My clutch is slipping again.

[v6buicks]

It sounds and feels like I'm about to roast through clutch #3.

According to the SPEC website, my clutch is only torque rated to 417 which is just barely above what I'm making. That's not good. On top of that, it recommends a break-in period of 450 miles. That sounds like pure insanity to me. 450 miles of break-in would probably not take too long if I still lived in Lisle, but I can't go anywhere in Indiana without long stretches of highway or interstate. I think I only drove it about 200 miles before I started giving it short bursts of WOT, and it honestly felt fine until after the dyno when I finally started giving it the business.

I was in denial until now, but installing the shifter and actually rowing through the gears at WOT helped me realize that my crappy 215s are not what's causing the squealing. Am I not being patient enough with the break-in? Whatever it is, I'm tired of pulling this T5 out. I might as well have a 4t65e. What clutches are manual 3800 guys with lots of torque using? I saw that RAM offers a couple dual friction units that should be up more than up to the task, but their rating is in HP which sounds irrelevant to me. Spec offers two clutches rated higher than mine, but I'm hesitant to try more clutches from the same brand of stuff I'm having trouble with. Even then, I'm not entirely convinced that the clutch is the soul problem. Is break-in super critical? Is there anything special I need to do to set-up my hydraulics besides bleeding? Is there any reason to upgrade to adjustable stuff?

I feel defeated. Was this car not meant to be or am I just progressing the engine further than the clutch is able to keep up with? I'm kinda just ranting here, but I'm open for discussion in case I'm doing something dumb during my break-in and installation which honestly just entails torquing the new parts down without any measurements and then going for a couple hundred miles of soft driving.

...sometimes, man. I wish I could strangle a car.

Click to read more...

 

[10sec]

If you didn't break the clutch in long enough, the pressure plate/disc/flywheel might not have full contact with the clutch material and could be slipping. Where is the release point of the pedal? High? Low?

Ideally you don't want to be at 95% of a clutch rating 100% of the time. You want to be at like 60% if you want the clutch to last. Then you gotta figure out if you have enough clamping force or you need a more aggressive disc for a higher TQ rating to last longer.

You also have to make sure your clutch is actually slipping. Usually a super high load like a 4th gear pull from a low mph will test the clutch the best, if it slips during that pull then, yep you're pull that T-5 again.

 

[v6buicks]

If you didn't break the clutch in long enough, the pressure plate/disc/flywheel might not have full contact with the clutch material and could be slipping. Where is the release point of the pedal? High? Low?

Ideally you don't want to be at 95% of a clutch rating 100% of the time. You want to be at like 60% if you want the clutch to last. Then you gotta figure out if you have enough clamping force or you need a more aggressive disc for a higher TQ rating to last longer.

You also have to make sure your clutch is actually slipping. Usually a super high load like a 4th gear pull from a low mph will test the clutch the best, if it slips during that pull then, yep you're pull that T-5 again.

The clutch releases pretty high in the pedal travel. I'll try paying more attention to that on my way home.

Good to know! I'm definitely pushing this one beyond the limit according to my wheel tq numbers on the dyno compared to what I assume to be a crank tq rating on the clutch. As for the slipping thing, I guess I would have to take the interstate home to try that. I am generally noticing this sort of thing after downshifting into second and letting the RPMs get up over 4k. When I shift into 3rd around valve float and punch it again the squealing resumes immediately. I've even turned around afterward to look for tire marks. Negative. lol I'll try the 4th gear thing you mentioned. That sounds more controlled, since I know that the tires shouldn't spin. I just assume that it's going to grip and bog because this car is not very strong at low RPM. We'll see though.

 

[10sec]

You have a scanner, log the RPM vs MPH. If the RPM is going up and the wheel speed isn't, the clutch is slipping.

You want to be at 100% throttle before the turbo spools, because once the turbo spools to full boost that area and a little beyond is usually where the peak TQ is and if the clutch is legit slipping it will do it at that time in a high load like 4th gear. You don't have to go much past the peak TQ, so you shouldn't revving it out all the way in 4th gear. You just want to get through where the peak TQ is to see if it'll slip.

 

[v6buicks]

You have a scanner, log the RPM vs MPH. If the RPM is going up and the wheel speed isn't, the clutch is slipping.

You want to be at 100% throttle before the turbo spools, because once the turbo spools to full boost that area and a little beyond is usually where the peak TQ is and if the clutch is legit slipping it will do it at that time in a high load like 4th gear. You don't have to go much past the peak TQ, so you shouldn't revving it out all the way in 4th gear. You just want to get through where the peak TQ is to see if it'll slip.

Got it. Makes sense to me! I'll wait until I get home and hook up my laptop.

 

[v6buicks]

I didn't even get a chance to plug my computer in. The clutch is done. No more boost for me

Time for another downer build thread update. lol

 

[10sec]

Are you sure it is the clutch? Not a slave? Not a CMC? Unless that clutch was slipping the entire time you were driving it, I can't imagine it wore out that fast.

 

[v6buicks]

Are you sure it is the clutch? Not a slave? Not a CMC? Unless that clutch was slipping the entire time you were driving it, I can't imagine it wore out that fast.

I have no idea how to diagnose or fix any of that, so no. I'm not sure.

 

[10sec]

Well then how do you know the clutch is fucked? My friend, this is 2020. Hop on youtube for an hour or so and watch some videos about how to diagnose a slipping clutch. A high pedal release is most certainly a symptom of a bad clutch, but it could also be bad CMC adjustment and not letting the clutch fully engage.

 

[v6buicks]

Well then how do you know the clutch is fucked? My friend, this is 2020. Hop on youtube for an hour or so and watch some videos about how to diagnose a slipping clutch. A high pedal release is most certainly a symptom of a bad clutch, but it could also be bad CMC adjustment and not letting the clutch fully engage.

What's there to adjust though? It's either bled or it isn't, right? All the parts are stock replacement, so they get tossed in and that's it.... or at least I thought. Mechanical stuff would be a different story of course.

 

[lefty]

I love my McLeod, but it's on a t56

 

[10sec]

What's there to adjust though? It's either bled or it isn't, right? All the parts are stock replacement, so they get tossed in and that's it.... or at least I thought. Mechanical stuff would be a different story of course.

After installing a clutch you need to adjust the clutch pedal for proper engagement. There's tolerances for how much free play is in the pedal before it starts to disengage the clutch. Should be specs for your car, you might be able to google them or have to buy a cheap downloadable factory service manual.

 

[v6buicks]

After installing a clutch you need to adjust the clutch pedal for proper engagement. There's tolerances for how much free play is in the pedal before it starts to disengage the clutch. Should be specs for your car, you might be able to google them or have to buy a cheap downloadable factory service manual.

Ahhh... hmmmm.... Yeah, I didn't do anything like that. I ASSumed that the being hydraulic everything was self adjusting kinda like brakes, so I guess there's that.

Now that you mention it, I forgot that my pedal box is actually broken. The pedal returns ONLY via hydraulic pressure. The spring broke and fell out which is kinda sketchy. I have a factory service manual. Hopefully, it'll enlighten me on what exactly I need to do. Thanks!

 

[10sec]

The hydraulic part is after the pedal is adjusted it wears and stays in the same spot. Kinda like brake pads, the pedal doesn't keep moving down, it stays in the same spot. If your pedal was a high release this entire time it probably wasn't releasing the pressure plate all the way and just slowly overheating and wearing out that clutch.

 

[v6buicks]

The hydraulic part is after the pedal is adjusted it wears and stays in the same spot. Kinda like brake pads, the pedal doesn't keep moving down, it stays in the same spot. If your pedal was a high release this entire time it probably wasn't releasing the pressure plate all the way and just slowly overheating and wearing out that clutch.

So I looked at the manual which sparked an old memory. The first clutch I removed (original) had adjustment tabs on them. The manual says that these are supposed to be reset with the installation of new clutch disks. I have nothing like that anymore.

I have no idea if that has anything to do with what's going on but a Google search shows that this is an issue for both LS and V6 F-bodies alike. There is no pedal nor hydraulic adjustment so the shitty high disengagement is just just what you have to deal with after a pressure plate replacement. Apparently all replacements are this way, but it's much more apparent in performance pressure plates. Greeeaaaat!

I hate GM more and more every day. I'll read up some more about this tomorrow while I count my pennies.

 

[Mattstrike]

If it makes you feel any better, which it won't, my SC Camaro is once again reaching rape point on it's clutch #2. #2 was slipping hardcore in 3rd and 4th in the mountains on Power tour last year (#2 was a used clutch from a rando that looked good, so full send it.). It seems like it finally bedded in at the beginning of this year, but the weight of my foot on the clutch is still enough to make it slip. Just don't rest your foot on the clutch.

 

[v6buicks]

Thanks for the insight, guys. This was helpful. Using a combination of info from you guys, the FSM, and old LS1tech form posts, I think I've found a solution that makes sense.

Tick Adjustable Master Cylinder

It's pricey, but I think it would greatly help with clutch longevity, grip, and drivability. Mattstrike mentioned the thing about resting my foot on the pedal which I know is a bad habit of mine. This car's pedal is just so dang high off the floor that removing my foot and bringing it back to the pedal becomes a chore. I didn't understand how a master cylinder could be "adjustable" until I read the directions. It sounds to me like the whole unit is just over sized, so shorter pedal strokes yield more hydraulic flow. I like the sound of that. There should be plenty of room in the master for self adjustment in the slave (assuming that it too is not maxxed) while also keeping the pedal at a comfortable location.

 

[v6buicks]

So my clutch isn't slipping anymore, but I am considering some changes while I do the trans swap. The Spec stuff freaks me out. Trashing their "Stage 1" in a matter of a couple hundred miles with relatively light driving and reports of rivets coming loose do not give me happy feelings with my "Stage 4". Has anybody had experience with Clutch Masters? I'm kind of shocked that they even have fun stuff for 3800s.

 

[GTPpower]

Have you asked Jeff kuntz what he runs? He's fwd, but makes more than 700whp through a manual.

 

[v6buicks]

Have you asked Jeff kuntz what he runs? He's fwd, but makes more than 700whp through a manual.

I have not. I've seen him on Facebook though. Thanks for the tip.

 

[10sec]

Clutchmasters is

A lot of s2000 owners with superchargers use that brand and have very good luck with reliability and function. In the s2000 world a lot of clutches are junk, there really is no other aftermarket reliable option.

 

[v6buicks]

That's good to know. I'm hearing a few people say that they're a good brand, so I feel good about trying them next time.

I started this thread a while ago with the assumption that performance clutches will be rated for certain power levels. I'm starting to understand that this would be pretty tough to do since the holding power greatly depends on driving style and the type of abuse the car will experience. Is it kinda like brake pads where certain materials are only good for racing? Why would I want the segmented vs full kevlar disk? Will the full disk last longer while the segmented grips harder? I assume like brake pads the ceramic disk will not do too well in a street application, but I'm a newbie.