CYLT4

I Am In The Process Of Converting Over From A Stock Dual Mass Clutch Assembly To An Aluminum Fidanza Flywheel And Stage 2 Clutch From Carolina Clutch. The Problem I Am Experiencing Is Once It Was All Put Back Together The Clutch Will Not Disengage From The Flywhhel Enough So That The Gears In The Transmission Can Be Changed. With The Engine Off The Gears Will Slide Right Into Place But If The Car Is Started The Moment You Try To Engage In Any Gear The Car Starts To Move Even With The Clutch Pedal Fully Depressed.the Problem All Started When The Original Clutch Assembly Clutch Fork Ball Stud Decided To Back Out About Three Threads Therefore Causing The Clutch Fork To Hit The Pressure Plate When The Clutch Was Depressed. Could The Clutch Fork Be Slightly Bent? Has Anyone Else Experienced This During The Conversion. Please Help I Am Ready To Get The Vet On The Road Again.

LD85

Is the single mass thicker than the dual mass?

If not then the fork "could" be bent, but I doubt it, that is really thick steel.

Or the pivot stud is not seated against the bell housing.

Or your clutch slave is not travelling far enough

How thick is your bellhousing from the tranny mount to the engine block mount surface,, 5.875 or 6.125"?

I ran into this problem too on my 4+3 to ZF swapand found out that there are two different thickeness' of ZF bell housings.

CYLT4

According To Tom At Carolina Clutch This Was A Straight Bolt In Conversion. No Need To Machine The New Flywheel To A Certain Thickness Or Any Modification To Existing Equipment. The Ball Stud Is Seated In The Bellhousing And It Had A Few Drops Of Loctite Applied To Keep It From Backing Out Again. I Oredered A New Clutch Fork But I Agree It Would Be Hard To Damage It.

byte_me

How old is the slave cylinder? and or did you have to remove any of them (master or slave and\or the line) thinking maybe need to bleed the system...

If not- the FW may be thicker then original....when doing my ZF swap into a 4+3 84 vette- I reused my 4+3 FW that was much thinner then the Dual Mass unit...therefore I had to use a longer pivot ball stud to make up the distance...is it a new pivot ball or the same one? can't imagine bending the fork...but it is possible I suppose...

Good Luck!

LD85

I agree this should be a straight bolt on! It NEVER happens for me this way,, but I hear that it does work that way for some

If the clutch disc is thicker than stock that can be an issue some times.

But, first find out how much the fork is hitting the Pressure Plate, you could grind a small mount from the back of the fork in a 1.5 inch swath were it touches the PP. I tried this for added clearance and ,,,no,,, I am not concerned about my forck bending.

jburnett

If you're still running the stock ZF dual mass pivot stud then you've found your problem...
-Jeb

LD85

jeb, is this because of a dimensional difference in the flwyheel thickenss?

chriswtx

Ttt

CYLT4

I Am Still Using The Stock Ball Stud But Where Do I Get The Right One From?i Was Told I Didnt Need To Modify Any Original Equipment. The Slave Cylinder Was Bleed Even Though The Hydraulics Were Never Opened Up.

Stingray1970

In converting my 91 to a single mass, I used an F body flywheel (had .090 machined off) F body disc and a Corvette p/plate. Works fine a bit noisy in neutral. However the BMW 15-60 oil did make it a little quieter. Be sure there isn't air in the clutch hydraulic system. I would think the problem is mechanical not fitment.

LD85

Your local Chevy dealer can get you one, just have them look up the part number for the ZR1 model and they can usually get you one in a day.

CYLT4

TOM AT CAROLINA CLUTCH WARNED THAT MACHINING A F BODY FLYWHEEL( .090 OFF) LOWERS THE THICKNESS BELOW THE RECOMMENDED MINIMUM AND HE HAS SEEN THE FLYWHEELS CRACK AND BREAK. BUT HAS ANYONE ELSE HAD TO USE THE ZR BALL STUD TO MAKE THE CONVERSION WORK? I AM TIRED OF SPENDING MONEY ON PARTS HOPING TO GET A FIX. IT IS BECOMING A MONEY PIT.

LD85

Another method is to take .050 to .075" off the crank mounting hub on the backside of the FW, this works well too as long as you dont take too much off.

I would imagine that there is a difernece in the crank hub offset and maybe the overall thickness that combines to make the stack up too close to the tranny.

Just get the ZF ball stud if thats all there is too it. That way you dont have to pull the FW, PP and clutch back off.

Good luck! I feel your pain!, Been there done this x4

LD85

ZR1 Pivot Stud GM # 10227809

Chevy Guy

Id look at the slave cylinder first. Sounds like a hydraulic problem to me.

MYCoupe

I believe this to be the problem. A while back someone had posted pictures of the two (LT1 and ZR-1) and there was a slight difference. Only really noticeable when you had them side by side.

CYLT4

I Do Not Think It Is A Hydraulic Problem Since The Stock Clutch Was Working Prior To Disassembly. The Only Problem Was The Ball Stud Had Backed Out About Three Threads And When The Clutch Pedal Was Pushed All Yhe Way Down The Clutch Fork Would Grind Against The Pressure Plate. I Will Try The Zr Ball Stud Route To See If That Is A Fix. I Wish Someone That Has Done A Straight Dual Mass To Fidanza Aluminum Flywheel And Stage 2 Clutch From Carolina Clutch Could Step In And Say This Is Definetly What You Need To Do.

byte_me

Here is what I used the ZR1 pivot ball stud to do:

I reused my 84 4+3 FW that was thinner then a Dual Mass- the longer neck on the stud gave me the distance needed to engage\disengage the clutch...the stud was modified (bought it from a forum member) the back part that screwed into the bellhousing was machined down....I used a stock LT1\4 clutch and pressure plate as well as the TO bearing. When all was said and done- the clutch release was a little higher then before (pedal wise) but nonetheless, it worked...if your new FW is thinner then the stock one...the longer pivot ball stud will give you the distance...

Hope this helps...

jburnett

That is correct... Sorry I've been out of town for a few days and wasn't able to get back to this thread. The thinnner single mass flywheel requires the different pivot stud for proper disengagement. I did this conversion back in '95 on my car. At the time TPIS had come out with a kit and they sold the pressure plate, disc, and the pivot stud (all RAM clutch pieces and the ZR1 stud); I bought a 88 4+3 flywheel as well. Straight up conversion. Easy as pie.
-Jeb

CYLT4

talked with tom at carolina clutch today and he assured me that their kit is a straight bolt in. after some discusion with my mechanic and a few measurements later it was determined that my specific car had some tight tolerances and the first clutch disk was a few thousands of an inch too thick. without hesitation tom measured a different kevlar disk and found it was slightly thinner than the first disk so he sent it to the shop no questions asked. it will be installed tomorrow so hopefully this will cure the disengagement problem and allow me to ride. i will post an update tomorrow. i never realized the tight tolerances of the clutch and flywheel combos until now. all it takes is about .050 inches to cause trouble. i am like a kid waiting on christmas to get the vet on the road to see if i can feel any difference from the exotic muscle long tubes and fidanza flywheel. it seems it should rev quicker with the free flowing exhaust and lighter flywheel.