2G Brand new clutch slipping at anything past 3k rpm

[Dihtung Glava]

I have no idea what I could have messed up here, so after 2 days of trying not to pull the trans again, I'm asking the council. I put a new clutch between my 1g engine and 2g trans (I'm pretty sure the generations are irrelevant tho) and the engagement is absolutely horrible.

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It feels OK when the car is off and I'm pretty sure it disengages fully as well, but when I release the pedal, the bite only happens at the very top, almost at the last half inch of pedal travel. When driving, the awful bite point is bad enough, but the clutch also entirely slips at anything past 3k rpm.

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I still have about a half inch of threads left on the bolt that limits pedal travel but I feel like the problem has to be somewhere else because there's no way the clutch should only start biting that high.

I've bled the system from the master and the slave cylinder 3 times - the first 2 times I left the adjustment on the master as it was on the old clutch, and for the third time I twisted the rod all the way out.

I can compress the slave by hand and it returns to original position without problems.

Am I doing something wrong or could my new clutch be defective?

 

[99dsmer4g63]

Did you change the flywheel? Or is this the same flywheel that was used with the previous clutch setup?

What prompted you to change the clutch in the first place?

-Daniel

 

[Dihtung Glava]

I kept the same flywheel.
The clutch was old and worn but I didn't want to go full send on an ACT clutch just yet, so I just got a "OEM" replacement while I had the engine and trans apart. It was 50€ so I was happy but now I feel like I might regret it

 

[pauleyman]

Was everything clean? Did you machine the flywheel? Have you adjusted the master?

 

[MindBlowin03]

Maybe it's me but that pressure plate doesn't look like it's even the correct one for the car. It looks much deeper than it should be.

 

[curt-s]

You can compress the slave by hand after you do adjustment but try pumping the clutch pedal a few times, then see if you can still compress the slave.

 

[Dihtung Glava]

Was everything clean? Did you machine the flywheel? Have you adjusted the master?

I cleaned everything with brake cleaner before installing. I did not machine the flywheel. I have adjusted the master, I'm just not sure it's helping.

Maybe it's me but that pressure plate doesn't look like it's even the correct one for the car. It looks much deeper than it should be.

It is deeper than the standard eclipse pressure plate, the 6-bolt I am working on came from a galant, so it has a flat flywheel, without the extruded bosses for the flywheel bolts. The pressure plate is just as deep as the one that was there before.

You can compress the slave by hand after you do adjustment but try pumping the clutch pedal a few times, then see if you can still compress the slave.

Will do.

 

[donniekak]

Can you reach down and push the slave cylinder in by hand?

 

[CrackedDSM]

Is it a non turbo 4G63 clutch on a turbo 4G63? I know you euro guys had n/t 4G63 2Gs instead of the 420a we got.

 

[Dihtung Glava]

Can you reach down and push the slave cylinder in by hand?

I can. It compresses and returns normally.

Is it a non turbo 4G63 clutch on a turbo 4G63? I know you euro guys had n/t 4G63 2Gs instead of the 420a we got.

Yes. But I don't think the turbo is the issue if that's what you're getting at - the old clutch lasted years even with the added power.

 

[chrisman287]

I can. It compresses and returns normally.

Try adjusting the master rod until the slave can't get pushed in then adjust back a little until it can get pushed in. Having a someone at the slave while you adjust will help

 

[curt-s]

I can. It compresses and returns normally.

And that's after giving the clutch pedal a few full pumps as well? (ie. not getting pedal 'pump up')

 

[Kryndon]

To the US folks: This is a non-turbo 6 bolt which uses a non-stepped, entirely flat flywheel and a corresponding flat pressure plate. Off the top of my head I cannot recall the clutch disc thickness but I believe it should also be the same as the turbo discs, about 8mm new thickness.

To my buddy Headgasket, keep in mind a clutch can wear unevenly and wear the flywheel unevenly too. So much so that, unsurfaced, a new friction disc wont make full contact and will lead to the issues you're having. Flat flywheels also require machining IF they are found to be concaved or too worn. It's very hard to see with the naked eye, sometimes you can sort of feel it by running your finder over it.

What brand is the new clutch kit? It doesn't look like an Exedy since I'm not seeing any marks. If it's a Luk or Valeo you might as well toss it in the bin. Based on your photo, I would say the pressure plate fingers (diaphragm) are looking a bit too flat. As a new disc wears, those fingers go even flatter, which is when the hydraulic clutch system self adjusts and applies more travel on the clutch bearing. A good sign of a decent clutch setup is when those PP fingers are pointing ever so slightly outward. It may look insignificant, but it can make all the difference between full engagement/disengagement. This is why people have been saying, have the end of the clutch fork (the end sticking out of the bellhousing) to be pointing ever so slightly TOWARDS the clutch slave cylinder.

At this point I can recommend two things: First, redo the clutch master adjustment *by the book*, watch Jack's Transmission video or write to me on Facebook I can explain it in full detail to you. After you get that done and you can push the slave back with your fingers (and you haven't blocked off the pressure relief valve), test drive the car. If the issue persists, dismount the slave cylinder from the two bolts, remove the rod and insert something like a nut or something strong to act as a makeshift spacer to give it a few more milimeters of total length. THIS IS ONLY TO TEST, but if you regain full clutch operation and no slippage, then the issue is in your clutch travel and improper friction disc thickness.

 

[Dihtung Glava]

To the US folks: This is a non-turbo 6 bolt which uses a non-stepped, entirely flat flywheel and a corresponding flat pressure plate. Off the top of my head I cannot recall the clutch disc thickness but I believe it should also be the same as the turbo discs, about 8mm new thickness.

To my buddy Headgasket, keep in mind a clutch can wear unevenly and wear the flywheel unevenly too. So much so that, unsurfaced, a new friction disc wont make full contact and will lead to the issues you're having. Flat flywheels also require machining IF they are found to be concaved or too worn. It's very hard to see with the naked eye, sometimes you can sort of feel it by running your finder over it.

What brand is the new clutch kit? It doesn't look like an Exedy since I'm not seeing any marks. If it's a Luk or Valeo you might as well toss it in the bin. Based on your photo, I would say the pressure plate fingers (diaphragm) are looking a bit too flat. As a new disc wears, those fingers go even flatter, which is when the hydraulic clutch system self adjusts and applies more travel on the clutch bearing. A good sign of a decent clutch setup is when those PP fingers are pointing ever so slightly outward. It may look insignificant, but it can make all the difference between full engagement/disengagement. This is why people have been saying, have the end of the clutch fork (the end sticking out of the bellhousing) to be pointing ever so slightly TOWARDS the clutch slave cylinder.

At this point I can recommend two things: First, redo the clutch master adjustment *by the book*, watch Jack's Transmission video or write to me on Facebook I can explain it in full detail to you. After you get that done and you can push the slave back with your fingers (and you haven't blocked off the pressure relief valve), test drive the car. If the issue persists, dismount the slave cylinder from the two bolts, remove the rod and insert something like a nut or something strong to act as a makeshift spacer to give it a few more milimeters of total length. THIS IS ONLY TO TEST, but if you regain full clutch operation and no slippage, then the issue is in your clutch travel and improper friction disc thickness.

Well well well if it ain't Stefan!

Bro you have been helping me fix this car for like 2 years and I'm still not done somehow, that's crazy

Ok yeah, I guess I shouldn't have just left the flywheel as it was. New clutch is not Exedy, It's Mapco which is ... not much better than Valeo or LuK.

Thanks for the tips, I'll try everything and post again when I fix this.

 

[Dihtung Glava]

Ok, I've adjusted the master cylinder as per the Jackstransmissions' youtube video. I don't have a switch at the top of my clutch pedal travel like he and many of you do, there's just a bolt and a lock-nut, so I backed those all the way out - so the pedal had the maximum travel available. Then I did everything exactly as he did. The clutch does start to engage about a quarter inch sooner now, but that's entirely from backing the bolt and lock-nut the rest of the way out of the pedal assembly and it's still waaay too close to the end of pedal travel. The bottom half of the clutch pedal travel is not doing anything.

Kryndon, I fail to see how adding a spacer into the slave cylinder would help the situation, as I need the clutch to bite sooner, so if anything, I need a shorter slave piston, not a longer one. I did remove it just to see what I could do with the clutch fork by hand though, and It seems that when I touch the bearing to the pressure plate, the fork doesn't point towards the slave, its more neutral if anything:

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And this is the fork with the piston in place:

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it looks about the same to me...

You are likely correct in your assessment that the pressure plate fingers are too flat, because I feel like the bearing should be reaching them way sooner. So now I believe I've either installed a clutch kit that doesn't work with this transmission or I used too much grease on the fork and input shaft to where it's been flung onto the clutch surfaces and they don't engage as well as they should.

Either way it's looking like I'm gonna have to pull the transmission again to see.

 

[Kryndon]

If the slave cylinder piston(or rod) is theoretically longer, it will mean that you need less overall travel of the mechanism to get full disengagement. So if the issue was with not enough travel, that would have solved it to some degree, but it may also start preloading the bearing onto the plate fingers. Although on some cars, the TOB is always in contact with the fingers and always spinning, thus getting worn out sooner.

The position you have right now looks fairly okay, and your Paint diagram also looks correct. Your worry about excess grease being flung out is a very possible scenario which I've seen happen before. You only really need a slight dab around the splines. Some people don't even run any grease at all just to eliminate this potentially happening.

I think you should pull the trans out, measure the total thicknesses of your old + your new friction disk and also measure the heights between the mounting surface to the friction surface on both pressure plates, and report back. It's possible your new PP even though it's for a 4G63 N/A, could ever so slightly have different specs and needing a different disc. I really can't think of anything else, considering your clutch worked prior to all this.

 

[Dihtung Glava]

Well yeah, a longer rod would provide more disengagement, I agree. But I need engagement not disengagement. The bearing could very well be preloading the PP already. I can't imagine how a longer rod would make this better, only worse.

That said, you (and everyone else) were most likely correct in assuming the old flywheel is the problem. And I was also likely correct in my greasy clutch hypothesis. I finally pulled the trans and I saw this:

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I write "likely" because we won't know for sure untill I have the the trans back on, but these two pictures alone look bad enough to belive we found the problem.

I was an idiot and I just assumed the flywheel was good AND I put too much grease on the splines. Flywheel is at the shop as we speak and I'm deep cleaning the clutch plate just in case, I'll update this when I have the car back together. Thanks.

 

[Kryndon]

Yeh I'm stupid, I was thinking of the opposite problem about the clutch rod. You're correct!

Also yeah the flywheel don't look good at all, that's probably a good 0.2-0.3mm convex there. It looks like the grease almost reached the contact surfaces, but you might be lucky. Take a can of brake cleaner and spray the friction disc on both sides liberally then let it out to dry fully. This should take care of any residual greases on it.

Hopefully this will fix your problems this time. Oh and just a reminder even if you are doing it right, always torque the PP to the flywheel in star pattern in stages, as well as the FW bolts to the crankshaft!