Clutch 101 by Rocket

[Master of the Universe]

CLUTCH 101

INTRO

The clutch is one of the most import component in a high performance build up. No other single component will be used as much by the driver and affect the way the driver interacts with his/her car.

This is posted in the FI forum because I have found this is where alot of members are dead serious about performance and engines found here make a shit load of torque.


MY BACKGROUND

My name is Robert Martin and I have been building Honda engines, trannies, doing swaps, etc. I also have been selling and installing clutches for the past 4 years. I have had the luck to be very good friends with Alex of Action clutch and because of this have seen many many clutches. Here are some things I would like to share with you so you can make a better decision on which clutch to run.


THE PLAYERS

In no particular order:

ACT
ClutchNet
ClutchMasters
RPS
Herson (HC Racing)
Action Clutch
Clutch Specialties


ANATOMY OF A CLUTCH SET UP

This diagram is far from complete but it will help you see what's going on.



Basically the clutch locks the disc onto the flywheel using the diaphram as the loading mechanism. When you push in the diaphram it lifts the FRICTION RING and the CLUTCH DISC is free to spin independantly from the engine so you can change gears without grinding.

Any flex the CLUTCH COVER will hinder the FRICTION RING from releasing the CLUTCH DISC. Currently the only company to offer their own custom CLUTCH COVER (that is affordable) is ACT although OEM FCC or Exedy CLUTCH COVER's work fine.

As you can see if you move the LEVER POINT's closer to the PIVOT POINT the DIAPHRAM will have more leverage and exert more force on the FRICTION RING.
ACT, Clutchmaster, Action, and Hersons do this by machining the LEVER POINT so that the peak of the LEVER POINT is closer to the PIVOT POINT. The side affect of doing this is that it requires you to push on the DIAPHRAM further than you would if the LEVER POINT was not moved. Clutchmasters does a unique thing in that the place spot welds to build up the LEVER POINT's and then do machining to be be able to move the LEVER POINT the furthest.

Another way to increase pressure is to install a stiffer DIAPHRAM. ACT, Action, and maybe RPS does this (I have never seen RPS since they are not popular in LA). ACT has an extra thick 3mm vs. 1.8mm DIAPHRAM that they use in there Extreme pressure plates. This gives good pressure but is on the thick side and has been known to crack due to it's thickness and the hardness of the steel that it is made of. It's very hard steel. It has the highest hardness of any diaphram I've seen.

You can also install another diaphram and have two diaphrams. This is what is called a DUAL DIAPHRAM clutch. Herson, Action, ClutchNet, ClutchSpecialties, and some smaller shops make these. Note: to properly make a double diaphram clutch is not as easy as slapping in another Diaphram. The rivets holding in the DIAPHRAMs must be longer, the FRICTION RING or LEVER POINTS have to be clearanced to make room for the extra DIPHRAM. The only companies I know of that can do this properly is Action and Hersons.

To be continued...

Any of you local to LA and have an old clutch from a company other than Action please contact me so I can have it taken apart for this article.


[Modified by Rocket, 12:17 AM 6/25/2002]


[Modified by Rocket, 10:51 AM 8/24/2002]

[2K_TEG]

Hell YEAH. I was waiting for this. Rocket, looks like you got another star.

you need all though

Edit: My Action Clutch came today. Thanks Rocket.


[Modified by 2K_TEG, 7:25 PM 6/24/2002]

[Crxless]

Good post, very informative. Thanks for taking the time to post something like that.


[Modified by Crxless, 8:50 PM 6/24/2002]

[reXem]

I see that Centerforce is missing from your list...are they no good? I just bought one and it seems great so far and it was reccomended to me a lot

[TurboSedan]

Rocket, that was a great start. I can't wait until you post more. Thanks!

[HXMan]

Definitly worth getting moved up.

[Master of the Universe]

I see that Centerforce is missing from your list...are they no good? I just bought one and it seems great so far and it was reccomended to me a lot

You don't want CenterForce. More bells and whistles than real performance.

[VaporTrail]

the thing is about Centerforce, their calling card if you will, is that the centrifugal weights which make them so great on so many other cars, are not used due to space constraints on Honda cars. So, they are just like any other Honda clutch.

[reXem]

really...damn wish I knew that.... I got their Dual Friction Clutch for 400 bucks canadian after tax....how much power is this clutch gonna hold?

[eddie1681]

rocket

thanks for the info, good job!!!

[BROOD]

Rocket,
What a good start. I would be really interested in seeing your thoughts on a RPS clutch. They use a embossment or ribbing on the diaphram fingers to increase stiffness and help retain lower pedal pressure (at least on the MAX series). I have not personally used one of these but if I can locate a used one, I'll send it your way.

How about some disk information. There is always debates on some sprung hubs failing more than others and the use of soild disks versus sprung disks. This too would be some good information.

Would it be possible to get some photos of the Action clutch construction? I'll go out on a limb here and say that many of us do not know alot about Action clutches. Some photos would be very cool.

Again, nice job Rocket


[Modified by SLPR, 5:43 AM 6/25/2002]

[CivicNewbie]

[Master of the Universe]

really...damn wish I knew that.... I got their Dual Friction Clutch for 400 bucks canadian after tax....how much power is this clutch gonna hold?

Dual friction means one side of the disc has a full face organic and the other side has segmented organic lining painted orange.

[Master of the Universe]

I've taken some pictures of construction of a Action Clutch. The next post will address discs (sprung vs. unsprung) and different friction materials.

[rice4life]

i had centerforce pressure plate and 3 puck ceramic disk for my last setup and it worked great. the cluth pedal fells a lot heavier at high rpm. when i first had the clutch, i missed shift a lot because i didn't press the pedal hard enought when shifting at high rpm. i have CM stage3 with 7.5 lb. flywheel now.

[Muad'Dib]

Great Post, Rocket. Bizzump for ya!! you should copy this thread and put it on the tech forum as well.

[Master of the Universe]

Just post a link to it. So it's not double posted.

[paulzy]

so how much are we looking at for one of these clutches?

[lucas569]

Rocket whats your take on the negative effects these pressure plates have on the master/slave cylinders? ive seen more than a few wear prematurely when using a pp such as the ACT extreme pp.....

[Master of the Universe]

I haven't seen any problems with dual diaphram pressure plates or ACT Extreme blowing out any clutch master cylinders.

Honda clutch master cylinders and their brake master cylinder are known to go bad. I think they go bad from cycles of use and not so much pressure. My clutch master cylinder went flat on me in my stock GSR.

[lucas569]

thanks, u have IM

[Master of the Universe]

CLUTCH 101...continued

What's the Best Disc?

The answer is which ever one will work properly for your application at the right price.

Here is the best stock disc. It's a Exedy "Unity" disc and incorporates some nice features like forged spring retaining plate(purple) and decently strong springs.




Here is an aftermarket sprung six puck. This particular disc is used by Action, Hersons, Clutch Specialties, and RPS(from what I can see from the pics of there website).

If you compare the features of this disc with the Exedy you'll notice it's held together with 6 rivets rather than the 4 that hold the Exedy together. Also notice that the springs are much shorter .



Here's an aftermarket full face sprung disc with kevlar facing. The kevlar lining will literally last forever. I am not exagerating here. We have many customers coming back to fix their clutches but the kevlar lining just needs to be sand blasted after that there's no way to even tell that it's been used.

Kevlar is also so easy on the flywheel and pressure plates that you can still see the machining marks on the friction surfaces of the flywheel and pressure plates after years of use.

Note the same heavy duty construction as the sprun six puck.



I need to stop here because my computer is about to crash.

To be continued again...


[Modified by Rocket, 10:54 AM 8/24/2002]

[Ray]

so how does copper compare to kevlar?
also, sprung hub vs. solid hub?



[Modified by Ray, 10:32 AM 6/26/2002]

[Master of the Universe]

CLUTCH 101 ...continued

Here is an aftermarket solid six puck used by Action, Clutch Specialties, and Hersons. This is what I consider the standard of disc and works really well in performance applications since it is light and will be easy on your tranny when it comes to shifting. With the Miba friction pads it's also possible to engage chatter free but engagement will be much faster than stock organic.




Here is the baddest of the bad dogs. It's commonly called the "Iron Disc" and is made by Raybestos and used in truck applications and also used in twin disc apps on Ram Clutches in NHRA Pro-Stock cars. This is used in Clutchmasters, Action's and Hersons most heavy duty clutches. This disc needs alot of pressue to work properly since it's a full face and has a lot of surface area.



[Modified by Rocket, 10:54 AM 6/26/2002]


[Modified by Rocket, 10:56 AM 8/24/2002]

[Master of the Universe]

CLUTCH 101...continued

FRICTION MATERIALS

ORGANIC

This is the most common stock lining and is fine for normal driving but should never be used in performance applications. Organic lining is basically wood(cellulose) with a polymer binder and some metallic strands. I am not saying it won't work but it won't last to long if you dump the clutch on high rpm launches. My favorite term for organic lining is cookie dough. And it doesn't matter if you have a heavy pressure plate working on it, organic is still weak.

Here's a pic of a new organic replacement lining.



Here's a pic of a used glazed organic lining. I broke this piece by hand to show that it is fairly weak and that it's composed of fiber.




...to be continued.


[Modified by Rocket, 10:58 AM 8/24/2002]