This has happened to me as well. But it was on a Competition Clutch i had bought from Map performance. The splines were a bit worn, but the whole spline hub had ripped out, making the new 400 mile clutch disc look like a donut.


I wonder if it was due to the pressure plate as well. (even though it was a push-style pressure plate)

That is the reason why i switched from Competition Clutch to Exedy, and I never use Map for anything anymore.
Im GLAD EXEDY TOOK CARE OF OP!!! Let us know how it drives and if there are any power increases with your new adjustments!

 

all the above


i believe it has more to do with improper install bending the input shaft than anything else & the fact that your only seeing it on the triples & non sprung disks is that they are less tolerant of the vibrations & stresses, this is the same reason you see all the hubs showing more damage on the outside disk & less damage as you move inward on the shaft, because any bending of the shaft will be more pronounced at the end

 

@ FX11

I was damn close to that happening to the disks in my QM twin.

https://www.evolutionm.net/forums/ev...lure-pics.html

 

there were no signs for me car drove like normal all day. I did one pull before i got to my house wastegate spring 18 psi on a hta3586 got to the stop sign and went to take off and the car wouldent move i noticed right away that the clutch was really loud when i pushed it in the disk sounded like they were grinding or rubbing each other and the car would also die slowly whenever i pushed the clutch in

 

at least you got some use out of them. I got less than 400 miles and pissed away more than $3,000

 

Has this happened with anyone using the push style exedy?

 

Seems like the multi plate clutches SUCK anymore.

 

You guys should see my Carbonetics triple. The guys at Carbonetics couldn't believe that I could still drive the car. I'll be starting another topic but G'Damn.

I got a few people saying I need to rebuild it but is this a multiplate clutch issue? Waiting on parts replacement cost and to see if my transmission is damaged.

 

Steve Fox from PTT told me years ago that a clutch that destroys center hubs has an alignment problem of some sort. He said since DSM/EVO does not use a pilot bearing you have to be sure your input shaft support bearing is good and that the alignment of the bellhousing to the center of the crank is correct. Some cars tolerances may be furthur off where the dowels are located and placing higher loads on the input shaft and hubs. Make sure your input shaft is centered and also make sure the dowels on the block are properly aligned. If needed you can machine the block and trans by moving the dowels to make proper alignment. It is very difficult to do however and not cheap. Does Shep make a stronger input shaft or could he make one that uses a pilot bearing to help with this issue?

 

I disagree with a couple of your statements. one it was very easy to leave rear bolt out of dsm leaving the trans with only three to hold them together. the trans would pull away at that one missing bolt point putting angular pressure on the splines. I dont think that is happening in evos. its not a bolt left out issue. misaligned dowels may be the issue. but i find it hard to believe there are that many poor installations in such a short period of time and only on exedy triples?. if dowels were not used this would be different problem that "bent" input shaft (three bolts would mimmick bent shaft) the shaft is still straight just rotating non concentric. the result would be all three discs showing wear pattern.

I have a huge problem with bent input shaft as diagnosis. It virtually impossible to bent input shaft. even if trans jack suddenly slipped away leaving entire trans weight on input shaft that would be no where near enough bending force to bent the input shaft. clutch discs are not stiff enough and simply would flex. if that is what was happening then all clutches would be affected. not just exedy triples and QM twins.

simple facts here are all triples have accelerated disc wear on the first disc. this common on all triples of every make. even when everything is working as it should. this issue is most likley a metallurgical problem. this clutch has had great feedback for quite sometime. the problems now are from recently used batches.

I do believe stripped splines on any clutch is result of dowels not being aligned. its a common mistake to reinstall trans with one or both dowels stuck in trans side. this is a mistake. BOTH DOWELS NEED TO BE IN ENGINE SIDE. they are not long enough to do their job when they slide to trans side.

 

i hear what you're saying, but in my situation the trans had both dowels. i actually have a few extra head, T/C & Trans dowels in my toolbox for just such situations. i know shep & tre will replace dowels when doing a rebuild, but if they were loose enough to cause an alignment issue i wouldnt expect them to stay in the bores. so i don't think its a dowel problem, least in my case.

Clutch was brand new out of the box

i did not disassemble the trans & diagnose the bent shaft, it was sent out to Shep & we all know he is a stand up guy & more than qualified so i doubt he was dishonest or misdiagnosed the problem. the trans was reassembled with a new shaft, had the worn clutch parts replaced, was sent on its way & has not had problems since. (customer is a friend, so i would have certainly heard of it.

given the low mileage these failures are happening within, it makes sense you wouldn't see much feathering on the disks. the one i posted had 1,000 on it & it sounds like others are around 2.5-3,000 max

the reason the QM & exedy are seeing more of these failures is that they use thick solid metal for the disk while standard clutches use rivited thin steel as well as springs to absorb torsional loads. the thicker heavier plate is less flexible & tolerant to bending as well as transfering more of the vibration & movment of the input shaft to the disk


also, from what i've seen. hanging a trans on the input shaft without supporting it properly is enough to bend the shaft, as well as the disks. particularly when people start "bouncing" it around because it got hung up or get the trans halfway on & take a break/RTFM etc.. because it "got stuck" the shop manual even states this as well as the instructions included in every clutch ive installed. ACT (i think) even has a nice saying on there instructions "dont hand your results on us" with a pic of the trans hanging on the clutch.

if it was a dowel issue, i would expect to see similar levels of wear on all three disks/areas of hub. the fact we are seeing the damage become more pronounced at the end if the shaft again points to a bent shaft in my opinion.

 

my triple is still good, but i do remember something different when installing vs my twin. When you lined it up with the clutch alignment tool and let go of it, it would sag down.. making it be slightly off center.. is this what you guys are talking about when you say bad installation? i had to make sure mine was dead on which took me 2-3 trys to get it there just right.. even took pictures of it to be sure of it.

so if one would install it with it slightly sagging off center is this whats causing it to chew the splines?

 

discs can be slightly off center during install. they center themselves as soon as pressure plate is released. at that point the discs are floating.

if input shaft is not centered in flywheel. the clutch disc splines will bind on the shaft as flywheel turns when clutch is engaged. the binding will heat the splines till they loose their hardness and then the teeth easily strip off.

 

oh ok. couldn't you avoid the uncenter stuff by rotating engine after its installed before starting? or are you referring to actual transmission damage where the spline is off centered due to transmission being bad?

 

well i found out what happen to my clutch. I spoke to a exedy rep and sent him the pics the disks i had in mine where the older style the kind that did not use the splined hub (the vendor i bought my rebuild disks from never told me ) the material that sits on the input shaft is softer and will fail sooner or later if you can dont down shift it will prolong the life of the disks alittle if you have the older style disks like mine replace them now so you dont end up on the side of the road.