L28 is toasting my 240z clutch

[Carl Beck]

Hi Guy:

I think we have to add a disclaimer.

The 240Z clutch and pressure plate needs a 240Z collar - IF YOU ARE CERTAIN YOU ACTUALLY RECEIVED A 240Z Pressure Plate. Personally I haven't received a Pressure Plate that was exactly the same thickness as the original 240Z pressure plates - in the last 10 years.

Even if you order or specify a "240Z" pressure plate - it is very likely you will receive the newer replacement parts - which are actually 280Z pressure plates. A lot of these 240Z's have been though seveal previous owners, or to several different mechanics - so unless your the original owner you never really know for sure what you are pulling out of there.

So before you reassemble - set the old pressure plate beside the new one - on a flat surface - and measure the distance between the flat surface and the top of the pressure plate fingers. If they are exactly the same height {give or take a mm or two} then use your existing throw-out bearing collar.

If your NEW pressure plate is thinner than your old one by 3 to 6 mm - you need a longer throw-out bearing collar. In the case of a 240Z - the longer collar needed for a thinner pressure plate - will most likely be a 280Z / 280ZX throw-out bearing collar.

Measure twice - install once.

FWIW,

Carl

[Diseazd]

True Carl, but if you buy an 240Z Exedy clutch and pressure plate from MSA and use the 240Z collar, slave cylinder and arm, it'll work perfectly. I know because it's in all 5 of my Z cars....... absolutely no problems.....and will work with a highly modified L28 with no problems.

[AlexS13]

I've got an update for you guys! I recieved my centerforce stage 1 clutch last week and proceeded to remove my transmission. I was happy to see that the rear main seal was completely dry and I had no signs of oil anywhere. The flywheel had alot of heat score marks on it and was also slightly warped causing the clutch disk to not make complete contact with the flywheel. This was visible by looking at the clutch disk, there were dark patches in the friction material where it wasn't making contact. I sent out the flywheel to get machined and I just finished installing the new clutch tonight. I made my free play adjustments and took the car for a drive. Wow what a difference! The pedal feel is definitely stiffer than the stock clutch but I wouldn't consider it harsh at all. It seems to have alot more "bite" aswell while engaging. I'm making my comparision to a faulty slipping clutch so that may be part of the reason I can notice such a drastic improvement.

Overall I'am 100% satisfied with the centerforce and would recommend it to anyone who's looking for a new clutch.

[Cali71z]

Help!!! I have a 280z block and tran. After installing a new 280z clutch and pressure plate, i could shift but it's hard, i have to force it in. I bleed the master and slave cylinder and i could see the clutch folk move but still hard to shift and reverse won't even go in it just gring. when turn off engine i could shift if i move the shift around. Note: car won't shift before i change the clutch and pressure plate. Any help big thanks

[Zed Head]

Did you adjust the rod to the master cylinder to make sure that you're getting full travel? You can do it with a pair of pliers and a wrench without removing the rod if you're good at contortions. Loosen #2, and twist #4, in the diagram.

Edited November 22, 2012 by Zed Head

[Cali71z]

I give that a try! I also adjust the rod on my slave cylinder, I had adjust it forward all the way and backward all the way but still wouldn't go into gear. Ok I remember when I install my new pressure plate it's seen to be a little thinner I believe, but not that difference. So I don't know if I got the right pressure plate or I just need to bleed it more and adjust the master rod? Im about to get a 280z tran with the fork and release bearing at the junkyard and replace it to see if that works! ( I don't know if I could use a 280z slave with none adjustable rod and replace it with the adjustable rod slave)? Any help thanks!!!

[Cali71z]

Anyone knows if transmission fluid could be a issue with shifting? At the time they don't have 75-90 so I use some 80-90 none syn.?

[beermanpete]

It sounds like you might have a mismatch between the pressure plate and throw-out bearing collar. The earlier cars have tall pressure plate and a short collar. The later cars have a short pressure plate and a long collar. If you have an late (short) pressure plate and an early (short) collar the clutch won't fully release. Have an assistant press the clutch pedal down while you look at the position of the slave cylinder piston (lift the dust boot and look in the cylinder bore). If the piston is out past the end of the cylinder you have both short parts.

[Cali71z]

That's what I though to, but I press the clutch pedal down and throw in first gear start the car and gas it, the car didn't go so I dont think the clutch is stuck engage.

[zKars]

Someday we'll take all the mystery out of this never ending topic of "which collar to use with my clutch".

The way to tell what collar to use with any clutch would be really very simple, IF one knew the expected total height of the clutch + collar, which is NEVER mentioned in any thread. It is a constant for any tranny that bolts on to an L24/6/8 I'de believe.

As long as your flywheel is the "Standard" thickness then you measure your installed height from flywheel face to the clutch fingers where the throwout bearing touches them, subtract that from the "total required height" (the big mystery) and get the exact length of collar you need to have (+/- a little bit).

We need someone, anyone, everyone, who is at the point of assembling the clutch and trans, and is totally confident that he has a matched set of collar/clutch, to measure both for us and report the total.

For the collar, measure from the front face of the throwout bearing to the back of the two tabs the fork touches. Like in this picture, ie the shorter measurement.

Or put your clutch cover on the floor and put the collar w/throwout mounted on the fingers and measure it from the floor to the top of the fork pads on the collar.

Someone did it here, and reported 91 or 92 mm total height. ~3.60 inches. No clue if this is right or not.

http://zclub.net/forum/s30-240z-260z-280z-drivetrain/19228-clutch-question-collar-length-again-2.html

Lets all do it and report your measurements. We'll take the average and call it the "L_Total_Clutch_Height" universal constant and we can relax about this finally!!

I'm taking pictures of what I mean tonight with some clutch parts I have laying around that I know work to get this started.

[Zed Head]

Actually I mentioned it in a previous thread and actually gave a height. Tried to find it but the Search function of the site seems to be one of those fuzzy ones that doesn't allow an exact search. The more search words you put in the more results you get instead of the opposite.

I'll keep looking.

Found them. I took them but never posted. Ignore my previous postings, since deleted. Pictures attached. 91.36 mm, 3.6", 3 19/32" from base of pressure plate to wear the clutch fork rides on the collar. Note that when the disc is inserted the measurement will get a little smaller as the pressure plate fingers move down. Probably not a big deal. Also note that the picture and the eyeball of the caliper were done separately. The picture of the caliper beside the stack is for demonstration.

Edited November 23, 2012 by Zed Head

[zKars]

Zed head, thanks a bunch. Okay, "rarely" have I seen that measurement.

I have since tested two clutch sets. One my just replaced 240mm setup with a performance aftermarket clutch that used a tall collar, and a series 1 "A" trans with a nice tall clutch plate that had a short collar.

The short and sweet is that both added up to 91-92 mm total height as you measured it, with release bearing on the collar.

Btw the release bearing added about 3mm to the collar height.

Notice I didn't mention the collar length in both cases. No more spreading that stuff. From now on the manta is "Total is 92 mm. Measure your clutch and then pick the collar you need to get to 92mm."