So I'm hoping 3rd time's the charm for my '92 vert. I think the factory dual mass clutch got 100k or so on it, and then i went to the single mass steel flywheel with spec performance clutch. First i had a shop install the clutch which i got from summit racing. Worked for a while before burning out. Since the clutch was warranteed- I wound up having a shop do the replacement- then it burned out again. Giving up one the single mass, i found a deal on a factory clutch/trans combo and installed it myself. Unfortunately, as it was my first attempt at a clutch replacement, i apparently didn't seat the throwout bearing properly, and destroyed that when the fork partially came off. The good news is that i had all the spare parts available to do the job yet again.

This time i went back to the spec clutch since money's tight and its still under warranty. This time i'll be extra careful with that bearing- any tips on getting that thing off/out? its always a huge pain. As is the aluminum channel surrounding the driveshaft.... anyway, to the big question: What could be causing all this clutch burning? This is a daily driver and not a race car. I don't feel any dramatic vibrations like somethings off balance- the clutches just seem to wear super fast! Am i screwed if i don't have the factory dual mass for balance reference? I've heard rumors...
Anyway, check out the wear in these pics- I'm sure the fact that its worn significantly more at the edges means something to some of the experts out there! thanks for any help in any regard!
-kevin
what components are balanced to a particular rotation?

See pics here:
http://www.kevin-design.com/combined.jpg

 

From my experience many years ago. I think your linkage isn't fully releasing. You don't have to pull the transmission up with the bolts do you? From what you've said you need to investigate that throw-out situation.


JS

 

Hi Kevin,
I,too, have a 92 vert. If you want to reinstall the dual mass flywheel, it would be nice to have the old DM to see where the weights were positioned. However, there is a set of procedures for placing those weights.

Next, did you have any problems shifting with the clutches you are burning out? If the clutch is not disengaging completely, the ZF tranny doesn't shift easily. Also, some single mass flywheels need to be ground down a bit for proper workings of the clutch engaging/disengaging. Maybe your mechanic didn't know that. Did you notice any slippage just after you had those clutches put in? Slippage means heat.

 

So now that i've spent a weekend under the car (ignoring my doc's advice re: recent stitches) struggling to get the clutch, flywheel, and pressure plate removed, then shipped back to spec for their evaluation and replacement-- keep in mind that i had to do this myself since garages wouldn't take my car and leave it in that state while spec gets parts shipped back.... anyways, so after they invited me to return the clutch and provided an RMA, now the line I'm getting is that its out of warranty despite the fact that it was replaced >1yr ago under warranty. Their tech says its normal wear. So for the record it sounds like we all need to adjust our expectations of spec clutches to be 1 year or 6k miles.
Lame.

In response to your helpful replies in the thread:
Strick- (you live at Lake Wylie? cool!) do you know the procedure you mentioned for placing the weights? I dont have the original flywheel anymore. I didn't really have any dramatic shifting trouble with the trans, but I was getting a sense that the synchros might be a little off. Also the ever-present forced 1-3 shift (anyone know how to remove this 'feature'?) for economy. I didn't notice slippage when they first put it in but did notice a burning clutch smell.

Jsinga: Please describe what you mean by 'pull the transmission up with the bolts' I did have the jack around the transmission a lot to get those long through bolts into the aluminum channel around the driveshaft. Another serious pain (getting the holes to line up- also getting nuts on the opposite side)

All:
Still looking for tips on getting that fork on/off. Its a real pain. Why is that 12mm allen head threaded in the center?
Is it normal to have a worn outer edge of the clutch disc and not so much at the center? Doesn't appear normal to me.

As always- thanks for any help!
-kevin

 

I don't envy you doing this on jack stands , did our 94 via a lift and a trany-jack with my brother, and it was still challenging, especially given the weight of the ZF6 trany (albeit was my first 'american' clutch job).

Others I'm sure are more experienced at this than I, but I can offer these thoughts:

1. Review ZFDOC.COM, lots of good info.

2. To my untrained eye, it looks like your not getting full disengagement or engagement. Are your clutch hydraulics working up to par or is the actuator perhaps wrong and has too long of a nose shaft? If they have over 50k on them, consider replacing both master and actuator (slave), and if over 100k on the hose, replace it too (albeit expensive as it has stainless steel mesh cover). Also consider NAPA for these parts, they have a lifetime warrantee on theirs (albeit I used GM's, I did have the actuator fail within 6 months, maybe because of the incorrect bleeding approach of pumping the pedal without actuator installed, which allowed the piston/rod to push into non-machined and slightly rusty areas of the bore -- saw the slight rust when the nose rubber cone also popped-out).

3. Do you have the Factory Service Manual (aka Helm)? If not, suggest getting it. It explains the trick for getting the fork off (says to align the fork fingers on the flats -- in between the 4 'ears' -- of the release bearing and then pull the fork backwards (push forward where actuator contacts it). It worked for me (albeit on a lift not underneath like you are).

3. The 12 mm allen head on the back of the fork pivot is REQUIRED. It locks the pivot ball and prevents the pivot ball from backing-out (and it will, it did on ours just before I was doing the clutch -- thanks to some previous 'mechanic' not replacing it -- and thanks to this Forum for understanding what it was before hand). By the way, you shouldn't need to remove this to disengage the fork from the release bearing, but if you did, be sure to put lock-tite back on both the pivot ball and the locking nut and torque both to specs (pivot=33 ft/lb and locking=11 ft/lb for our 94 'LT1' per the FSM/Helm).

4. Regarding getting around the forced 1-4 (aka 1-3) shift, there is a CAGS bypass plug available at Ecklers which I installed and works great. The dash still shows the light which we ignore, but no DTC errors as promised, here's the link: http://www.ecklers.com/product.asp?p...A7K4URWN8V9H1E

5. I replaced the DM (along with everything else including rear-main, pilot, etc) and the car shifts fabulous, even with 97k, but it was likely the 2nd or 3rd DM (thanks to previous owner's 'mechanics' mis-diagnosing the trany seal leak as a rear-main). Since I didn't have the original DM, didn't know if/where to put in weights, so went without. There is a slight vibration at about 1500 rpm, though.

SO STRICK, if there is a procedure I'd also be curious, just in case I ever feel like taking it apart and trying it (not likely, but you never know).

Hope this helps.

 

As far as showing you guys the GM procedures for balancing the dual mass, I don't know how to do it. I tried scanning the document, but can't figure out how to post it on the forum. When my son comes home some time this month, I'll get him to figure it out. Anyway, you have to remove the inspection panel on the bell housing, and be able to rotate the flywheel and follow the positioning of the weights which you drive into the holes on the outer edge of the flywheel. They give you 5 or 6 different positions of the weights and it's trial and error to find which positions work best.

 

I think if you do not have the data on where the balance points were, you should just have your flywheels neutral balanced. most vendors will indicate that their FW's are "GM" balanced, for what thats worth.

 

thanks for the help folks! please keep it coming! just a real quick post at the moment- about those pics in the original post: See how there are blushed out marks on the contact surfaces toward the inside of the components? In contrast to the undisturbed contact surface at the outside? This jives with the fact that the clutch itself is worn at the outer edge- but how is any of that possible? I dont get it.
More later- but thanks again!
-k

 

My factory 70k clutch I took out when rebuilding my motor was worn in a similar manner. I don't know for sure that is normal, but mine was that way and had 70k on it. Did you have the camaro flywheel put in or some aftermarket single mass flywheel? I used the camaro one and had to turn .080 off of it. Good luck in solving your problem.