What have you done there? I can't tell from the pics, how you secured the clutch-side mass to the lathe?

 

And... what did you datum for flatness? Did you have to tram it in?
Looks like a 4-jaw ID clamped but I would also like to know.

 

You might be looking at a 98-02 which used a different setup. I know the spline count is the same for the 93-97. I’m running it with a Fidanza.

 

Be interesting to review. But there are always the claims of “made in the USA” on a repackaged or rebranded setup.

 

I just posted that the throwout bearing in the spec stage 3+ kit i bought in 2012, wasnt the crappy made in china one that i got in with the stage 3+ kit i got in 2006

it appeared to be high quality and custom made. Read my post it was very different

that said, i had an NOS blue tag throwout bearing and i found a blue tag guide tube.

so if my memory is right, i used that and packaged away the custom one SPEC had included with the kit.

it will take me some work to find it, but if i do ill post a picture

 

Right, both the ZF6 Corvettes and the T56 F-bodies use a 26-spline input. I am 100% sure they are interchangeable.

That's interesting. I didn't snap to the time sequence of those when I first read your post - I read it as "2002" instead of "2012." My mistake. The one I got in 2016 was most definitely not a nice custom billet piece...unfortunately. I'd hang on to that TOB if I were you!

 

r1 have known bill since then when I had a clutch problem and he helped me out as well as Greg . We together have totally rebuilt my car over the years . It’s just clocked over 250 k miles . The reason I want everyone to call him is I know how articulate bill is and didn’t want to say the wrong thing about what he has found out . He and Greg have done over 500 clutch installs over the years and the last 4 years the quality of clutches that have been for sale . He and Greg had to redo quite a few not due to incorrect install but due to the parts that are being sold to everyone has done down hill a bunch clutch discs being built at the wrong thickness and basically warped from the manufactuerrrs so sorry . We spun some of these discs when I was there for 8 days on his lathe and litterly watch them wobble as much as 1/2 in now to the pressure plate they are being built from the factory with unequal spring pressure so much do that brand new clutches can be so bad that they only grab 1/3 of the clutch disc so did any speed shifting or road race down shifting and listen to it slip a brand new clutch . I personally watched bill on the bench show me by putting a brand new pressure plate on a brand new flywheel and watch him take his hands and rock the pressure plate in and down shouldn’t they be flat against each other . He had spent a great deal of time figuring out how to fix these kits so that they will last as they should . I won’t try to explain how he figured out how to gix these problems so your clutch last as it should as he I was a engineer on the aerospace industry for years . And hehe they talk funny to me . I am sorry if I offended anyone here that was the farthest tho g from my mind . I just didn’t want someone to put all that work putting in a clutch just to have it fail way too soon and either hate their car or think they did something wrong . And maybe burning up there zf transmission because the clutch wasn’t operating right . I really do hope this helps ingeneral terms what I saw and what can happen due to bad manufacturing . Everyone have a great day and hope this helps

 

Oh I have know bill since 1998 when I first had a clutch problem I have had 2 zr1s over the years my 90 purchased from a car lot in Reno with 76k miles on it and a 1992 callaway supernatural 475 that I purchased in 2007 with 30 k miles and sold to Gary Guin in dec 2014 with 161 k miles . So that’s my c4 history

 

You used to have two 90 ZR-1's. A Black one and a Red one.

https://www.corvetteforum.com/forums...-for-sale.html

Forget about that one?



But this post sums everything up quite nicely.

https://www.corvetteforum.com/forums...post1565893361

 

He said he went to help @Cuisinart vette in that thread. Maybe he will contribute....



Has to be some other good threads. Why so many names, stories, and locations?

 

Thank you. This thread now has some clarity.

That is what I call..."Not a good forum contributor".

 

I made this mandrel that is the same mounting as the flange of the crankshaft. This was finish turned in the lathe that’s was used for flywheel machining so it ran perfectly true. Bolted flywheel to it as if installing on crank. In order to support the friction side of the flywheel, and to keep it from rotating in the hub, I used 3/8 set screws through the PP mounting holes to make contact with the main side of the flywheel. To make sure I didn’t distort the flywheel friction side, I laid the flywheel on a flat surface and placed dial indicators on the friction surface to make sure I didn’t over tighten the set screws and warp the friction surface.

 

I called the ZFDoc today. I am in the middle of a motor rebuild and clutch replacement on my 96. While waiting and waiting and waiting on my block work, long story, I want to have all of my clutch stuff ready to go when the motor is finally ready.

First off when I took the old clutch out the DM flywheel would rotate way far out of the allowable amount. So away it goes and in comes the new Fidanza flywheel. Then off it goes to get balanced to match the old junker.

Also found metal shavings in my bellhousing. Back of the clutch fork was rubbing on the edge pressure plate. ZFDoc explained this happens when the end of the fork that accepts slave cylinder bends a little bit. Hard to see it but that's what causes that interference. The middle area of that fork is plenty beefy and wont bend. Off to MelroseCorvette for a new fork, ballstud and locking nut. I am very glad he explained that to me. That was my main reason for calling. I didn't want to get it all together and find it still not clearing.

While waiting for other parts I installed the noise reduction kit on the front of the trans. I had to also buy a really nice pair of snap ring pliers to get that old spacer out. Those small ones they sell at the local parts store wont do the job. But hey, who doesn't love buying tools.

We talked some about the pressure plate. He said he can level them out, or actually he has his machinist do it because his lathe doesn't have 14" clearance. As Matt has done he totally explained what is going on and it makes sense. Next I send my PP to him for leveling. He did say the TB he has been receiving lately from Carolina Clutch have been more than acceptable. So I think I am good there. With all that being said I am going to be into this clutch for a pretty good amount of coin for a stage 2. At the same time it should be a good operating unit that I can count on to work properly.

As many of you have said he is a super nice guy and you can tell by how he talks about this stuff he really does love working on and more importantly understanding how it all works and how to optimize the system.

All in all it was a very informative 20 minutes. I am thankful for his time.

96 corvette build has now doubled the budget. But that always happens when you start adding in the old "while you're in there..." items.

 

That's really good news! That's where I'd source mine, then. Since there's no casting/mold involved in making these, there are probably multiple factories making them (unlike the pressure plates). Good to know at least one of them seems to be okay.

 

Maybe if we keep putting pressure on these clutch companies (har, har) they'll stop sourcing sub-par parts and this won't be as much of a problem anymore. That would be pretty fantastic.

 

Just had a NOS OEM dual mass flywheel apparently fail after 3k miles. The symptoms (noises) are loud and unmistakable. Car is a 92 w/ LT1 with 100k currently. Haven't disassembled it yet, figured I'd have to go single mass, etc. but this thread, by the time I got to the last page, really puts me into a quandary. Suggestions?

 

Wow, a DM flywheel fail in 3k miles. Are you sure the pressure plate isn’t what failed?

 

Well, wouldn't bet my life on it... but the noise, verified by several sets of professional ears with and w/o a stethoscope and the car running on the lift, is definitely from the bell and the sound is the irregular "tick" or metallic knock like metal ***** rattling around in there. The noise comes only at idle and only after the car has been driven a few miles to warm up. On shutdown there is a final staccato burst of ticks as the engine stops. My mechanic friend subscribes to a diagnostic service that reports several other identical sets of symptoms that were generated by a failed dm wheel. True, they all had at least 50k on them. I'm told that the two parts of the dm wheel do have steel ***** captured between them.

Before we did this more complete exam, I had emailed Bill Boudreau who suggested the noise was caused by short(s) in the plug wires, but we eliminated that and in any case, the engine doesn't have a miss. Haven't been able to get a further response from Bill, perhaps too busy. Can you think of anything else in there that would make that noise?

 

It does sound like the noises I'd expect from a bad DMF. Did you use a solid disk and not a sprung-hub disk? Because if you accidentally used a sprung disk, that could make interesting sounds.

 

Nope. The backstory is, I've owned my '92 for 16 years now, bought in '04 with 60k and shifting problems. This car came with one of a batch of bad slaves with internal leakage (IIRC) and therefore didn't fully release the clutch. The previous (original) owner just kept driving, eventually lunching 1st, 2nd, and R, gears and synchros. We did a rebuild on the trans and, of course, replaced the slave.

Ten years later I learned that the LuK dmf wheels were some years out of production, so I bought a complete new wheel/clutch setup from Jim Jandik to put on the shelf, as I tend to keep my rides forever. In 2015, with 97k on the car, I decided to put the new parts in to be able to say that any clutch issues were put to bed. 3k later this move has come back to bite me. I saved the old (worn but undamaged) parts and now I'm in a quandary as to which way to go.