You never know bleeding might help.

So are the two disks combined actually lighter than the single? It doesnt seem likely? No one has shifting problems like this with twin disk clutches?

There have been some people reporting that this problem can be corrected by using different tranny fluids. The theory is that some lubricants are too slipperey so the syncros don't grab/work as well as they should. I am running Red line 75/90 right now and I have some royal purple that I plan to try next. There was a noticable improvement with the redline, especially cold and normal shifting.

I am heading out of town for a few days, I will try to check your progress on the road.

Regards,


Eric

 

Actually, I cannot believe that you just mentioned the tranny fluid being TOO good as I had the EXACT same thought and I just figured that it was too far out there to be reasonable. I even wondered if there might be a way to test the tension afforded by the syncro's with the normal tranny fluid compared to a good fluid like MT-90 or GM syncromesh. I have to wonder if you are right in that assesment, maybe the fluid is TOO slick so that there is just not enough friction. I personally would much rather have notchy shifting then to not be able to shift at all.

 

If anything it sounds that there is too much synchro resistance to get a quick shift done. Generally, it is easier to shift quickly if there are no synchros left in a transmission even if you might get a slight grind if your timing is a bit off. But why there is more resistance with a different clutch is a really interesting question. It sounds like the release is slower or that it may have to do with thickness and/or weight of driven disk or possibly pressure plate deforming because of too heavy a spring load. And this may somehow be interacting with the stock clutch operating mechanism.

 

All good points! sounds like we all have some research/testing to do. Besides being embarassing and annoying those shifting problems always happen at the most inapropriate times, racing.

 

Damn straight, it always happens when you really do not need it to. I always feel like just ripping the damn shifter back doing the 1-2 shift when it sticks, but I know that if I have to force it then something isn't right. I have tried foot to the floor smooth, slow shifting, foot to the floor fast, pulling it out of gear as the pedal goes down so that it is down going into the next gear, all sorts of diffent techniques. What really gets me is that I have problems 80% of the time, but 20% of the time it will just slot right in for no apparent reason. Its like gambling, you just don't know what you are going to get, and I hate gambling on a good shift when you are getting after it.

And Eric, I do not know that the twin disks weigh a lot less, but the rotational inertia is not so far out on the disk itself and I would think that the actual weight of the clutch disks them selves between a stock style single disk and a built twin would actually be pretty close anyway. From what I have seen it looks like the twin disk does not have as large of a diameter, so maybe the twin disks are just easier to spin down?

 

I just had to post on this topic that Dirk from ACT, otherwise known as ACTman just gave me a call to try and resolve some of the shifting issue's that I am having. He just spent 40 minutes on the phone with me going over the problems and possible causes. All I can say is that this type of customer service will keep me coming back as he is more then willing to work with me to figure out what is going on. He gave me several avenues to look at in order to resolve the problem and was just generally very nice and helpful. I just wanted to say thanks to Dirk and to let others know that these guys seriously do stand behind their products, and he is EXTREMELY knoledgable in his field of expertise. I will post later on what is found.

 

I'll second that...Dirk is definitely a stand up individual...extremely helpful and quick to get responses...he definitely provides the type of service that many companies lack...

oh yeah...please keep us updated...thanks...

 

I just wanted to post on this subject because with ACTman's help I was able to resolve the shifting issue's that I was having with the ACT clutch. He had suggested two things to try in order to get rid of the sticking clutch. Number one was to try removing the underdrive pulley and put the stock dampner back on and some high powered DSM's have had torsional vibration problem when the dampning was removed. The second suggestion was just to adjust the clutch rod out so that as soon as I pushed on the clutch pedal the takeup bagan immediatly. I was very suprised to find that I could adjust the clutch rod so that I lost about an inch of free-play before the take up started. I had not adjusted this when I put the clutch in as it had worked where it was with the stock clutch so I assumed that it would be cool where it was with the new clutch. Bad assumption. When I took the car out for a drive after I did these things I could rip of shifts just as fast as my hand could move, no sticking, no drag at all. This coupled with the GM syncromesh fluid and the tranny is smooth as silk and lightning fast as well. What I do not know right now is if taking the underdrive pulley off helped with the problem or not. I do know that there is a perceptable difference with it off. If I get a chance I will put it back on tomorrow and see what the difference is.

 

Hey Joey!

Thanks for the update, valueable piece of info! Sounds like it would have been a lot easier to try the pedal adjustment first .

I am betting that the pedal adjustment is what really fixed your problem, considering that many people with the stock pulley have also reported this problem.
Mine is not nearly as bad as yours was, but I have noticed this high RPM/speed shifting problem ever since the car was bone stock. From what I can tell it does not seem to be related to any particular clutch either, although the heavier pressure plate may have exagerated the problem?

I am definiately going with ACT when/if the stock clutch ever let's go, more than 24k and over 300WHP and it just won't give up! Did you resurface or replace your fly wheel?

Hey, maybe your making more HP now with the stock pulley!

Thanks again,

Eric

 

Yea, I resurfaced the stock flywheel when I did the clutch. It really was not very bad, but it is best to do it when everything is apart anyway. I want to put the UR pulley back on tomorrow, but I got sidetracked after torquing the lug nuts and like a dumbass left the key to the locking lug nut on the lug nut when I left the house. That sucker is loooong gone. I have to go up to Don Herring tomorrow and see about getting another key. There goes a sensless $30-$40. And I bet that they have to order it.

 

great news joey...glad it all worked out for you...I'll definitely have to remember this when I get mine installed...

just for clarification though, when you adjust the clutch rod, you are turning the rod so that the rod moves toward the master cylinder correct?...basically bringing the clutch pedal slightly closer to the floor?

 

You are actually moving the actual engagment point out so that the clutch starts to release a bit earlier. The same clamping forces apply, but the clutch moves the slave cylinder further assuring a positive release of the pressure plate from the clutch disk. This way there is no drag on the disk during shifts which allows the synco's to do their job without having to combat drag on the input shaft side.