both disc stripped and along with ti took out the teeth on my input shaft

 

****ty man....i thought those were decent clutches...

 

Dan that sucks I hope they make it right for you , those clutches are too expensive for that **** to happen

 

their good clutches .. but installation is very crucial .. even if you install it the way they sent it .. it will fu*kup .. one of my discs was slipping just before i took it out.. you do need to reshim them yourself before putting them in...

it really sucks that it took ur input shaft along with it sorry to hear ...

 

worked perfect for over a year and the crap. install went perfect check clearances everything was good so i dont know went wrong. just read on LS1 tech that it happened to a few guys a couple months ago also. and they told him that it was installed wrong, so he got it installed at a shop they recommended and it did it again. so they told him he doesnt let the clutch out sat a high enough rpm wihich sounds stupid to me

sounds to me like they just wont stand behind there product. i dont see any reason why the teeth on the disc should let go like that. i wouldnt recommend one. especially if it has happened to other people. there seems to be a lot more people complaining about them lately. or maybe im just pissed off still

 

I see alot of complaints on ls1tech, the corvetteforum, and z06vette about the LS1 McLeod twin. Same with the new Exedy clutches.

In fact, I have found no single clutch that hasn't had multiple failures. The Spec 4 and 5 clutches seem to have the fewest complaints from what I have been researching, yet they are also the least driveable.

 

Sorry to hear that Dan.
What it comes down to is that all your power has to travel through the splines on the input shaft. Going from a 11" clutch down to a wee little 1.5" input shaft is a major leverage reduction and results in MAJOR torque on those poor splines/shaft. On a single disc clutch there is about 1"-1.25" of spline. On a dual disc there is only 0.5-0.75" of spline for each clutch. In a perfect world it wouldnt matter because both clutches would engage at the EXACT same time but they dont in our world. So now as you dump the clutch and all that torque enters that thin little 5/8" thick spline for an instant while the 2nd clutch is still slipping. Whammo, bent or stripped splines. An incorrectly shimmed clutch only adds to this effect (not saying it was in your case). Dual discs grip well but they do beat the **** out of your input shaft which is why they are generally not used on street cars.
I would rather frag a clutch than an input shaft so I dont like dual discs unless there is a space limitation (or if I were rich).
Good luck getting it back together Dan.

 

gonna try and get pics up on monday, but it looks to me like the clutch let go and after the teeth broke they wor away at the input shaft. supposedly the teeth on the clutch are stronger then then shaft but aparently not. anyways i still cant get ahold of mcleod but we'll see hopw it goes tryin to get them to replace at least the discs

 

Sorry to hear it. I don't know enough about manual clutches to have an opinion, but it doesn't sound like a cheap dilemma.

 

that sucks to hear, i was never a fan of the mcleod street twin to begin with. personally for the street i would have prefered a lt4 PP with a mcleod single disc.

 

Cory, I hope you know that two disks is easier on the input shaft, think of it as spearing the load over two areas on the input shaft as aposed to one concentrated one.

What I think happened by the sounds of it is the disk teeth broke off, then the clutch would fall on the input shaft when released and just eat away at the teeth on the input shaft, now for that to happen when you have 2 disks would have to have some cheap material on the disks themselves.

Although you are talking big disk to a small shaft, you are not factoring in that the actual grip area on the disk (teeth) is much smaller then the input shaft, no way in hell would the disk be stronger unless its made of some crazy steel I dunno, thus why they broke and just grinded away at the splines on the input shaft by the sounds of it.

The trick is what Spec does LOL, sure you hear of their disks failing sometimes, but heck you notice how the center hub of the disk is only attached by small tangs to the actual contact area? I would think it is made on purpose so that in any event, thos fail and the hub stays in tacked still connected to the splines on the input shaft, the car will not move but atleast you don't have somthing wearing on the input shaft because the teeth on the disk to the input shaft broke off instead.

BTW I have no complaints thus far. You also have to account the weight of the assembly, when you shift at say 7K RPM, what is easier on the teeth, a 70LB weight flinging around or a 30LB weight which is what a normal set up is? I say if you go Mcleod go with the alluminum version, whether you decel hard by popping the clutch or power shift, the less weight the less stress on everything, so you miss the big hit when you do it, who cares it doens't make you go any faster.

 

matt .. the alum flywheel doesn't sit on the input shaft therefore the weight of it makes no difference .. I see what cory is saying about the dual disc clutch .. never thought of it that way ... but then again .. mine held together when i popped my clutch at 5000 rpm on the ET drags spraying a 150 shot ... that's over 500 rwtq ... anyway . wish u the best of luck dan..

 

Actually matt, I dont know that. What I do know however, are simple physics. You cannot fit 2 clutches in the space of one without reducing the surface area of the splines. The whole 2 objects cannot occupy the same space thing. So you have to 1/2 the thickness of the splines to fit 2 in. 1/2 the thickness is 1/2 the surface area. 1/2 the surface area makes 1/2 the strength (assuming materials are the same). How is that even remotely better for the input shaft? Its like cutting 2" off your driveshaft yoke and wondering why your output shaft stripped.
http://para.noid.org/~lj/T56/images/inputshaft.jpg
Thats what dual discs do to input shafts. Notice the 2 skinny *** rings where each disc has rounded over the splines. On a single disc is would have to round both those, and the part in between.

The weight of the unit doesnt affect the durability until it is spinning fast enough to grenade from centrifugal force. A GM V8 isnt going to do that.

Again, you should do some more research. The clutch friction surface is 10-12" further out than the input shaft. That 10-12" of more leverage. Simple physics say that the longer the distance from the centre, the more leverage and the more force is applied. This is why driveshafts are 3" wide and not 1". Same reason why race cars have large rotors, more leverage means more stopping power. The reason friction surfaces fail normally is because they see more heat, and are not a peice if solid steel. Now you have a VERY large dual disc clutch (most dual discs are 6-8", Mcleod are 10" or so) so the friction surface is very far away and has tons of leverage. Guess what, now the weak point is the poor little 1.5" steel input shaft. And the weak point of the input shaft is the splines so they strip.

 

thanks for the pic cory that is what mine looks like only worse.on monday im going to get everything laid out and take some pics.

anyone ever replaced an input shaft. how involved is it on the T56

 

Cory and Payam both are missing the point, yes the further away the more force is being applied on the splines its like leverage no one is saying thats not the case, what I'm saying it that will not cause the input shaft splines to go first I would think it would cause the disk splines to strip if anything.

Also, I still think two splines is better then one, I don't see your theory of 3cm of grip area being better then 6cm with two disks, on the picture you even show prooves that you have two disks acting on the input shaft not one, unless a one disk system somehow grips more of the shaft IE. Thicker splines it would not be better.

Payam, how does flywheel weight not matter? clutch engages and its applying it's weight when it's spinning on the shaft.