Theories on Clutch Failure: Weird case

[takai]

Ok, so ive seen clutches go by overheating them, or general abuse, or rivets coming out, or slipping behind high HP/Nm cars, but this is the weirdest one ive found sofar.
Basically what has happened is that the entire friction material, on the gearbox side, has come off entirely. Huge big chunks of it were floating around in my gearbox when i pulled it off. There wasnt any visible foreign material in the bellhousing though.

Who wants to have a go at figuring out how it failed. Im leaning towards 9000rpm clutch dis-engages having something to do with it.Possible centrifugal force failure, maybe coming loose at one point and then the rest of it cracking and disintegrating around the rivets.

Pics here:

As usual, click for bigger.

[river]

Hi,

Possible centrifugal force failure, maybe coming loose at one point and then the rest of it cracking and disintegrating around the rivets

Yep... agree. Probably cracked or weakened in an area and the load and centrifugal force did the rest.

Poor manual gearbox/clutch skills technique - get an automatic!

seeyuzz
river

[takai]

Heh, 9000rpm isnt nice on components...... but yours should be fine river

[thechuckster]

or:
A - incorrect clamping pressure from rivets (e.g. doomed to failure)
B - heavily worn clutch, heat from use weakened rivets, rivet allowed movement, centrifugal forces did the rest

fwiw: the clutch from the last engine wilbo pulled apart has loose friction material on one of the clutch. But it was a lot more worn that yours suggests (e.g. unlike the left picture, there was almost no difference in height of friction material on wearing face and around rivets.

[allencr]

weak material countersunk too far, or too small a rivet head, or under or over rivited = loose from not enough pressure or material crushed from too much pressure on them.
disks are poorly balanced, if they're balanced at all.
How long did it last? I'm surprised that stock ones with rivets to that 'springy plate' last as long as they do. That
flexing on a single point of contact with a rivet that isn't just right, isn't going to last when worked hard/abused.

[takai]

Its an Exedy HD item, which i was originally only going to run until the car was sorted so i guess i was asking for it. The plate had only done about 500km max, and the material which is left is basically brand new, ill take new pictures tomorrow with my digital camera not my phone.
It could have overheated, but ive been careful with slipping that clutch, although a bit is inevitable.

[Vios-GT_07]

what diff are you using? locked in / mini spool things tend to do that to clutches..

[takai]

1.5way LSD, no locker here.

[jezza323]

my friend had a similar thing happen in his civic at a trackday, upon taking the clutch out there was no friction material left on either side of the clutch disc

they seem to reckon it was a slightly warped clutch disc to start with which caused the friction material to loosen from the plate and the 8400 rpm at the track on a downshift is what did it in...

it was a Daikin clutch plate btw

[YelloRolla]

Don't know the answer, though centripetal force could well be the reason (already mentioned by yo and River). I had the same issue on my 18RG HiLux a few years back. That car was continually power shifted, but let go on a down chage (with accompanying rev). It let go with the clutch pedal in (disengaged).

[gianttomato]

Slight hijack....I am bending the drive straps on the pressure plate on upshift (the usual is on downshift). Why???

[Vios-GT_07]

yea about that civic... i've shattered one in a civic, and this was from just driving normally..a bit of higher revs i.e. 3000 rpms to take off coz the engine was a retarded i.e. it was so underpowered for what it was.. timing was off or the belt was wrong.. something or rather.. anyway the second time i revved it up to 3000 to take off, the clutch went bang and shattered into pieces.. that Honda wrecker place who did the clutch reckons it was new, but when we pulled it apart, the friction plate was half worn down and everything was in pieces.. everything was cracked or broken.. was a Daikin clutch too..

[YelloRolla]

Slight hijack....I am bending the drive straps on the pressure plate on upshift (the usual is on downshift). Why???

The clutch was assembled incorrectly? It sounds like the drive straps are under compressive load rather than tensile.
Have you looked at the way load is being transferred through them?
I am assuming that you mean the straps that connect the clutch cover to the pressure plate.
Jase

[thechuckster]

seeing as nobody else has said it .. did you use the same clutch manufacturer as Skaife/Holden?

[IN 05 NT]

seeing as nobody else has said it .. did you use the same clutch manufacturer as Skaife/Holden?

AHAHAHA LMAO....sucked in holden fans!


i did a clucth 2 weeks ago on a N14 pulsar with fully sick airbrushing all over it,

we advisd her that her clutch will only last a few months longer, 2 weks later she came in with no drive at all, same thing, all the fricton plate was clean, and shreads of clutch material all through the box,

and earlier this week, same car we did the clucht on was towed back in, one of the pinion gears in the diff ripped a hole in the side of the box housing and spat selector shaft through the back aswell,
(supposedly common on N14 pulsars at around 250k....)

and im thinking my clutch went from my rear main oil seal leak, as it was getting bad, and was high priority on the fix in the next week,,,,,but it killed the clutch first but i'll confirm that when i get the clutch out...this week!

blake