Project clutch master cylinder/second gear grind

[IDEALG]

Originally Posted by 1977and2010

I don't know if anybody has mentioned it yet but what are they putting in the ZL1 or the 1LE. Didn't they do a whole bunch of hard testing with the ZL1. Wonder if its different and if it is will it bolt up?

I was wondering the same thing, but i dont have any part numbers for those yet. I was hoping the trans itself would have improvements on the ZL1

It wouldn't surprise me though if the ZL1 clutch master cylinder was the same as the SS.

[11SynergyGr&Bl]

Count me in. Im sick of it grinding or not going into gear from 1st to 2nd at 5k+ rpms. Suuuper disappinted in that aspect.

[BigCarrot]

Originally Posted by 1977and2010

I don't know if anybody has mentioned it yet but what are they putting in the ZL1 or the 1LE. Didn't they do a whole bunch of hard testing with the ZL1. Wonder if its different and if it is will it bolt up?

Very good point. I wonder if they improved that...

[calbert1999]

As long as I'm not the first one to test one I"m in. LOL

[IDEALG]

Originally Posted by calbert1999

As long as I'm not the first one to test one I"m in. LOL

My poor camaro got the first test. If i get the parts back from the anodizer tomorrow i will have a SS and a V6 ready for testing.

[VEESIKS]

The ZL1 uses a different 6060 than the SS. I believe it has different gear ratios. I would assume that they have all carbon synchros etc. Anyhow if you get a 6 cylinder version completed I am def interested in one!

[Blue70SS]

Put me on the interested list. Only thing I wonder, is if too much fluid is moved and results in over extended blown out slave. Definitely interested in anything that will help fix high rpm shifts.... 5500 and granny shifting for now. Not worth trashing an RPM tranny over. Subscribed....

[blumaro]

I've been following this thread for a while too. My 2012 SS exhibits the 1 - 2 grind at >6000 RPM. Very disappointing. I thought I bought a performance car. Anyway, I'm interested in seeing what they changed on the ZL1. According to this month's GMHTP review of the ZL1, they state that the trans gets different input and output shafts. I bet it's similar to the CTS-V. No mention of revised clutch hydraulics, but from a magazine publisher's perspective that's less glamorous than improved shafts, so who knows?

I'd like to applaud IDEALG for is efforts at trying to solve this problem. Thanks man! I'd also like to throw a couple things out there from an engineer's perspective. It seems from reading this thread that you're somehow increasing the master cylinder's volume in order to increase the slave's travel. What effect does this have at lower speeds? Is it causing the throw out bearing to over travel? Will this reduce the life of the pressure plate?

As the pressure plate's rate of acceleration and rotational speed increase, so does the force required to disengage the clutch. This would explain why the barely adequate hydraulics are having an issues with the 1 - 2 shift...the pressure plate acceleration is the greatest in first gear. Yet at lower engine speeds all is well, so that would indicate that the hydraulics provide enough travel to disengage the clutch. Following my logic, the question should be: why does the slave exhibit less travel at high rpm's, when the pressure plate is rapidly accelerating? I have a theory. Heat. It has been suggested that the instantaneous heat flux generated during rapid acceleration in first gear is causing the hydraulic fluid to boil and produce air bubbles, thus reducing the travel of the slave cylinder. I don't agree with that. There should not be any air in the hydraulic system. If there was, the problem would be evident at all engine speeds. Perhaps the real culprit is thermal expansion in the cheap plastics that these parts are made from. For that brief period of rapid heating in first gear, the housings are expanding just enough to allow fluid to leak past the master or slave or both sets of pistons. This would certainly reduce slave travel and also explain the stuck clutch pedal problem as well. I wonder if the solution could be as simple as some well placed heat shielding?

[IDEALG]

Originally Posted by blumaro

I've been following this thread for a while too. My 2012 SS exhibits the 1 - 2 grind at >6000 RPM. Very disappointing. I thought I bought a performance car. Anyway, I'm interested in seeing what they changed on the ZL1. According to this month's GMHTP review of the ZL1, they state that the trans gets different input and output shafts. I bet it's similar to the CTS-V. No mention of revised clutch hydraulics, but from a magazine publisher's perspective that's less glamorous than improved shafts, so who knows?

I'd like to applaud IDEALG for is efforts at trying to solve this problem. Thanks man! I'd also like to throw a couple things out there from an engineer's perspective. It seems from reading this thread that you're somehow increasing the master cylinder's volume in order to increase the slave's travel. What effect does this have at lower speeds? Is it causing the throw out bearing to over travel? Will this reduce the life of the pressure plate?

As the pressure plate's rate of acceleration and rotational speed increase, so does the force required to disengage the clutch. This would explain why the barely adequate hydraulics are having an issues with the 1 - 2 shift...the pressure plate acceleration is the greatest in first gear. Yet at lower engine speeds all is well, so that would indicate that the hydraulics provide enough travel to disengage the clutch. Following my logic, the question should be: why does the slave exhibit less travel at high rpm's, when the pressure plate is rapidly accelerating? I have a theory. Heat. It has been suggested that the instantaneous heat flux generated during rapid acceleration in first gear is causing the hydraulic fluid to boil and produce air bubbles, thus reducing the travel of the slave cylinder. I don't agree with that. There should not be any air in the hydraulic system. If there was, the problem would be evident at all engine speeds. Perhaps the real culprit is thermal expansion in the cheap plastics that these parts are made from. For that brief period of rapid heating in first gear, the housings are expanding just enough to allow fluid to leak past the master or slave or both sets of pistons. This would certainly reduce slave travel and also explain the stuck clutch pedal problem as well. I wonder if the solution could be as simple as some well placed heat shielding?

It doesn't affect low rpm shifting, you are very well on the right track and i'm with you about not believing in the air bubbles caused by heat. If that was the case then after you drove the car for awhile and got it hot it would be hard to shift into any gear at any rpm.
you have to understand that what i'm doing with these master cylinders is only increasing the slaves movement by a very small amount but a very small amount makes all the difference in the world on the pressure plates disengagement.

just Hang in there I got my NJ SS grinder waiting for me to get my cylinder done and we will test it. his car will be the perfect test subject he has a worked engine but stock clutch and an "aftermarket hurst shifter" <-- the worst shifter you could have on these grinder trannies. The extreme short throw of this shifter makes it easier to grind. If his doesnt grind after installing my master then im convinced it works.

[CyberPredator]

Originally Posted by blumaro

I've been following this thread for a while too. My 2012 SS exhibits the 1 - 2 grind at >6000 RPM. Very disappointing. I thought I bought a performance car. Anyway, I'm interested in seeing what they changed on the ZL1. According to this month's GMHTP review of the ZL1, they state that the trans gets different input and output shafts. I bet it's similar to the CTS-V. No mention of revised clutch hydraulics, but from a magazine publisher's perspective that's less glamorous than improved shafts, so who knows?

I'd like to applaud IDEALG for is efforts at trying to solve this problem. Thanks man! I'd also like to throw a couple things out there from an engineer's perspective. It seems from reading this thread that you're somehow increasing the master cylinder's volume in order to increase the slave's travel. What effect does this have at lower speeds? Is it causing the throw out bearing to over travel? Will this reduce the life of the pressure plate?

As the pressure plate's rate of acceleration and rotational speed increase, so does the force required to disengage the clutch. This would explain why the barely adequate hydraulics are having an issues with the 1 - 2 shift...the pressure plate acceleration is the greatest in first gear. Yet at lower engine speeds all is well, so that would indicate that the hydraulics provide enough travel to disengage the clutch. Following my logic, the question should be: why does the slave exhibit less travel at high rpm's, when the pressure plate is rapidly accelerating? I have a theory. Heat. It has been suggested that the instantaneous heat flux generated during rapid acceleration in first gear is causing the hydraulic fluid to boil and produce air bubbles, thus reducing the travel of the slave cylinder. I don't agree with that. There should not be any air in the hydraulic system. If there was, the problem would be evident at all engine speeds. Perhaps the real culprit is thermal expansion in the cheap plastics that these parts are made from. For that brief period of rapid heating in first gear, the housings are expanding just enough to allow fluid to leak past the master or slave or both sets of pistons. This would certainly reduce slave travel and also explain the stuck clutch pedal problem as well. I wonder if the solution could be as simple as some well placed heat shielding?

There was a company on the Corvette forum with a similar theory. I posted a link to it a while ago but most blew it off or didn't understand. I believe he was saying something about open dust ports on the bell housing to reduce air pressure and heat in the bell housing which lead to better high rpm shifts and no clutch sticking.

[IDEALG]

Originally Posted by CyberPredator

There was a company on the Corvette forum with a similar theory. I posted a link to it a while ago but most blew it off or didn't understand. I believe he was saying something about open dust ports on the bell housing to reduce air pressure and heat in the bell housing which lead to better high rpm shifts and no clutch sticking.

I understand your points here but a lot of us have low mileage cars that grind, there wasn't enough time for clutch dust and heat to cause trouble. my car has less then 5000 miles on it and its been grinding like this from day one.

[CyberPredator]

Well they weren't saying completely clutch dust (although that was part of it) the rest was air pressure built up in the bell housing from high speed rotation and a place for the air pressure to go. I'm no professional on the matter so I posted it up but people started talking about oranges

[blumaro]

Originally Posted by CyberPredator

There was a company on the Corvette forum with a similar theory. I posted a link to it a while ago but most blew it off or didn't understand. I believe he was saying something about open dust ports on the bell housing to reduce air pressure and heat in the bell housing which lead to better high rpm shifts and no clutch sticking.

I dug around and found the link you were referring to:

http://forums.corvetteforum.com/c6-t...ur-clutch.html

Good stuff. IDEALG is correct about this problem afflicting brand new cars. My car just broke 1500 miles. The first time I screamed it up to 6000 rpm it had 800 miles on it...grind. In horror, I pulled into the liquor store to grab some brews and let it cool down a bit. Pulled back onto the road and blasted up to 6000 and grind again. My head was about to explode (glad I grabbed some beers). I tried it one more time and made for-damn-sure that the clutch pedal was slammed onto the floor then I slowed down the 1 -2 shift just a bit and it went right in, no problem. My 4th gen never had this problem. It could take what ever I could dish out including bouncing it off the rev limiter, no-lift-shift style. The new car is very disappointing indeed.

That Vette article has me wondering if the Camaro has forward bell housing panels? Not so much for debris removal, but for added cooling. I haven't had my car long enough to have spent much time under it, so I just don't know. My other thought is, and perhaps IDEALG can chime in, how close is the clutch master cylinder to the exhaust manifold/system? There tends to be a huge amount of heat generated by the exhaust when driving the car hard. Perhaps a well placed heat shield could protect the master cylinder.

[CyberPredator]

I too was thinking that. My tranny since new did the 2nd gear grind but what I did notice is that it's smoother around 150° but when it gets to 180° it grinds every high rpm1-2 shifts. Which mine gets hot quick now because of Turbos. I was thinking Turbo bags and exhaust wrap.