High RPM lockout...help
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From: Baton Rouge, Louisiana
High RPM lockout...help
Okay, i officially hate my clutch. I replaced the stocker at around 65k miles with an Exedy stage 1... biggest mistake of my life. the engagement is higher than the stocker, which was already high, and adjusting the clutch pedal does nothing but bring the clutch closer to me. It was already hard enough to come off the clutch fast in the stock location because i'm 6'4" and have long legs, and big feet. I can't shift at redline or higher in any gear. It just locks me out until the revs drop below redline.
I know this topic has been discussed to death, but what i don't get is why doesn't somebody do something to fix it????? is there no way to stop this problem? Some guy from one of the clutch companies told me once that it's just something that happens...can't stop it. bull****. i NEVER had a problem with the stocker so obviously it's possible to make a clutch that doesn't do this.
I should have just replaced the stocker with another stocker. Anybody want to buy an Exedy stage 1 clutch? and where can i get a new stocker besides the dealership?
I know this topic has been discussed to death, but what i don't get is why doesn't somebody do something to fix it????? is there no way to stop this problem? Some guy from one of the clutch companies told me once that it's just something that happens...can't stop it. bull****. i NEVER had a problem with the stocker so obviously it's possible to make a clutch that doesn't do this.
I should have just replaced the stocker with another stocker. Anybody want to buy an Exedy stage 1 clutch? and where can i get a new stocker besides the dealership?
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If you dont mind me asking, who installed the clutch for you? I have installed many exedy stage 1 clutch kits with out any lock out problems....At least up to the stock redline. Also, which fluid and flywheel did you end up using?
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From: Baton Rouge, Louisiana
anybody have any suggestions? i'm about ready to just go to the dealership and pay them whatever they want to put another stocker in. it will be a rip off, but it would be worth it to have the car running the way it used to. ****, the stocker lasted 65k miles. and that was with me learning to launch it, and toasting it a few times lol stock would be fine...it would just suck to have to basically replace a brand new clutch because of a problem that shouldn't happen anyway.
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From: Baton Rouge, Louisiana
because the car is basically stock. no need for anything bigger. i plan to mod it more, so i wanted something that could handle the mods once they get there. Exedy stage 1 seemed perfect....until i got it in the car
The Exedy stage 1 is basically just like a stock clutch except a small increase in clamp load which isn't going to cause lockout. So if you are experiencing lockout that wasn't there before with the stock, it isn't the design of the clutch.
Rather than give the usual short list of common causes, let's walk through all the possibilities together. Because for whatever reason ACT gets blamed for lockout, in spite of it occuring on just about every clutch manufacturer, I have gone through this many times. I think for everyone else's benefit, this time I will go to the trouble of a more complete explanation. The design is really simple and the principles are not hard to understand. I will try and put it in general terms to include other clutches as well. Please excuse me if some of it seems too elementary.
Basics: The flywheel and pressure plate bolt together and spin with the engine while the disc (clamped between them) spins the input shaft of the trans. When you press the pedal down the release bearing pulls the diaphragm spring which allows the casting of the pressure plate to lift away from the disc. The straps are what basically insure that the casting lifts to follow the diaphragm spring. Here is a link to a simple interactive illustration where you can see the clutch engagement/disengagement: http://auto.howstuffworks.com/clutch1.htm. Keep in mind that the illustration is of a push type clutch, not a pull type.
In a nutshell, when you have any sort of drag or "lockout" you have to look at what is possibly continuing to drive the input shaft when the clutch is supposed to be disengaged.
Aside from damage or install errors, many times this is simply a matter of not having enough air gap around the disc. You will notice with Prostock cars and other drag cars, they use a line-lock to prevent the car from creeping forward as they rev the engine on the line. At idle and lower rpm the car is fine, but at high rpm they will tend to creep forward. They adjust the clutch air gap and line-lock brake pressure very precisely to prevent the car from creeping and yet still allow the car to bump forward in the lights. Fortunately they don't have to use the clutch while shifting. If they had conventional syncro transmissions rather than clutchless shifting transmissions, they would also have high rpm shifting issues. The point is this: More air gap is needed at high rpm to get full disengagement. This need for more air gap is from increased windage around the disc, or crankshaft flex at high rpms which cannot be avoided. Here are some possibilities causing inadequate air gap on the EVO and most other cars:
1. Engagement point is too low - If the clutch engagement point at the pedal is adjusted too low, the casting of the pressure plate will not lift enough.
2. Heat damage - More adjustment is needed than normal because the surfaces are no longer flat.
3. Increased friction - If the clutch linkage, release bearing, etc doesn't operate smoothly due to wear or lack of lubrication, then it takes more pedal travel to release which reduces air gap.
4. Loose pressure plate bolts - If the pressure plate isn't torqued down adequately, then it will take more travel to release.
5. Lack of lubrication on the disc splines - Although the pressure plate may lift from the disc, if the disc doesn't slide freely on the splines, the disc will not lift freely away from the flywheel surface.
6. Drive straps - If the straps of the pressure plate do not lift the pressure casting away from the disc for whatever reason (damage or design problem) then air gap is obviously affected. For this reason ACT uses stronger drive straps designed for increased force lifting the casting.
7. Loose flywheel - This will not last too long before the bolts shear off forcing you to fix it anyway.
8. Bad crankshaft thrust bearings - The crank is able to move back and forth which is obviously not a good thing.
9. Air in the hydraulics (including bad cylinders) - I almost forgot since this is so basic.
Other possibilities:
1. Heavy disc design. A smaller solid center disc is much more responsive than a larger spring center disc. A full surface iron disc is much heavier than an organic, etc.
2. Floaters dragging (twin disc) - In cases where the floaters do not freely slide on their post, either from poor design or from heat damage, then they will keep the discs from releasing.
3. Bad pilot bearing (obviously non-EVO since they don't have one) since this binding will cause the pilot shaft to spin independent of the engine.
4. Bent disc - Usually damaged by hanging the transmission on the splines during installation by mistake.
5. Release bearing not attached completely to pressure plate - Usually also includes pulsation through the clutch pedal and a muddy vaque feel. This doesn't last too long before the center peices fall apart.
OK, my fingers are tired and it's Father's day so I think I will stop here. I am sure I missed at least a couple weird possibilities, but that should cover at least 95%.
Rather than give the usual short list of common causes, let's walk through all the possibilities together. Because for whatever reason ACT gets blamed for lockout, in spite of it occuring on just about every clutch manufacturer, I have gone through this many times. I think for everyone else's benefit, this time I will go to the trouble of a more complete explanation. The design is really simple and the principles are not hard to understand. I will try and put it in general terms to include other clutches as well. Please excuse me if some of it seems too elementary.
Basics: The flywheel and pressure plate bolt together and spin with the engine while the disc (clamped between them) spins the input shaft of the trans. When you press the pedal down the release bearing pulls the diaphragm spring which allows the casting of the pressure plate to lift away from the disc. The straps are what basically insure that the casting lifts to follow the diaphragm spring. Here is a link to a simple interactive illustration where you can see the clutch engagement/disengagement: http://auto.howstuffworks.com/clutch1.htm. Keep in mind that the illustration is of a push type clutch, not a pull type.
In a nutshell, when you have any sort of drag or "lockout" you have to look at what is possibly continuing to drive the input shaft when the clutch is supposed to be disengaged.
Aside from damage or install errors, many times this is simply a matter of not having enough air gap around the disc. You will notice with Prostock cars and other drag cars, they use a line-lock to prevent the car from creeping forward as they rev the engine on the line. At idle and lower rpm the car is fine, but at high rpm they will tend to creep forward. They adjust the clutch air gap and line-lock brake pressure very precisely to prevent the car from creeping and yet still allow the car to bump forward in the lights. Fortunately they don't have to use the clutch while shifting. If they had conventional syncro transmissions rather than clutchless shifting transmissions, they would also have high rpm shifting issues. The point is this: More air gap is needed at high rpm to get full disengagement. This need for more air gap is from increased windage around the disc, or crankshaft flex at high rpms which cannot be avoided. Here are some possibilities causing inadequate air gap on the EVO and most other cars:
1. Engagement point is too low - If the clutch engagement point at the pedal is adjusted too low, the casting of the pressure plate will not lift enough.
2. Heat damage - More adjustment is needed than normal because the surfaces are no longer flat.
3. Increased friction - If the clutch linkage, release bearing, etc doesn't operate smoothly due to wear or lack of lubrication, then it takes more pedal travel to release which reduces air gap.
4. Loose pressure plate bolts - If the pressure plate isn't torqued down adequately, then it will take more travel to release.
5. Lack of lubrication on the disc splines - Although the pressure plate may lift from the disc, if the disc doesn't slide freely on the splines, the disc will not lift freely away from the flywheel surface.
6. Drive straps - If the straps of the pressure plate do not lift the pressure casting away from the disc for whatever reason (damage or design problem) then air gap is obviously affected. For this reason ACT uses stronger drive straps designed for increased force lifting the casting.
7. Loose flywheel - This will not last too long before the bolts shear off forcing you to fix it anyway.
8. Bad crankshaft thrust bearings - The crank is able to move back and forth which is obviously not a good thing.
9. Air in the hydraulics (including bad cylinders) - I almost forgot since this is so basic.
Other possibilities:
1. Heavy disc design. A smaller solid center disc is much more responsive than a larger spring center disc. A full surface iron disc is much heavier than an organic, etc.
2. Floaters dragging (twin disc) - In cases where the floaters do not freely slide on their post, either from poor design or from heat damage, then they will keep the discs from releasing.
3. Bad pilot bearing (obviously non-EVO since they don't have one) since this binding will cause the pilot shaft to spin independent of the engine.
4. Bent disc - Usually damaged by hanging the transmission on the splines during installation by mistake.
5. Release bearing not attached completely to pressure plate - Usually also includes pulsation through the clutch pedal and a muddy vaque feel. This doesn't last too long before the center peices fall apart.
OK, my fingers are tired and it's Father's day so I think I will stop here. I am sure I missed at least a couple weird possibilities, but that should cover at least 95%.
very nice info...
so what do you think could be wrong in my situation....?
took my car to Cal Speedway (AutoClub) and was having grinding issues when shifting into 5th gear at 7000rpm in 4th... fresh Redline fluids where used throughout the entire driveline...
so what do you think could be wrong in my situation....?
took my car to Cal Speedway (AutoClub) and was having grinding issues when shifting into 5th gear at 7000rpm in 4th... fresh Redline fluids where used throughout the entire driveline...
I gave you most of the options. So now you have to consider which ones may be applicable and test it out. It's kinda hard to do over the keyboard. The clutch works the same in all gears so if it only does it in one gear then either the trans is just extra sensitive in that gear to what is a clutch problem or the syncros are going out.
hey ODUB, i saw you called but have been busy all weekend with cars (8 cars in 2 days 
).
anyway, feel free to give me a call tomorrow again if you want. otherwise, my advice, i had the stock clutch on my car, and could never ever shift from 1st to 2nd. it would lock me out every time. after switching to the ACT, it was not as bad, but still on the high RPM shift i could get lockout. i think read numerous people saying the front motor mount helps shifting. after replacing the front motormount with a poly motormount, i have never been locked out of a gear again. i use the front motormount and the ingalls engine damper now, and with the 35r revving to 8k rpm, my ACT clutch can still shift just fine. the poly motor mount is 50 dollars... having the dealer do your clutch back to stock one is going to be 1500+
). anyway, feel free to give me a call tomorrow again if you want. otherwise, my advice, i had the stock clutch on my car, and could never ever shift from 1st to 2nd. it would lock me out every time. after switching to the ACT, it was not as bad, but still on the high RPM shift i could get lockout. i think read numerous people saying the front motor mount helps shifting. after replacing the front motormount with a poly motormount, i have never been locked out of a gear again. i use the front motormount and the ingalls engine damper now, and with the 35r revving to 8k rpm, my ACT clutch can still shift just fine. the poly motor mount is 50 dollars... having the dealer do your clutch back to stock one is going to be 1500+
Joined: Apr 2005
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From: somewhere testing various tires, brakes, and suspensions.
hey ODUB, i saw you called but have been busy all weekend with cars (8 cars in 2 days ).
anyway, feel free to give me a call tomorrow again if you want. otherwise, my advice, i had the stock clutch on my car, and could never ever shift from 1st to 2nd. it would lock me out every time. after switching to the ACT, it was not as bad, but still on the high RPM shift i could get lockout. i think read numerous people saying the front motor mount helps shifting. after replacing the front motormount with a poly motormount, i have never been locked out of a gear again. i use the front motormount and the ingalls engine damper now, and with the 35r revving to 8k rpm, my ACT clutch can still shift just fine. the poly motor mount is 50 dollars... having the dealer do your clutch back to stock one is going to be 1500+
). anyway, feel free to give me a call tomorrow again if you want. otherwise, my advice, i had the stock clutch on my car, and could never ever shift from 1st to 2nd. it would lock me out every time. after switching to the ACT, it was not as bad, but still on the high RPM shift i could get lockout. i think read numerous people saying the front motor mount helps shifting. after replacing the front motormount with a poly motormount, i have never been locked out of a gear again. i use the front motormount and the ingalls engine damper now, and with the 35r revving to 8k rpm, my ACT clutch can still shift just fine. the poly motor mount is 50 dollars... having the dealer do your clutch back to stock one is going to be 1500+