Silvia Club of NSW

For years i had a heavy duty full face organic clutch, but it simply wore out recently (it started spinning and got worse) so i replaced it with a heavy duty ceramic/organic clutch. I was in a rush so i just chucked it in (the flywheel was still smooth so i didn't machine it), and took it to a track day. It was okish but sometimes slipped a bit in 3rd gear. So i thought instead of wreaking and thinking that the clutch just wasn't up to the power (190rwkw/255rwhp so not stacks but an ok ammount) it i'd just take it out and put in a 5 puck ceramic clutch instead.

And having a bit more time i got the flywheel machined, did 400km of normal driving to bed the clutch and then tried it out. Result is the same, the clutch spins into second gear if i just do a full power straight line run and is generally very similar to the previous HD organic/ceramic clutch.

Apart from that i've checked the slave cylinder to make sure it's not pushing on the clutch a bit and reducing the clamping pressure (I can push it in by hand and the pin that actuates the clutch fork is a touch loose when it's just sitting still). The clutch works smoothly and takes up just fine.

Normal driving is no problem, and spinning the wheels in 1st or sliding around a corner in 2nd is not a problem. Dumping it into 2nd when there is grip spins the clutch and i suspect 3rd gear clutch kicks will too. I can move the fork further out (so the throwout bearing comes off the face of the pressure plate fingers) by hand so it's not that hitting anything either it seems. Also the pedal feels very light.

Any other suggestions? I'm starting to think it just doesn't have the clamping force it should have at all!

The current clutch is a 5 puck valeo, the previous clutch was a ceramic/organic valeo (both from the same supplier).

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1996 180sx
1990 Silvia

check your pedal adjustment and for leaks at the master first,and then bleed the system if all is fine there.


Justin...

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STI - Made in Texas,not Japan.

Both are done, the clutch return itself is fine so it should be clamping at full load. It should be the opposite problem if the thing wasn't bled properly and there is no load on the pin that actuates the clutch fork when the clutch is full out so it's not that.

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1996 180sx
1990 Silvia

you did say that the pedal was quite light. is there any freeplay before it 'takes up'? a light pedal that takes up on the floor and has a spongy feel suggests a worn or leaking master cylinder. that's why I suggested to check that and the adjustment of the pushrod first.


Justin...

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STI - Made in Texas,not Japan.

are u running a heavier pressure plate?

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formerly 3AM

It's the one that came with the new clutch. It's allegedly 20% heavier than stock. Seems very light. I can remove it and the shop that sold it to me will check the clamping pressure for me.

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1996 180sx
1990 Silvia

20% heavier than stock isnt much. is it a reputable brand?

my 5 puk was running a 1400kg pressure plate. and it was pretty damn awesome.

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formerly 3AM

I just asked what the exact clamping pressure is supposed to be on that clutch, he said it's supposed to be 850kg. I have no idea weather that is alot or not haha.

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1996 180sx
1990 Silvia

You can certainly get away with alot less clamping pressure on a button clutch than you can on the equivalent full-face clutch.

I would be surprised if the rated clamping pressure is actually the issue though. Maybe the master or slave cyl are sticking on gearchanges, or maybe the clutch plate is too thin for the provided pressure plate (ie manufacturing issue)

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Disclaimer: I actually DO know everything

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Yeah i was actually just thinking before that the issue isn't how much clamping it has, but more like how long it takes to clamp.
ie when slamming gearchanges etc it just takes too long to push the slave back out.
so i'll clean out the system, maybe even get a new master/slave.

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1996 180sx
1990 Silvia

my old master is here not being used... was working fine.
ill give it to you for $40posted

or if u just wanted to try it you can if u cover postage.

the slave is here also but the rod was pulled out, so nfi if its fucked or not.

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formerly 3AM

The rod just sits there, so it doesn't matter if it falls out.
I think i might have an old master here too.
I might as well try a brand new one while i'm at it thought or put a kit through my old one.
I have two cars and a motorbike so no issues really if it takes a few days of the car off the road to sort it out.

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1996 180sx
1990 Silvia

I have the same issue with the 180sx at the moment. It occurred after the clutch was changed. I cant afford to have the car off the road so could you put a post up regarding the issue when you've fixed yours so i know what to try? Thanks

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Crush the cars of drink drivers...Don't punish those who go to the track

Pressure plate was too light, turned out to be 600kg not 800kg like it was supposed to be.
Putting in a different clutch.

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1996 180sx
1990 Silvia

What sort of clutch was it?

I have an exedy heavy duty cushioned button in mine. I found that the last few clutches from exedy have been slipping.

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Crush the cars of drink drivers...Don't punish those who go to the track