make up for the length.

However if this were the case then why is mine the shorter one, and I had no issues changing gear whatsoever. Now I need to replace my thow out bearing and don't know whether I should source a 40mm collar and use that or stick with the collar I already have and just renew my bearing to that.

Also, does anyone think that my slipping clutch, when i hit 5,000rpm, can be attributed to the shorter collar being used?

Rob Gaskin wrote a very useful post on collar lengths but the attacment in his post has since expired, Rob could you shed some light here please if possible.

Thanks all.
 

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johnymd

Club Member
I'm no expert on this matter but did go though the problems of wrong length collar when I put my 280zx box in. My clutch would not engage so I neaded a longer collar in order for it to work. Even with the longer collar I still had to increase the slave cylinder pushrod length in order to get it to work properly. So, if your clutch opperated in the middle of your pedel travel before you took it apart then it will be fine if you just replace the bearing. The clutch slip when you hit near maximum engine torque probable indicates you need an uprated clutch. How much power are you trying to put through what I assume is a standard clutch? I spoke to Competition clutches yesterday and they are putting together a ceramic plate clutch for £450. I know that's not cheap but I've listened to what people have told me and I neaded to spent a bit of money if I wanted the clutch to last/survive.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
George, you are correct the 280 clutch is 'shallower' than the 240 clutch and uses the longer collar to compensate.

I would think your collar is the same as the longer one in my picture because you are already using 280 components, I'll measure it. However I do suspect there are 3 collars :-(
 

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Nigel Brook

Well-Known Forum User
Hi all,

Need your take after removal of my S130 gearbox at the weekend, which mates to my L28 engine with 280ZX 2+2 clutch.

Gearbox was removed in order to upgrade the clutch as it was slipping, now on removal I measured the collar out of curiosity and found it to be 30mm from the top of bearing to the top of the collar, please see attached photo.

My limited understanding is that when you are using a 280ZX box with a 280ZX 2+2 clutch, then you need the longer collar as the 280ZX pressure plate is shorter then the 240Z plate and hence you need the longer collar to make up for the length.

However if this were the case then why is mine the shorter one, and I had no issues changing gear whatsoever. Now I need to replace my thow out bearing and don't know whether I should source a 40mm collar and use that or stick with the collar I already have and just renew my bearing to that.

Also, does anyone think that my slipping clutch, when i hit 5,000rpm, can be attributed to the shorter collar being used?

Rob Gaskin wrote a very useful post on collar lengths but the attacment in his post has since expired, Rob could you shed some light here please if possible.

Thanks all.

The correct length for the collar using a ZX 2+2 flywheel and clutch is 35mm and the "ears" where the clutch fork sits should be 10mm from the top ( this length varies from collar to collar). You should also use the ZX clutch fork and slave cylinder. I know these dimensions are correct as I have parted out 3 manual ZXs and they were all the same.
Any mismatch of these components could indeed result in clutch slip.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
This may confuse:

The larger of the two collars in my picture (and the actual one used by John - now returned) is 40mm (10mm from ears).

George, when you get your new clutch measure it's height and compare it with the old one - if it's the same keep the collar you have.

I'm sure your clutch slip will be insufficient clamping for the power output you have.

A shorter collar will not cause clutch slip, it's the opposite way round.
 
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Mr.G

Club Member
The clutch slip when you hit near maximum engine torque probable indicates you need an uprated clutch. How much power are you trying to put through what I assume is a standard clutch? I spoke to Competition clutches yesterday and they are putting together a ceramic plate clutch for £450. I know that's not cheap but I've listened to what people have told me and I neaded to spent a bit of money if I wanted the clutch to last/survive.

John, I also suspect my clutch slipping is also due to too much power for the clutch to take, but wondered if having a different size collar then "what has previosuly been documented as the correct one to have" has been a contributing factor to the slippage. I'm now moving on to an ACT street clutch kit, should be amble for what I plan on making.

The correct length for the collar using a ZX 2+2 flywheel and clutch is 35mm and the "ears" where the clutch fork sits should be 10mm from the top ( this length varies from collar to collar). You should also use the ZX clutch fork and slave cylinder. I know these dimensions are correct as I have parted out 3 manual ZXs and they were all the same.
Any mismatch of these components could indeed result in clutch slip.

Thanks Nigel, have you taken your measurements from the same point as I have done in my photo? Rob have you done the same also? If this is the case then we have a 30mm collar (mine) , 35mm collar (one that Nigel has measured) and a 40mm collar (the tallest that Rob has seen).

Nigel, I am not sure what slave cylinder I have fitted, I might contact Mr.F to see how to identify.

Nigel and Rob, thanks for measuring.
 

Mr.G

Club Member
This now has me thinking that once I've confirmed my slave is a 280ZX unit, I should fit a 35mm collar instead of the 30mm or 40mm one.
 

Mr.F

Inactive
...and not a flame in sight for asking the same old question again...:p

Seriously though - this is a perennial problem when swapping boxes and needs to be discussed regularly!
 

Mr.G

Club Member
Mr.F has confirmed, via phone, that the slave cylinder of a 240Z and a 280ZX is the same, so no problem there.

Rob the height of the old pressure plate is the same height of my new upgraded pressure plate.

If the concensus is that a shorter collar will not cause clutch slip, as it's the opposite way round.then i will just fit the the 30mm collar and not mess around with the 35mm or 40mm.

Mike, comes up again and again, but doesnt help that i've got a 30mm collar which on the face of it works on a 280ZX box and 280ZX clutch, which is going against the general rule established here.

Cheers.
 

Mr.F

Inactive
As per our telephone discussion, you should check release arm free play before you finalise your installation...
 

Nigel Brook

Well-Known Forum User
Mr.F has confirmed, via phone, that the slave cylinder of a 240Z and a 280ZX is the same, so no problem there.

Rob the height of the old pressure plate is the same height of my new upgraded pressure plate.

If the concensus is that a shorter collar will not cause clutch slip, as it's the opposite way round.then i will just fit the the 30mm collar and not mess around with the 35mm or 40mm.

Mike, comes up again and again, but doesnt help that i've got a 30mm collar which on the face of it works on a 280ZX box and 280ZX clutch, which is going against the general rule established here.

Cheers.

Bear in mind there are two sizes for the ZX clutch, 225mm and 240mm. I take it you are using the latter. Also, whilst the slave cylinder bodies are the same the 240 can either be adjustable or non adjustable.
 

Mr.F

Inactive
Bear in mind there are two sizes for the ZX clutch, 225mm and 240mm

In other markets this is true, but in the U.K. the 280ZX only used the 240mm friction disc. There are two types of pressure plate - 9 bolt fixing and the later 6-bolt fixing. Both use the same friction disc.

whilst the slave cylinder bodies are the same the 240 can either be adjustable or non adjustable.

Only the very first 240Zs had the adjustable push rod slave cylinder (up to 06/72 for the U.K. cars). It was also 11/16" rather than the supersession part which is 3/4". You can't buy the original version any more. Virtually all 240Zs now use the non-adjustable part which is good up to the end of the 280ZX production run in '83. I know of a small handful of customers who cling to their adjustable push rod slave cylinders and, indeed, if you have the rod and the appropriate release arm, then the supersession cylinder could be converted - might overcome some of these clutch height / carrier compatibility problems...
 

Mr.G

Club Member
Rob, a big THANK YOU! Really appreciate you posting the 40mm collar so quickly, next day delivery, outstanding. :thumbs: and a big thank you also to Mr.F for his help on the phone.

I now have 3 collars to try this weekend, will be trying out the 40mm collar first and then will be doing some clutch free play checks and go from there.

I'll let you know how i get along.
 

Mr.G

Club Member
Thanks to the Zclub members for their help with this, had a productive Saturday spent under the car, with some hands on help too - you know who you are! :bow:

In the end measured my new ACT clutch and the fingers sit taller then the 280ZX turbo 2+2 job that I had fitted previously, so went for the 30mm collar, also not forgetting Nigel's advice and others on here!!

Everything is bolted up and all appears ok when depressing the clutch pedal! The proof however will be in the pudding and still have to tighten propshaft bolts and fit the exhaust on again, as well as some minor jobs, filling gearbox with oil etc...

Whilst the car was up and the gearbox was off, I took the opportunity to remove my existing oil pan which had received a fair few dents in it's previous life and fitted my Arizona Pan with baffles which helps keep the oil where you want it on heavy accelration and deceleration, lovely bit of kit, well made, helps cool the oil as well. Attached is the only photo I took of it, which is a shame as you don't get to see the baffles very well, but you get the general idea.

I've had to order some 16mm flurosilicone pipe, the one that is oil resistant for my turbo oil discharge pipes and that should arrive tomorrow so progress will continue.

Thanks all, and I'll let you know what happens.:cheers:
 

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Sylv1

Well-Known Forum User
From my experience, there are lot of collars
4tobear_specs1a.jpg



to match diversity of clutch mechanism (example below left US 240z 4s or Euro Laurel 5s, middle ZX 240mm, right Euro 260z 5s)
Vue_generale.jpg



whatever the assembly is (with stock flywheel and clutch fork), this dimension (from flywheel contact to fork pads) has to be about 91/92mm
240z_grise_origine_fonctionnel91mm.jpg
 

SKiddell

Well-Known Forum User
May I throw in that I use a Z32 collar and bearing with an S14 fork as the're much stronger:thumbs:

(That should keep people going for another 5 pages at least)
 

Mr.G

Club Member
Well folks, got the car finished up today and went for a drive. :)

Clutch felt great, my intention was to go easy on it until it broke in but after 10 miles of careful low rpm gear changing temptation got a bit too much for me.

She pulls really hard, a lot better then before, I had a massive grin on my face until she slipped again but this time a lot later then before.

My new ACT clutch kit is rated for 410ft/lb of torque, and they state that it should have 45% better clamping force then stock. Now I've not idea what power I'm developing but I'd have thought that 410ft/lb should be good enough for me.

Now, did it slip because I need to bed it in more, and for how many miles? Or should I have fitted a strongher clutch :smash:.

Sylv, great info!

Steve, interesting collar, don't know enough about it, sounds like you've been doing a lot of experimenting.
 
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