Blue by U

I just finished a triple disc mantic install over winter which led to having to get an adjustable master cylinder. I finished install on master and clutch engagement is better! I want to get a little more adjustment, but when i do, the car wont start which i am pretty sure is due to clutch pedal position sensor. Anyone else had this problem?? Remedy?

car is a 2008 zo6, ive read that 2009 and up need a clutch relearn done by dealer, but not on a 2008...

Dano523

Lost on this, since with the correct spacing/shimming on the slave cylinder and clutch installed correctly, should have had about .125" free lash between the TB compressed all the way back against the slave spring, and the fingers of the pressure plate to start with.
https://www.corvetteforum.com/forums...uestion-2.html

Hence with the clutch and slave installed correctly,you do have the .125" free lash to begin with, OEM master cylinder works fine.


As for tick master cylinder, after the clutch is installed correctly with the correct free lash, then the tick (tilton) cylinder shaft is adjusted so the larger ID cylinder (which will push more fluid than an OEM unit for the same amount of pedal travel) is adjusted so the slave is not over compressing the pressure plate fingers isntead. Hence with the pedal stud point off set mounted, should have about 3/4"~1" of free play at the top of the pedal before it starts building up pressure isntead.

With all correctly installed and adjusted, then clutch pedal should be able to go the floor (without over compressing the pressure plates), to active/depress the bottom clutch pedal switch to allow the car to start.

The top of clutch pedal switch is used for the cruse control, to kick the system out as you depress the clutch pedal.


So if I had to guess, you did not install the clutch assembly correctly to begin with on the flywheel and now sitting proud, did not check the free lash of the TB to pressure plate fingers to see if the slave needed to be shimmed, or shortened (made worse by the clutch assembly sitting proud of the flywheel as well), and really don't have a clue to install (off set rod stud on pedal)/ final adjust the Tick master cylinder so it not over compressing the pressure plate fingers; when the rest is installed correctly as well.

http://www.tickperformance.com/conte...structions.pdf

As for a Clutch pedal switch relearn (CPP), only if the switch has been replaced, or you replaced the ECM/BCM.

Blue by U

mantic clutch does not have shims, and is installed correctly. Second one we have done, first being a twin, and now the triple that should the power better. I have dealt directly with Geoff Gerko at Mantic, and he said this is a common occurrence. The adjustable master is a hawks motorsport which is a tilton like ticks. This one does not relocate the pin on pedal like the tick does, which could be part of the reason.

Dano523

Tliton master cylinder has a much wider ID on the plunger body channel and it's going to move a lot more fluid that the oem master with the same stroke distance.

So even with the pedal stud for the cylinder rod moved up on the pedal to decrease the stroke amount, you still have to adjust some of the initial beginning pressure stroke out of the cylinder, so the cylinder is not over stroking the pressure plate fingers.

As for the need of the tilton unit, again, if your free lash between the TB and the pressure plate fingers is .125", the stock OEM master cylinder will work fine. Hence the slave spring is going to keep the TB gently adjusted to just ride the clutch finger (has the needed free lash as the clutch wears and decreases the gap so you don't run into problems instead) and will work with a tipple clutch as well.

As for back at the OEM slave, if the free lash gap is to large, then the back of the slave is shimmed to move it forward on the torque tube as it being bolted in place to reduce the amount of free lash. Tick sells slave shims that are different thickness, or you can produce a single shim of the needed thickness isntead.

Note my base line for free lash is .125", but this can be increase to .145" if needed; since the Oem slave will still have this amount of throw without problems. Less that .125" and you can run into problem as the clutch wears, and ending up with Zero free lash and the TB not releasing all the pressure off the pressure plate fingers instead.

If the problem is the other way, with the free lash too short instead, then the ZR1 slave cylinder is shorter than the Z06 slave cylinder (Zo6 slave is the same for the LS2,LS3 as well), and should be short enough to solve the problems (shimmed out as needed), .

Hence the last thing I would do is install a slave without the outer spring to take up the free lash slack as needed/to allow the clutch to self adjust cleanly, since this is going to end up with loads of TB chatter instead. Hence Tilton C6 slave cylinder in a street car.

Also, the metal TB race support, to replace the OEM plastic race support that loves to melt, is pretty much mandatory from the start on the OEM slaves.


As for the Tilton aluminum body master cylinder, prefer it over the oem plastic unit since its re-build able on the cheap/Id cylinder walls last a lot longer than the OEM plastic walls, but the glitch has been the ID of the plunger cylinder larger than the OEM unit, and pushing too much fluid per stroke instead; which has to be adjusted out, and ending up with too much deep pedal at the top of pedal stroke.



If Clinton offered a master cylinder that had the same fluid movement of the OEM per stoke distances, then life would be perfect instead.

So if your sure that the clutch is assembled and installed correctly on the flywheel, you have a .125~.145" free lash between the TB and the pressure plate fingers with the slave spring compressed all the way in once the torque tube was installed by using the needed OEM slave and shims if needed), then the problem your running into is the master not being adjusted correctly to allow the pedal to go to the floor, without over compress the pressure plate fingers instead.

As said, with the master rods mount point moved up on the pedal in the tick method install, you end up with about 3/4"-1" of intial free travel on the top of the pedal stroke. Using the OEM rod mounting point on the pedal isntead, bank that you have to about double that amount for intial free play to get the master adjusted correctly isntead, (so the pedal can go to the floor to press the bottom CPP switch in, and still not bottom out/over compress the pressure plate fingers via the TB instead.

Really to adjust the master cylinder rod, you want the clutch to just do a clean release at the bottom of stroke so you shift through the gears cleanly without trans bind with the pedal all the way down, then give the rod an extra turn outwards off the nut/shaft to make it slightly longer, and tighten the lock nut down.

If you cant get the pedal all the way down to start with, then the adjustment rod has been spun out to far to start with. Hence start too short, then slowly adjust it out just enough get the trans to shift cleanly with the pedal to the floor/motor running, than add in one more spin of the adjuster longer, lock the nut and call is the adjustment completed.

Blue by U

thanks for all the info dano523. I appreciate the help. I guess i should have given more information on my original problem. After installing the triple, i had a problem with getting the transmission into first and reverse. It would go, but not as smoothly as it did with twin. The new adjustable master has fixed the problem with the added hydraulic flow, with it being adjusted to same rod length/pedal height, as the stock master. I was just trying to adjust where pedal starts to engage off the floor. It is almost on immediate movement of pedal. I have about an inch or slightly more of free play at top of pedal before pressure while pushing in from top.

i appreciate you taking the time to do the in depth responses. Thanks.

Dano523

No worries, but would still do the Tick clutch pedal cylinder stud relocation mod, since this will will decrease the stroke of the master cylinder over all on the total pedal stroke, to allow less top dead stoke at the initial start pressure stroke of the pedal instead.

Hence without the stud relocation and you having only 1" of top dead stroke that is not starting to build up pressure of the initial clutch pedal push, still think that you may still be over compressing the clutch pressure plate fingers as the bottom of pedal stroke when the CPP sensor is pressed in.

Without the pedal stud relocation, you should have a good 1-1/2"~2" dead top of pedal stroke if the TB to pressure plate fingers where set at .125. So on that note, give the clutch a chance to mate in/everything square up, and go back and double check the needed amount of dead top of pedal stroke needed afterwards.

Trust me, the last thing you want is the pressure plate fingers bottom out and you over flexing them more past their real stop inner points, since this will end up with a broken/collapsed pressure plate finger quickly instead.

Jfryjfry