What causes High RPM lockout on ACT clutches?
Evolving Member
Joined: Nov 2006
Posts: 372
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From: Houston, TX
i've talked to Daryl Sampson the Sales & Marketing Manager at ACT and here are some of his thoughts about high rpm lock out...
"Now about lock out. Lock out occurs when there isn't enough air gap between the disc pressure plate and the flywheel to allow the clutch to disengage at high rpm. The reason the above occurs are as follows: bent disc (hanging the transmission off the input shaft - install error, warped pressure plate, or flywheel - excessive heat - driver error as a result of slipping the clutch too much and a mis-adjusted or not even adjusted clutch - user/installer error."
other thoughts from Daryl...
"For as long as I've been in this industry people seldom admit that they are beating the hell out of a part and caused it to fail, mechanics seldom admit that they have no clue about what they are doing but will instead hide behind ASE certifications etc. and their are two sides to every story. We've been in business for 15 years, making a clutch for a Evo is not that much different than making a clutch for a STI or a RX7 or a Honda in pricinple. In fact the unit in the STI is the same size and very similar in design to the Evo and we don't hear of these issues on those cars."
"The Evo is one of our most popular kits, that's not by accident. Neither is the fact that we are an industry leader in the market. That only happens by hard work, and the dedication to not only make and design the best parts but also the dedication to stand behind them. I'm sure if you ask most of the people in the thread if they took the time to send the parts in to ACT to have the parts looked at by us, called us or taken their car to a reputable Evo shop to have it adjusted most will tell you no."
"The front motor mount helps a great deal with helping with engine movement and mis shifts which people also confuse with lockout, but since the cause of lock out has nothing to do with engine movement that in itself will not correct the problem."
"So to avoid lock out:
Have a qualified (read Evo specialist) install your clutch.
Have it adjusted via the threaded rod if it it's required. There are write ups in the how to section.
Know how to launch your car. By doing that part right you will avoid heating up the parts and causing lock out."
I'm sure of all people this guy knows....
"Now about lock out. Lock out occurs when there isn't enough air gap between the disc pressure plate and the flywheel to allow the clutch to disengage at high rpm. The reason the above occurs are as follows: bent disc (hanging the transmission off the input shaft - install error, warped pressure plate, or flywheel - excessive heat - driver error as a result of slipping the clutch too much and a mis-adjusted or not even adjusted clutch - user/installer error."
other thoughts from Daryl...
"For as long as I've been in this industry people seldom admit that they are beating the hell out of a part and caused it to fail, mechanics seldom admit that they have no clue about what they are doing but will instead hide behind ASE certifications etc. and their are two sides to every story. We've been in business for 15 years, making a clutch for a Evo is not that much different than making a clutch for a STI or a RX7 or a Honda in pricinple. In fact the unit in the STI is the same size and very similar in design to the Evo and we don't hear of these issues on those cars."
"The Evo is one of our most popular kits, that's not by accident. Neither is the fact that we are an industry leader in the market. That only happens by hard work, and the dedication to not only make and design the best parts but also the dedication to stand behind them. I'm sure if you ask most of the people in the thread if they took the time to send the parts in to ACT to have the parts looked at by us, called us or taken their car to a reputable Evo shop to have it adjusted most will tell you no."
"The front motor mount helps a great deal with helping with engine movement and mis shifts which people also confuse with lockout, but since the cause of lock out has nothing to do with engine movement that in itself will not correct the problem."
"So to avoid lock out:
Have a qualified (read Evo specialist) install your clutch.
Have it adjusted via the threaded rod if it it's required. There are write ups in the how to section.
Know how to launch your car. By doing that part right you will avoid heating up the parts and causing lock out."
I'm sure of all people this guy knows....
Due to the fact you are basing all your info on something a SALESMAN told you I do not believe this. As an engineer I learned to never trust sales staff with technical questions. On the surface they seem to know what they are talking about sometimes, but they usually dont. If this guy worked in R&D or he was an ACT design engineer or anything technical then I would be more inclined to believe you.
To the people discussing hard launches and 60ft times that information is completely irrelevant in this thread. The issue isnt with clutches slipping, its lockout at high RPM. Please explain to me how trying to go from 1st to 2nd gear above 7500 RPM has anything to do with the "launch".
Due to the fact you are basing all your info on something a SALESMAN told you I do not believe this. As an engineer I learned to never trust sales staff with technical questions. On the surface they seem to know what they are talking about sometimes, but they usually dont. If this guy worked in R&D or he was an ACT design engineer or anything technical then I would be more inclined to believe you.
To the people discussing hard launches and 60ft times that information is completely irrelevant in this thread. The issue isnt with clutches slipping, its lockout at high RPM. Please explain to me how trying to go from 1st to 2nd gear above 7500 RPM has anything to do with the "launch".
To the people discussing hard launches and 60ft times that information is completely irrelevant in this thread. The issue isnt with clutches slipping, its lockout at high RPM. Please explain to me how trying to go from 1st to 2nd gear above 7500 RPM has anything to do with the "launch".
Last edited by chaotichoax; Dec 4, 2008 at 03:34 PM. Reason: we don't condone talk of street racing
Thats what im trying to say but its irrelevant, other than the fact that a bad launch will put more wear on the clutch than would a good launch with the right amount of slippage.
Due to the fact you are basing all your info on something a SALESMAN told you I do not believe this. As an engineer I learned to never trust sales staff with technical questions. On the surface they seem to know what they are talking about sometimes, but they usually dont. If this guy worked in R&D or he was an ACT design engineer or anything technical then I would be more inclined to believe you.
To the people discussing hard launches and 60ft times that information is completely irrelevant in this thread. The issue isnt with clutches slipping, its lockout at high RPM. Please explain to me how trying to go from 1st to 2nd gear above 7500 RPM has anything to do with the "launch".
To the people discussing hard launches and 60ft times that information is completely irrelevant in this thread. The issue isnt with clutches slipping, its lockout at high RPM. Please explain to me how trying to go from 1st to 2nd gear above 7500 RPM has anything to do with the "launch".
the topic is on high rpm lock out....launching involves slipping of the clutch, which heats up the clutch disc, which may alter the disc by warping it, which it turn greatly effects the shifting performance on your car at high rpm....launching the car and slipping of the clutch does come into play when your having high rpm lockout because the problem could be from a warped disc which could of been from slipping the clutch to long and heating up the disc and warping it
it all comes down to how the clutch works.....if you have lock out problems then that means your clutch isn't disengaging fully....which could be a warped disc or could be a faulty master cylinder not working properly....the clutch needs to be adjusted out as far as it can but don't go to far or the bleeder valve will become blocked and the slave cylinder will not work properly....if your clutch is adjusted correctly you will get the most fluid flow with every push of the clutch...which means youll have the most travel of the push rod on the slave cylinder...which means the most gap between the pressure plate and flywheel....
the organic material that the HDSS is made of heats up easy and will warp easily...more people have lock out problems with the HDSS then the HDG6 because the sprung 6 puck is made of a cerametallic material which has higher heat efficiency so doesnt heat up as easy as the organic HDSS
another thing about the organic material tho is if it is burnt it will bounce back...but thats the material not the warped disc
also another thing that might effect high rpm lock out might be the flywheel you select...i'm not positive but act's flywheel is most likely designed to be combo'd with there clutch kits and exedys flywheels are designed for their clutch kits and so on but i may be wrong but those couple thousands of an inch on the thickness of the flywheel may come it play when disengaging the clutch...
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Joined: Oct 2007
Posts: 152
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From: Lancaster, CA
Due to the fact you are basing all your info on something a SALESMAN told you I do not believe this. As an engineer I learned to never trust sales staff with technical questions. On the surface they seem to know what they are talking about sometimes, but they usually dont. If this guy worked in R&D or he was an ACT design engineer or anything technical then I would be more inclined to believe you.
Being an engineer has nothing to do with what I said in my PM to evane, even though I went to college to be an engineer
and more to do with common sense based on the materials being discussed. We have an engineer here that used to work at Brembo and at Dan Gurney on his Indy car program and he still had to learn about clutches, clutch design and how that relates to what we do at ACT. Your insinuation that someone has to be an engineer or in the technical field to explain something of a technical nature to you that you find credible is a bit much. My comments about lock out can be found on here by simply searching the screen name ACTman on here. ACTman is Dirk the owner and founder of ACT. He has over 30 years worth of experience building clutches and there's still no shortage of keyboard engineers on here that think they know better than him. He's probably forgotten more than 90% of us on here know about clutches and their design.
At no point did evane ask you believe him, he simply posted a PM conversation we had, but as I said above the information can be found by looking up the more "credible" source. In the end it really doesn't matter what the source, there is always someone on here that knows more or just enough to be dangerous or argue or detract from the comments made by someone that is a professional within an industry.
well i have a act xtss clutch installed by myself without ever taking a tranny off before. And 3000 miles later I have never had a locking issue I have shifted over 7000rpms and all I get is some grinding but nothing due to clutch so I am hesitant to believe that it cannot be solved easily.
Former Sponsor
Joined: Oct 2007
Posts: 152
Likes: 1
From: Lancaster, CA
Exactly what I was saying also, just in different words. It all sounds good, but in the end you're still left with a clutch that acts up "no pun intended".
At the very least if the so called driver errors and installer errors should would show up as the same problems in other clutches on the market and they dont. I just find it hard to believe so many people have the problem when the only consistant variable to the equation is the parts being used.
If ACT stood by their product a bit better I might consider taking the chance but I've seem then deny every issue on the planet and blame it on the install or driver. As often as the driver may deny beating on a clutch, most manufactures deny there is any fault in their product.
I wish the EVO community had vendors like we have over in the SRT community. DCR is a prime example.
At the very least if the so called driver errors and installer errors should would show up as the same problems in other clutches on the market and they dont. I just find it hard to believe so many people have the problem when the only consistant variable to the equation is the parts being used.If ACT stood by their product a bit better I might consider taking the chance but I've seem then deny every issue on the planet and blame it on the install or driver. As often as the driver may deny beating on a clutch, most manufactures deny there is any fault in their product.
I wish the EVO community had vendors like we have over in the SRT community. DCR is a prime example.
You can believe what you will but I know that I've personally gone above and beyond our warranty to help customers when it was clear that it is our fault. Mistakes do happen, but it's all in how you deal with them. By the same token if all of our clutches we sold for the Evo weren't good we wouldn't stay in business. I've seen my fair share of mistakes on both sides.
PM any of the vendors on here (that sell a lot of clutches) and I'm pretty certain that the HDSS and the Exedy twin disc are proabably the 2 most popular clutches sold. Taking that into context as far as single disc units go, if there are more of a particular item on the market sold even if there was a problem with less than 2% of the ones sold it would still equal to more of any item that sells significantly less if the lesser selling item had a similar issue. Hopefully that made sense.
i have the act in my car. ive used 2 disk with the same fly and pressure plate. both act. never had a problem. the disk even last about 50 launches at the track with 1.6 60ft. i did have this problem with another clutch that i used a alloy fly. seems like other using the alloy fly also have the problem but ones on the steel dont.
lockout
first of all i am not on here calling anyone a bad driver or bad installer.i am also not saying that i am a professional driver by any stretch.having said that i will say from experience.i had an 89 civic 4 door i put a b16a engine and tranny with act clutch.car grabbed hard and chirped all 5 gears.problem is it didnt disengage all the way all the time.i later found out i was sold the wrong clutch and flywheel combo for my car.not an act problem but rather a wrong part issue.i also had a 92 integra gsr with act clutch worked flawlessly all the time.i currently am running an act with lightweight flywheel and shepracing close ratio tranny.i have NEVER had a problem with lockout.in the 6 mos i have had the act i have shifted from 3rd to 2nd when i was on it hard racing ,didnt mess up the valvetrain or drivetrain this happened once.one time i was getting on it and released the clutch pedal to soon and missed a shift if you didnt know better i would say it was lockout but i know that i lifted the clutch to soon so that was driver error.i know alot of people who run act and NO ONE i know has had problems (mostly honda and acura guys).this is my opinion the act is the best street and strip clutch out there.if you are strictly drag racing i would suggest a dual or triple disc set up but not really for street use.just my opinion
XTSS with prolite flywheel here too! never been locked out even when changing gears flat-shifting at 8000rpm....
I have the clutch around 8000 miles... Except the harder pedal feel, no other ill effects... Redline MT-90 oil and all stock bushings...
I have the clutch around 8000 miles... Except the harder pedal feel, no other ill effects... Redline MT-90 oil and all stock bushings...
I see ACT on the forums and they are always professional and supportive. That being said if I go out and buy a HEAVY DUTY STREET AND STRIP clutch I'm not gonna drive the car like a little old lady. It best be able to cause chipped teeth when shifting at 8k rpm.
Warped this, air gap that, install my ****..... its the clutch. This isn't a problem with the stock clutch. This isn't a problem with exedy stage 1-2 or TD. People running the centerforce, clutchmasters, fidanza, and south bend aren't locking out.
I've run out of fingers and toes counting how many people went from a functional stock clutch to the HDSS and had immediate problems. Then they suck it up and get a twin disk and the problem is gone.
Furthermore its not just lockout that is common on this particular clutch. There are tons of threads about it not disengaging completely even after rod adjustment. I see threads stating you need to readjust the clutch every couple thousand miles. That is crap. Didn't have that issue with the stocker. But wait there is more! The engagement height changes from cold to hot as well. For the low low cost of a couple hundred bucks you might be able to lessen the effect by upgrading bushings, motor mounts, and dampeners but that his horse crap. Some of the cars with these clutches have less than 5k miles. I can see making those recommendations for a 200k mile DSM but an EVO9 ..... no way.
Warped this, air gap that, install my ****..... its the clutch. This isn't a problem with the stock clutch. This isn't a problem with exedy stage 1-2 or TD. People running the centerforce, clutchmasters, fidanza, and south bend aren't locking out.
I've run out of fingers and toes counting how many people went from a functional stock clutch to the HDSS and had immediate problems. Then they suck it up and get a twin disk and the problem is gone.
Furthermore its not just lockout that is common on this particular clutch. There are tons of threads about it not disengaging completely even after rod adjustment. I see threads stating you need to readjust the clutch every couple thousand miles. That is crap. Didn't have that issue with the stocker. But wait there is more! The engagement height changes from cold to hot as well. For the low low cost of a couple hundred bucks you might be able to lessen the effect by upgrading bushings, motor mounts, and dampeners but that his horse crap. Some of the cars with these clutches have less than 5k miles. I can see making those recommendations for a 200k mile DSM but an EVO9 ..... no way.
I was to understand the weight of the disc had something to do with lockout issues but don't take this for fact.
Its just something i read on here one time. What I do know is.
A singledisc adjusted all the way out, wont wear out prematurely and i was told that it would. I have 27k on a 2.3L 37R 500+whp street disc.
Don't even give singledisc lockout a thought unless you plan on revving past 7k. Its not an issue even with stock mounts bushings and everything. If you plan on going past 7k a twindisc is much better this is FACT! The evo transmission is the only transmission i've ever driven that locks out on a single disc. Call shep and ask him what to run
Its just something i read on here one time. What I do know is.
A singledisc adjusted all the way out, wont wear out prematurely and i was told that it would. I have 27k on a 2.3L 37R 500+whp street disc.
Don't even give singledisc lockout a thought unless you plan on revving past 7k. Its not an issue even with stock mounts bushings and everything. If you plan on going past 7k a twindisc is much better this is FACT! The evo transmission is the only transmission i've ever driven that locks out on a single disc. Call shep and ask him what to run