RPS Twin Plate Carbon-Carbon Clutch Experiances

[MR2]

Soooo, I got one of these a few months ago, finally got to installing it along with a whole heap of other drivetrain gear (the full SCE Kit) and have been driving it around for a few weeks.

The Good:
-It grips like shit to a carpet if you drop it.
-if you get it right, it does have a decently smooth engagement.
-when driven in anger it just works...clunk and the engine is 100% connected to your gearbox, my last clutch was pretty bad or annoying in that you let the clutch out and it felt like it took a few seconds for the plates to fully grab.

The bad:
-it was very much on off until the first time I dropped the clutch at 5krpm :|
-I'm guessing I warped the plates installing the box or something as it does not always completely disenguage the clutch when the pedal is all the way down...stays engaged enough to actually pull the revs down a fair amount.
-Slight honk just as the clutch is engaging, other wise only a faint hiss.


Can anyone else who's had one of these let me know if their experiances are similar? I suspect that when installing the clutch I did not lube the input shaft enough which is why the clutch plates are sticking....I also suspect I got some oil on the plates themselves (even through I was fairly careful) which is why they are a bit more grabby than I expected

[MR2]

I've shot off an email to RPS to ask about what I've been doing wrong, I might look at after the next meet(29th), re-installing the clutch....alot of stuffing around just to get the clutch out though :|

I have two of these clutch's so in the next few months I need to send the second one out for refurb too (it's the old style, so needs the upgrade to the alu plates)

[mh3kgt]

I've shot off an email to RPS to ask about what I've been doing wrong, I might look at after the next meet(29th), re-installing the clutch....alot of stuffing around just to get the clutch out though :|

I have two of these clutch's so in the next few months I need to send the second one out for refurb too (it's the old style, so needs the upgrade to the alu plates)

Ah, hogwash, just save yourself the hassle and send me your extra clutch :p

[MR2]

You don't want it! it's the explody kind :p

[Erron Spalsbury]

I don't have THAT clutch, but do have a twin disc. Your experiences are pretty much exactly what a twin disc does. Like it? I love mine for sure.

[MR2]

it'd be great with the exception of the non-disengaging :) hopefully I get it sorted out shortly.

[Erron Spalsbury]

The only time I've ever seen one not disengage all the way, the fingers on the cover were over extended by to much clutch fork throw. Are you running a hydraulic throw out bearing or stock fork?

[MR2]

Stock fork? I assumed that his clutch was designed for our stock system? I have seen the hydraulic throw outs but figured it was not needed?

[J. Fast]

You can implement a HTOB on any clutch setup on a 3/S. The biggest benefit of a HTOB is a uniform load distribution to the pressure plate fingers. Instead of using a fork setup which is a hinge setup optimized with specific geometry you're using a piston with a uniform load distribution to the pressure plate fingers. The stock clutchfork is in the shape of a "C" which will not provide equal load distribution on the side of the TOB not being supported because it's on the open end of the fork. A HTOB shifts smoother and engages easier because the pressure being distributed to the pressure plate is perpendicular and uniformly distibuted to the fingers instead of compounding hinges. The stock clutfork setup is based on the geometry of 3 pivot points which would be the slave to fork, pivot ball, and fork to TOB. Three pivot points make for a lot of complex angles and a lot of problems with equal pressure plate load distribution which causes clutch engagement issues with heavy pressure plates. You would really enjoy a piston based TOB with your setup and probably have less of a hard time with engagement with a with a twin disc or any heavy clutch setup.

[MR2]

Righty o, sooo anyone done this yet? reading up on it it seems that most people have to get the throw out to specifically match their application, one guys was saying he spoke to tilton at length to get the right thing fitted. essentially this means getting the throw out distance's right?

lastly, how much harder is it to get your gearbox out with the fancy pants throw out on? I assume you'd need to disconnect the lines and get oil everywhere, is there anything fancy about re-bleeding the clutch after you reconnect it? just brake fluid? it would be nice to avoid having to re-attach all the spagetti attached to the stock clutch slave cyl.

[J. Fast]

The setup is very easy. Use this for a guide. It's all going to be based on your clutch style and the distance from the pressure plate fingers to the bellhousing stop. http://www.tiltonracing.com/ins/98-1110.pdf

[MR2]

oooook I might look into the Erron flywheel in a few months....will give the RPS one last try after I pull it out and relub it etc

[Mitsuman03]

If rob can't answer your question, ask all the questions you can in this thread, and ill answer them for you. Ill start off by this.

The oil you got on your clutch, i wouldn't worry to much about it...ive submerged mine in oil multiple times from when my transmission had exploded. The oil will burn out of the disk's if you hot lap the clutch..(meaning ride it out). Back in the day, these clutches used to be like a button, either on or off...(much worse then what you have today), i found that with a little oil on they seemed to be easier to drive..eventually the oil would burn up.

Next, DO NOT HANG your trans off the shaft when your installing it..meaning no breaks...support it from the top, i know its a bitch, and every one seems to take breaks and kinda just let's it "hang" there tell you get your next breath....THIS WILL damage your disks, it will stress them and start to hair line fracture them. Eventually the'll come apart.

Slip the bitch....slip it the best you can when you shift..your not going to wear it out. When your daily driving, engage it as low as possible, i know its hard, i know its a cunt, but you'll get used to it.

If you race, NO DIRECT ENGAGEMENT...do not rev and drop the pedal...you will hurt your driveline. Slipping this clutch is your friend, even threw second gear if your putting down alot of power, ive smashed open my transmission from not shifting lightly into second before.

Grease your TOB when you re-install it.

Adjust your clutch pedal, you want it engaging closer to the top that way its "fully" out when you shift.....or you'll put a hurt on your syncros.

Your bell housing, please take the time to have a brace installed, its such a cheap investment, for such a great line of protection...many will argue that if your not making big power you dont need it. Thats a line of horse shit..if you slip on your clutch and drop it..the to shafts inside the transmission WILL want to "pull" away from each other...thats what cause the bell housing to crack....

[J. Fast]

The shafts that a hoop brace lock may be spinning in different directions but the axial loading and the couples are directed towards the endcover. I'm not sue who said they were trying to pull apart but helical gears mesh patterns are designed to pull the gears together. On another note, the destruction on our transmissions comes from proven vibration studies published by Mitsubishi and Mazda Motor Corporations in a 2007 Journal of Advanced Mechanical Engineers publication called "Vibration Analysis of Helical Gears....". The things people have said about bracing and etc is pure myth. It's all about tooth engagement, backlash, axial loading on the end bearings, and fluid. The gears in our transmissions have a natural vibration that's transferred to the shafts. There are three types of excitiations, the first is called displacement, the second is called parametric, and the last is a moving load on the end bearings. The only way to make sure they don't blow from big power is to manage the helical gear excitation by preloading the gears correctly and to keep the end bearings from compressing or moving.

[CoopKill]

The shafts that a hoop brace lock may be spinning in different directions but the axial loading and the couples are directed towards the endcover. I'm not sue who said they were trying to pull apart but helical gears mesh patterns are designed to pull the gears together. On another note, the destruction on our transmissions comes from proven vibration studies published by Mitsubishi and Mazda Motor Corporations in a 2007 Journal of Advanced Mechanical Engineers publication called "Vibration Analysis of Helical Gears....". The things people have said about bracing and etc is pure myth. It's all about tooth engagement, backlash, axial loading on the end bearings, and fluid. The gears in our transmissions have a natural vibration that's transferred to the shafts. There are three types of excitiations, the first is called displacement, the second is called parametric, and the last is a moving load on the end bearings. The only way to make sure they don't blow from big power is to manage the helical gear excitation by preloading the gears correctly and to keep the end bearings from compressing or moving.

So you are saying the bell housing brace is unnecessary?

[J. Fast]

It's only necessary when you utilize a clutchfork engagement design.

The stock clutchfork and slave setup should be avoided when you switch to a twin disc because the clutch fork pivot point and lever (clutchfork) for our cars are fixed positon.

The geometry is not designed for the distance and leverage required to uniformly depress twin disc pressure plate fingers which is typically why a large number of people don't have consistent successive shifts and have engagement problems.

[MR2]

I have the bell housing brace and the end plate, would not be upgrading the clutch without them!

Pulled the clutch and re-lubed the shafts...will see how we go this time.

[Mitsuman03]

The shafts that a hoop brace lock may be spinning in different directions but the axial loading and the couples are directed towards the endcover. I'm not sue who said they were trying to pull apart but helical gears mesh patterns are designed to pull the gears together. On another note, the destruction on our transmissions comes from proven vibration studies published by Mitsubishi and Mazda Motor Corporations in a 2007 Journal of Advanced Mechanical Engineers publication called "Vibration Analysis of Helical Gears....". The things people have said about bracing and etc is pure myth. It's all about tooth engagement, backlash, axial loading on the end bearings, and fluid. The gears in our transmissions have a natural vibration that's transferred to the shafts. There are three types of excitiations, the first is called displacement, the second is called parametric, and the last is a moving load on the end bearings. The only way to make sure they don't blow from big power is to manage the helical gear excitation by preloading the gears correctly and to keep the end bearings from compressing or moving.

Thats great that some engineers decided to rediscover there faults 20 years after designing a cast aluminum transmission. What you forgot to mention, and what they did not evaluate is that these transmission had no intentions to put down and handle as much power as some do today, and like any other metal that's abused over and over again after a period of long time, they weaken. For there time, they where slightly over engineered part, and where strengthened to the best of there ability..(hence the 3 ribs that seem to "strengthen" the walls of the bell housing.....hmm.wonder why they put those there? When you have a force of uncommon strength being applied at such a speed, when the gears mesh together in abrupt force, the unit as a whole will flex, causing them to push apart from each other and "mis aligning' the teeth...well..if there's no room for these errors being that the tolerance is oh so tight, i guess the only way is in the "away" direction..causing them to push apart.....well..guess what there going to push into?

Also, if you COULD preload these gears...COULD YOU IMAGINE the destruction that would be caused it a high speed, when the "pre load" is unnecessary? There wouldn't be a fluid in the world that could keep them from burning up. Don't believe everything you read, until you can apply to the reality of physics being questioned.






So you are saying the bell housing brace is unnecessary?

Its been proven for years that it has saved many transmission...he can do w/e he wants to his car, if your balling and can replace transmissions left to right...hey can believe its a myth.




It's only necessary when you utilize a clutchfork engagement design.

The stock clutchfork and slave setup should be avoided when you switch to a twin disc because the clutch fork pivot point and lever (clutchfork) for our cars are fixed positon.

The geometry is not designed for the distance and leverage required to uniformly depress twin disc pressure plate fingers which is typically why a large number of people don't have consistent successive shifts and have engagement problems.

O man..the clutch fork theory, really..again 10 years down the road? Ya, this has been looked into, just not discussed often enough b/c it wasn't sought out to be a major problem..and it really isn't..nor is it the cause of the reason as to why the transmission crack. . Yes, is not an "exact" science, but its effective. The clutch fork does sit on a pivot ball, (that many tend to forget to grease), yet its design may not be perfect for the application after molding, but it does distribute an almost balanced force. The TOB does sit on two pivot clips on the fork, when the slave cylinder press and push's the fork, the fork then pivots on the ball, pushing in, as it equally pulls up from the center of the TOB. Its not shift issues or engagement problems caused by this, that's strictly related to the pressure and the pedal's travel. In order to utilize a twin disk you have to have it pull the full distance, hence why i mentioned to adjust the pedal to catch as close to the top as possible. That will give you full travel. To over compensate this, eliminating all the rubber/plastic components in the shifting system's help to tighten up the looseness, also securing the cables properlly..




I have the bell housing brace and the end plate, would not be upgrading the clutch without them!

Pulled the clutch and re-lubed the shafts...will see how we go this time.


Your smart for doing the bracing.....

[MR2]

Your smart for doing the bracing.....

I'm just not rich...I can't afford a new GB :p Cheaper to install the plates and endcase than to blow up expensive diffs!

Gotta figure out how to get the gb up tonight...hate that part :( getting it to NOT fall off my jack is always a challange.

[Mitsuman03]

I'm just not rich...I can't afford a new GB :p Cheaper to install the plates and endcase than to blow up expensive diffs!

Gotta figure out how to get the gb up tonight...hate that part :( getting it to NOT fall off my jack is always a challange.



Engine hoist and ratchet straps..slide the trans under the car 1st, then attach the ratchet straps around it, lift with hoist...easy as cake..a

[Erron Spalsbury]

At what power levels are you guys recommending the end case brace?

[MR2]

I wish I had a hoist...life would be sooooo cruisy.(but I have no room for one in my single car garage)

instead I lifted it with two jacks and held it with one of them while snuggling it in :) fitted like a glove :) will test it tonight

[Mitsuman03]

At what power levels are you guys recommending the end case brace?

I wouldn't place it at a power level, rather your intentions of usage. I have not done this upgrade yet, although i may actually go the billet route.

[MR2]

yeah, pretty much only needed for dragging. I seem to remember Matt said he created his one when he blew out his end case bouncing off the rev limiter in gear.

[MR2]

Back to being on topic:

over the last two days, I pulled the GB re-lubed the shafts and re-installed the clutch. I don't know why but everything this time was perfect, easy to get the GB back up, easy to get the gb to slide into the clutch, easy to bolt back up, and low and behold at the end of it the clutch is now perfect.

of all rofl's, my second gear syncro is now gone AGAIN...guess I'll get it replaced the next time the box is out...AGAIN.

anyway the clutch is still a little shuddery if you try to do a reallly smooth engagement however when you learn(or when I) to match the Accellerator with letting it out fast (as opposed to being a pansy) it's fine.

[J. Fast]

What you forgot to mention, and what they did not evaluate is that these transmission had no intentions to put down and handle as much power as some do today, and like any other metal that's abused over and over again after a period of long time, they weaken. For there time, they where slightly over engineered part, and where strengthened to the best of there ability..(hence the 3 ribs that seem to "strengthen" the walls of the bell housing.....hmm.wonder why they put those there? When you have a force of uncommon strength being applied at such a speed, when the gears mesh together in abrupt force, the unit as a whole will flex, causing them to push apart from each other and "mis aligning' the teeth...well..if there's no room for these errors being that the tolerance is oh so tight, i guess the only way is in the "away" direction..causing them to push apart.....well..guess what there going to push into?



I thought I'd take the time to shoot down the hype on the billet end cover and so forth. Again, the weakness in our transmissions is in the bearing design. It has nothing to do with the type of material the transmission is composed of or it being "weak". It has to do with maint and setting it up in spec. Want to make big power? You're going to increase the gearmesh excitation freq's and compress the end bearings. Everytime you launch it the end bearing shim heights/ preleoads become a maint item and regardless of wether or not you have a billet end case the preloads and gearmesh patterns will need to be checked just like a Nascar performance engine is stripped and rebuilt every time it's ran.

It has been proven that all meshing gears generate harmonics and vibrations. In our case we have a helical gear design and the gearmesh vibrates. The vibration should not be confused with transmission whine from the style of tooth engagement but an excitation from the gear mesh. I will state the simple findings and you can run with your idea or take the answer in the transmission design failure report I have studied along with a number of three dimensional gear vibration analysis, multi-stage gear engagement reports, Houjoh's gear-vibration study and findings models, Kato's noise defraction and reflection studes on drivetrain harmonics, and my personal experience in rebuilding these drivetrains. I am quite familiar with DSM and 3/S drivetrains and have performed a number of complete disassembly, reassembly, regear, and so forth.

IMO the design flaw has nothing to do with the strength of the bellhousing and end cover. It has to do with the compressability of the end bearings. OEM end bearings will compress long before the end cover or bellhousing will separate (explode) from helical mesh tilting. It is aproven scientific fact that torque ripple in motors, improper bearing race shim position, and fluctuations in tooth stiffness cause excitation during gear meshing. This mesh excitiation propigates from the gearshafts to the bearings (where it is converted into a bearing force), excites the gearbox, and generates gear-vibration noise which is radiated from the surface of the gearbox. The "tuning fork" vibration traveling down the input, intermediate, and output shafts sends endstress to the bearing races and changes the preload which alters the gearmesh which in turn amplifys the gearmesh vibration. The end result is the gear teeth bind and the vibration increases and eventually the force from improper mesh blows the housing or shears the gear teeth and the transmission binds on itself and blows.

Of course we are all entitled to our opinions. I feel my opinion is well researched and founded. Here is a screen shot of some of my research.

http://i788.photobucket.com/albums/yy163/JFastMotorsports/hELICAL.jpg

[CoopKill]

I thought I'd take the time to shoot down the hype on the billet end cover and so forth. Again, the weakness in our transmissions is in the bearing design. It has nothing to do with the type of material the transmission is composed of or it being "weak". It has to do with maint and setting it up in spec. Want to make big power? You're going to increase the gearmesh excitation freq's and compress the end bearings. Everytime you launch it the end bearing shim heights/ preleoads become a maint item and regardless of wether or not you have a billet end case the preloads and gearmesh patterns will need to be checked just like a Nascar performance engine is stripped and rebuilt every time it's ran.

It has been proven that all meshing gears generate harmonics and vibrations. In our case we have a helical gear design and the gearmesh vibrates. The vibration should not be confused with transmission whine from the style of tooth engagement but an excitation from the gear mesh. I will state the simple findings and you can run with your idea or take the answer in the transmission design failure report I have studied along with a number of three dimensional gear vibration analysis, multi-stage gear engagement reports, Houjoh's gear-vibration study and findings models, Kato's noise defraction and reflection studes on drivetrain harmonics, and my personal experience in rebuilding these drivetrains. I am quite familiar with DSM and 3/S drivetrains and have performed a number of complete disassembly, reassembly, regear, and so forth.

IMO the design flaw has nothing to do with the strength of the bellhousing and end cover. It has to do with the compressability of the end bearings. OEM end bearings will compress long before the end cover or bellhousing will separate (explode) from helical mesh tilting. It is aproven scientific fact that torque ripple in motors, improper bearing race shim position, and fluctuations in tooth stiffness cause excitation during gear meshing. This mesh excitiation propigates from the gearshafts to the bearings (where it is converted into a bearing force), excites the gearbox, and generates gear-vibration noise which is radiated from the surface of the gearbox. The "tuning fork" vibration traveling down the input, intermediate, and output shafts sends endstress to the bearing races and changes the preload which alters the gearmesh which in turn amplifys the gearmesh vibration. The end result is the gear teeth bind and the vibration increases and eventually the force from improper mesh blows the housing or shears the gear teeth and the transmission binds on itself and blows.

Of course we are all entitled to our opinions. I feel my opinion is well researched and founded. Here is a screen shot of some of my research.

http://i788.photobucket.com/albums/yy163/JFastMotorsports/hELICAL.jpg

So, what then would be a solution?

[MR2]

Even with all that information I still don't see how you can say the Endcase does nothing, you've mentioned that the end bearings can be compressed...by how much? then what? since we can't actually adjust each of our gears to a double helix and since every gearbox practically in existance has the same design (excluding straight cut due to noise) it seems to me that the end case is a reasonable solution to the problem and while you think the problem should not exist it obviously has happened to a few people (see matt's threads)

at the very least it's shiny ;)

[J. Fast]

When you start to develop power over say 800 to the wheels routinely check your gearmesh patterns, backlash, and preloads for all drivetrain components. Maintain them like a racecar, because effectively that's what you own with that kind of power. Service it every time you launch the piss out of it. The original car owner on our CC team owns a 1000+hp DSM. For longer than I've owned my car he's ran a stock trans, and rebuilds it 5-10 times a season.

When you make big power inherent maint comes along with it if you drive your car for the purpose it was built for... To put down power. You could choose to drive it like a pussy and show it off at shows and the first time you are tested it will break because you overlooked some big power maint item because it was built for show and not maintained for go. Most of teh folks I run with are constantly servicing and working on their respective cars. Nearly everytime we comeback from the track we're taking something apart and maint something else, and our cars continue to develop more an more power. The more power they make the more shit we have to take apart to doublecheck everything. Our maint has increased but nothing is breaking. So it all comes down to maint and preperation.

A simple test would be asking anyone making over 600hp how often they nut and bolt their car. Myself and anyone with common sense should do it every time the car is driven. You'd be surprised how much everything shifts and moves with that kind of power.

[MaxClass]

Check out this excellent video on properly adjusting your clutch. I learned a lot I did not know regarding adjusting the pedal linkage and using the slave cylinder to check for the exact settings on the pedal adjustments. Well worth the read.

Could also be the problems with the clutch not fully disengaging as it should. Every one would do well to watch this one.

Jacks Transmissions LLC — Tech Articles (http://www.jackstransmissions.com/pages/tech-articles)

Good Luck.

[CoopKill]

Nice vid, Thanks!

[MR2]

just a last minute bump on this, been running the car occasionally and the clutch is now perfect :) very happy! also glad I was very very careful to grab the latest revision of the clutch...screw loosing a GB to the old style ;(

[J. Fast]

My guess is most of the failures were probably related to the install. The alignment is so crucial. You bind the trans while it's going in, have it pitched, or out of alignment even a little before the bellhousing hits the dowels and the clutch is done. That's a huge piece of the puzzle with twin discs. I actually was taking with Dan V. over at Tilton Engineering yesterday regarding the reason why center hubs and twin discs usually fail. He mentioned for the most part its alignment. There's a lot of teeth to align and not alot of room to get that trans in there with the alignment tool seated. You gotta go slow.

Glad it worked out for you man! Can I see a launch vid?

[MR2]

I think that your partially right...2 parts to this

yes people are probably screwing up the install...BAD PEOPLE

but I think the clutch needs to have a REASONABLE amount of tolerance of people's install methods, and I suspect the old steel plates would bend while the thicker alu don't...

It's SO DAMN important to have the new plates.

[MR2]

and I'm still not balsy enough to dump it :p

let alone feeling like spending money on a hero cam as opposed to replacing the god damn teins :p

[GTOJOE]

Come on dude you have like $10k tied up in the trans. I'm sure it will hold whatever you can throw at it. Your weak points now are your drive shafts :p

[wraith]

I dont trust a CC---not durable enough for me. I have lots of luck with standard stuff and they hold plenty of power if you have a decent driving technique

[J. Fast]

Most clutch setups have different disc, floater, and hub options. I know twin disc RPS can retro with Tilton and Clutchmaster disc packs. It's a matter of finding the right disc to suit your driving style and application. Long term maint with a nice twin disc clutch is cheap. Mine will only cost $200 to change forever. Never will ever need a new flywheel or pressure plate. I love that :)