Hey guys, so I just ended up with an Exedy Triple disk and spoke to a local shop that is saying or suggesting I need to upgrade the trans input shaft to a billet option. Is it common for these clutches to damage the splines or brake input shafts? I have also read of these clutches damaging thrust bearings. Basically I'm just trying to see how many have used these under high torque situations without having to modify the input shaft or thrust bearings. This unit will be used on 2.3 6466 evo somewhere in the 800whp range.

Thanks in advance

 

Bump

 

The issue with the exedy triple disk clutches (latest version at least) is that the center splined hub that mates the transmission input shaft to the 3 friction disks is made out of a softer metal than the teeth on the disks. It results in wear of this hub over time which is what exedy did on purpose to prevent damage to the input shaft.

The problem originally showed its face when the exedy triple did not have that adapter hub yet and a slight misalignment of the transmission to the clutch assembly, often times caused by missing dowel pins or bell housing bolts, would cause all the teeth to sheer off over time. This was particularly apparent on the top disk of the clutch. It also doesn't help that the clutch friction disks are unsprung and evo's do not have a pilot bearing to hold the other side of the input shaft steadily in place.

That being said, I am using the exedy triple disk on a shep trans with oem input shaft.

-pal215

 

I dont think anyone is making a billet input shaft. and I dont think it would help. I also dont think there is much good info on why the splines wear. although I do think there is quite a bit of bad info. so here are my observations and theories.

I dont think the problem is a metallurgy error on the part of exedy. Its pretty simple to measure the hardness of the input shaft splines and then make the hub splines the same hardness. every clutch of every type ever made has to have this hardness match correct. and I believe it is. I would buy it possible a batch of hubs missed the hardening process. But I dont think thats the case here either. This is a problem that has not been solved with this clutch. The problem was just worse on the early version clutch. the early version has three separate disc splines, one for each disc that rode directly on the input shaft. this design just has too little spline material for each disc. the current version has one common hub that eliminated the small spline issue, but didnt solve the issue at all. it just slowed the process down.

I also dont think its an alignment issue. the flywheel is flat. so clutch discs would always self center/ self align with every shift. there would never be any pressure put on the splines . if the input spline was not centered perfectly to the flywheel then the discs would rotate off center clamped to the flywheel but centered to the input spline.. this would leave an out of balance problem that would be hard on main bearings. but would have no effect of pressure on the splines. leaving dowls out doesnt cause a misalignment issue anyway. it just allows the bell to fret back and forth on the bolts. which would quickly get worse and possible work the bolts loose.

the problem is harmonics from crank get into the discs of this clutch. BAD. that is apparent quite clearly from how loud this clutch is. I have not heard a clutch that rattles more than this one. its freaky loud. the noise you hear is a jack hammer effect working away at those splined connections. My theory would be pretty simple. The flywheel is of poor design and is not absorbing enough crank vibration. it simply passes straight through to the discs in a big way.

If you use this clutch dont expect it to last long. period. my advice is stay away.

 

Wow I really appreciate the knowledge and advice fellas. I purchased this clutch with the understanding it was a twin disk. The selling sold it to me for 200$ cash because he didn't know the condition or what he was selling. Upon receiving I found that it was a new style HD triple disk missing 1 disk but including all 3 plates and everything else. Also after measuring the remaining two disks I came to find they are almost new at 3.94mm. With that being said I figured I would purchase a 3rd disk and give it a shot. I would absolutely love to get a quartermaster 8 leg.

Also my usage with mainly consist of 1/2 mile racing and rolling pulls. It will rarely be launched or even driven light to light. Simply a low mileage race build.

 

Also what do you think about polishing the splines both on disks and the hub where they mate? I read that Jacks trans recommended doing so. If anything it sounds like this system just has to much play already and it's creating shock under engagement. Polishing would reducing binding but would probably increase the play.

 

Leaving dowels out definitely causes misalignment. Ask @kaj lol

 

Purchase a disk, and sell the clutch for a small profit.


Its not the splines that need polished, its the tower of the clutch basket. I had to this with my twin.

 

I learned after destroying only one transmission LOL. Just missing one dowel probably allowed the whole trans to rotate 1/8" in either direction; who knows how many degrees. Man, what a frustrating mess that was. I could only imagine how far off it could get with NO dowel pins.

 

Ive had the Exedy triple in my car for the last three years. Never had any issues with the center hub wearing or an input shaft issues. Just noisy as hell is all lol

 

How many miles on it? Time means nothing to mechanical parts, mileage is all that matters.

 

I feel like shifting too violently and not slipping the clutch enough during a launch is what breaks these clutches. I will be testing this.

Also we must keep in mind that when we use the clutch alignment tool, we can't just let it hang off the hole in center of the flywheel. It must be physically lifted due to the weight of the disks in the assembly to achieve true center. The installer has to do some active, visual centering before torquing down the pressure plate allen bolts otherwise there can be some bending of the disk hubs even before the first start up when torquing down the bell housing bolts. Pressure on these disks doesn't get released until the first time the clutch is blead after install. That can be minutes or days depending on when people stop working on the car.


Tom from TScomptuned has had a great experience with the exedy tripple with over 50 launches and hard street driving.

English Racing also has many customers who run the tripple without issues, one who daily drives it and drags it making more than 850hp.

It's not a coincidence that this clutch seems to be working for people who have a ton of experience in the evo world.


For everyone reading about this issue for the first time,
This thread has both the success and horror stories behind this clutch. It also shows a competition clutch failure.

https://www.evolutionm.net/forums/ev...before-15.html



-pal215

 

I think the issue comes from cruising the car around. When the disc and input aren't positively loaded because the car is cruising at a constant speed, harmonics and torsional whip just beat the splines/hub to death.

 

You guys are awesome, thanks for the thorough feed back. I can see how a violent launch or even just day to day light to light driving can start to wear the splines. I will be using the clutch on a 800-850hp 6466 set up souly for 1/2 mile racing and rolling pulls. It will not see anymore than 200-300 miles a year tops. When launching seldom I plan to leave off the handbrake there for pulling any slack out of the clutch and drivetrain before completely realeasing the clutch.

 

I appreciate the alignment advice, makes total sense. I will center it while having a friend snug the Allen bolts.