Mine is a Spec 3+ single. I ve driven it about 100 miles now and it seems to be useable- I wish it released higher but im getting used to it. What im not used to yet is the aluminum flywheel... You have to rev it alot higher to get it rolling from a dead stop now... I wonder if it ll rev up alot faster? I hope its worth it.

 

I wonder if an adjustable master would alleviate this issue?

 

k called spec again today.... bunch of contradictory information
Spec says 100% to use the shim
Tick just installed one on my buddies SS trim twin....no shim required and they measured
England green...they said they only installed 1 but it didnt need one but that was with a different bellhousing
ECS....100% no shim required on C5s
so I leave you at that
I have to wonder if the shim is a bandaid for the crappy stock master not putting enough fluid in the slave to disengage the clutch all the way

 

Sounds like with all of Kurt's mods lately, Tick adjustable sounds on the way!

 

Sounds like exactly that! Im really considering it myself. Its the only choice -imo- if i want to bang the gears any more aggressively than "granny shifting". Also- Thanks Kurt, for the info!

 

Spec says install shim with twin disc.

Most reputable tuners don't install shim.

Hmmm I guess the best thing to do is go with what the manufacture recommends. Anyone have the clutch installed with shim and can you provide us with any feedback?

 

Well, I got the car buttoned up today and the clutch so far feels great! It has almost stock-like pedal pressure and grabs on demand and no chatter. We used the shim per Specs over the phone instructions. We put in all new slave and master. We also put in a set of Pfadt shocks and Pfadt comp sways and hypercoil composite leaf springs. All to be tested next week at Spring Mountain for Corvette Track days.

 

Glad it worked out for you on the first install.

Did you measure or did you just put the shim in and go?

I plan on measuring and using the shim, if needed.

 

I spoke with Tick today - they are having a sale/group purchase for the f-body version only @ ls1tech - so no rush as the vette version is regular price. They told me that the tick master for the vette can be installed at a later date without removing the torque tube, etc. So, I am going to install the spec twin and do the drill mod to increase the flow from the stock master cylinder. If needed, I will buy and install the tick adjustable master cylinder at a later time.

 

Kurt

Can you take some pictures of how you do the measuerments to see if the shim is needed?? If you take measurements, what were they?

Like I stated previously,,,I ONLY want to do this clutch install ONCE!

Bill

In Sunny Guam

 

I went ahead per Specs over the phone directions and used the shim. My installer looked at it and thought the shim wasn't necessary, but Spec said "yes" and if something goes wrong I'll be contacting Spec.

I thought the same thing. I went with a Napa master and if it fails I'll be calling Tick too!

 

Getting ready to install my spec twin with shim. What should I torque the pressure plate bolts to? With stock GM flywheel bolts is 75 ft-lbs okay?

Thanks

 

I called Jeremy at spec for tq values

Bill sorry just caught this thread...I didnt take pics of measuring

I put a piece of flat stock on a properly tq'ed clutch...has to be fully installed
then i took a caliper used the depth side of it with another piece of flat stock laid on the bellhousing to tq tube surface. Took the measurement...try and get a few for a accurate measurement...then depending on how you took this measurement add and subract the values of the flat stock (add the flatstock thickness that i had on the clutch fingers and subract the flatstock thickness on the mounthing surface of the tq tube and bellhousing

write down that measurement A

next is to install your slave without a shim have someone hold the slave completely depressed. Take the measurement from the throwoutbearing surface to the tq tube surface....add subract the values for however you got this measurement

write down this measurement B

the value of A should be (varies from who you talk to) 1/16-1/8"(Ticks recommendation) larger than the value of B....or Slowhawks recommendation 1/8 to 1/4 difference...his reasoning for the larger value was as the clutch breaks in/wears the fingers will come out thus making this distance smaller

I measured and came up with 3/16"

I called Tick they said if i was to use the stock master they would shim it (shim was a hair over .100 thick) if I was to use the Tick master they would not shim it.

So my thinking...I'd rather have to install a master for disengagement issues (dont have them but IF) than to take it apart and pull a shim out due to preloading the clutch issues or as the clutch wears this distance shrinks and could possibly preload the clutch causing premature wear due to clutch not fully engaging
Say if if one had a measurement of 1/8 without the shim (.125) and used the shim per specs instructions (shim was approx .108 that would only leave .017 gap for breakin/wear....so I think I did right
Hope all that makes sense, I have about 500 miles on my PT trim now...FINALLY most of my chatter is gone...all I have spoke to with the SS trim say it is like butter, no chatter even right after install/for breakin process
Pedal pressure is light and this baby grabs

 

Hey guys...I just found this thread and wanted to provide some info from the "horse's mouth" so there was no further confusion of this point. Our initial Twin didn't require the use of the shim as a result of our use of a taller diaphragm. Nearly a year and a half ago we switched to a shorter diaphragm and as a result require the use of the shim with our Super-Twin on LS based applications. I apologize for any confusion regarding this. Please let me know if you all have any further questions. Thanks as always!

 

I will be pulling my ENTIRE drive train soon to repair my BROKEN STARTER boss on the engine and will be installing my SPEC Duel Disk during that repair.

SO,,,,if I conduct NAT'S A$$ measurements (thanks Kurt) and it indicates that I DO NOT need a shim, what would be your recommendations on shim installation??????

If the measurements call for a shim,, its getting one. I also have a TICK Master to install.

Please let me know what you think about the measurement dilemma.

BC

 

That is exactly the point I was going to make. There are other ways to extend throw-out bearing travel (via pushing more fluid with the Titlon/Tick adjustable high volume master cylinder).

 

I cam across this thread after googling spec clutch shim. I just got off the phone with them. They could not give a definitive answer on the shim issue to me either. It is too much damn work swapping these clutches to do it twice. I'll never bother with a spec product.