Alright, so this is partially a diag thread, but most likely an autopsy. I was at the track this weekend and towards the end of the day I had a hard time getting the car into gear. I got to the pits and let the car cool down a bit and took the car back out. A couple laps later I had no pressure on the clutch pedal until I was about 1" off the floor. I pumped the pedal and got back into gear. I limped the car back to the pits but was unable to get the car into any gears with the clutch pedal pushed in. I can fire the car up in neutral and when I go to put the car in gear I do notice that the car tries to move forward a tiny bit but the shifter hits a wall.

I figured the clutch had died, but the plunger is still moving the clutch fork. I didn't have any fluid loss but bled the slave anyways hoping to have a quick fix. No dice. I also checked the clutch pedal adjustment and everything was tight there (IE the jam nut had not slipped).

Here's a video of the slave plunger moving. This was even before I added fresh fluid.

I've got a new master and slave cylinder showing up tomorrow, but I have very little confidence that they're going to do anything.

Just curious if anyone has any ideas about what might have gone wrong or possible further diag before pulling the trans out. I'd love to finish out the autocross season with the car, but assuming the clutch and/or pressure plate are toast I don't see that happening (FM Level 2 is out of stock until the season is over).

Also, I will note that the pedal feels completely normal now and that I have beat this clutch pretty hard. The past month or two have seen it right at or over it's rated torque figures (VD estimated ~280 WTQ) and I've been running it for about 3 years total. It's probably seen ~8K NA miles and ~15K boosted miles and plenty of autocross launches. I've really enjoyed this clutch but knew I'd be pushing it taking it on track with this new turbo.

 

That really reads like textbook hydraulics failure, and not the clutch itself.

In my experience clutch failure has bad rotational noises, slipping under power, ever-narrowing window of engagement, and/or outright disintegration. I have seen hydraulics fail and not leak externally, where they keep the fluids in but simply fail to build pressure. I’d wager your new hydraulics will solve the issue.

 

I’ve seen tons of fm1 failures, the plate fails at one of the spring pockets. Whether or not that’s what youre experiencing i dunno. I don’t typically see clutch hydraulics “come back” when cooled. Once the pedal is low it stays there, sometimes you can rapidly pump it up for another engagement or two, but I’d be looking at yanking the trans.

 

The fact that the slave plunger seems to be operating normally makes me think that the hydraulics aren't the issue. Curly, I was figuring the same thing, it doesn't seem like system from the pedal to the slave cylinder would operate normally if there was an issue with the slave or master. I'll likely replace them anyway since I don't know the history of the ones on the car, but I assume the trans will be coming out in a week or so.

 

That is a good point, I somehow missed the video earlier. FWIW my SuperMiata has been fabulous though plenty of abuse, bigly recommend. I’ve heard nothing but trouble regarding the FM suite of clutches

 

I haven't had any complaints about this clutch up until this point. I'd happily buy another if I wasn't pushing the power limits of this clutch. If I hadn't heard multiple people (both on the forums and personal friends) complain about the street manners of the SM clutch I'd go with that. Considering I drive the car ~8K street miles each year that's pretty high on my priority list.

I was reading around about how to unstick a clutch. I have no idea if any of those methods are applicable to my situation, but I think I'll try a couple and see if I can free up the clutch somehow. If those don't make any improvement then the trans is coming out. Either way I planned to pull it this winter for a new clutch and possibly some trans work, so it's not the biggest disappointment aside from missing a couple events.

 

Oh interesting, I haven't heard any complaints about the SM clutches. My sport/full face one is essentially invisible, I don't think I'd pick it out if I didn't know it wasn't an OEM one. Not sure about the puck version though. You are kinda right at the limit of the full face one though, they rate it at 290ft-lbs.

 

Curly I think you nailed it.







This thing was just falling apart. I think one of the spring pockets is still intact.

Apparently this is the same disk that the level 2 uses, just with a different pressure plate. It also sounds like FM went to a different supplier at the beginning of the year, so hopefully this issue isn't present in the new clutch I just ordered.

This seems like a manufacturing issue to me but I'd be curious to hear other opinions. I was running the clutch towards the limit of it's quoted torque, but I would expect it to slip before it split in half.

 

Oof, yeah that is brutal! I also would have expected it to slip before ripping the spring pockets apart. Honestly it looks like you still have a decent amount of the friction material left on there too, given being at the bleeding edge of the torque rating and the length of time its been subject to that torque. I was def wrong on the hydraulics issue, it looks like that one spring that's tried to escape was rubbing on something, which probably explains the lack-of-disengagement symptoms.

 

Yeah I think it was rubbing on the pressure plate. Most, if not all, of the springs had evidence of rubbing/interfering on something. You can see the scoring on the pressure plate here.




Even the other side of the clutch showed signs of rubbing and have missing material around the spring pockets.

 

I would just like to mention that I have moved to the Supermiata ceramic 4 puck clutch this year, and so far, I love it. My 1.6 is currently making about 230 rwhp. I have done some autocross days and a lapping day where I got about 2 hours of track time on it, as well as a 3,000 mile road trip and several thousand street miles. It does make a little noise when starting from a stop some of the time. The feel is great, launches are great, shifting and pedal effort are great. Engagement range is more sensitive than the organic Supermiata clutch that I burned out on an autocross day earlier this year. But you can still get clean smooth shifts whether cruising in town or running it to redline without jerking the car around. So far, I am a big fan of this one. I just thought I'd add this positive comment to the conversation.

 

Local Miata shop here in DFW has noted numerous FM clutch failures as of late, has stopped installing them all together from my understanding. (Even if customer supplied.) I would assume it is a supplier issue as well.

 

Dang now I feel vindicated in buying an ACT instead of an FM. (Now please don't dog pile me saying the ACT's do the same thing or something like that lol)

 

As a shop, we’ve seen a decline in ACT quality. I still recommend them because typically they’re broken out of the box, simply not disengaging or similar, so you can get them replaced easily.

 

exactly my opinion

 

Oh that's a much better way to be. Mine's been good for probably 3k miles so I think were good.

 

Those FM1 failures are notorious for cracking at the spring pockets. Your symptoms sound more like a hard failure usually, when hydraulics go out, they don't magically come back. If it was me, I'd be planning to pull the transmission to get a better look.

 

Pretty sure this Prosprom guy is a bot. He's just regurgitating previous comments.

 

Lmfao, the bots are getting weird now days

 

lmao even tm.net has bot commenters now

Edit: Lol look at his page his Miata is a "Turbo + Nitrous Mercedes"