Clutch recommendation: C1

[Rick C.]

Through my searches of the archives I see many posting regarding C1 clutches. I apologize for posting what seems to be a question that's been answered in many ways, but I'm still not clear regarding which direction to proceed...

Here's what I have:
C1 1960; Stock 283 (1964 era); Muncie 4 speed (1964 era); 10 spline/10 in clutch.

My issue: The current clutch is a "heavy duty" clutch. It's not necessary for my application and it's tough on the leg with the local driving that I do. Thus it's not as fun to drive.

What I'd like to have: A clutch that allows for easier effort when pressing and holding the clutch pedal. The car is driven primarily in town, non-aggressive driving, with frequent stops/starts.

I've talked with the local shops, Jegs, Summit Racing, Corvette supply shops, and have received many different recommendations and am still confused.

As always, I appreciate any advice and insight you folks might have.

Thanks, Rick Coleman (9009)

[Bob B.]

Re: Clutch recommendation: C1

Rick,

I guess my question would be if you have the clutch assist spring installed? This is to help the leg out. If not, install one. When a light-duty clutch is used, the spring has so much assist that the pedal stays on the floorboard, so you can't really use it in that case.

Good luck!

Bob

[Dennis A.]

Re: Clutch recommendation: C1

Rick...
To make life simple...the Paragon multi-finger is a good one for your stock 283/muncie combination. Remove the godzilla spring will help reduce the pressure and may be necessary with the multi-finger set-up.

[Christopher R.]

Re: Clutch recommendation: C1

Look at the LuK RepSets. I believe that's what Paragon sells. That's what I have, and they work great.

Not sure which one your car takes. 1960 Corvettes took one kind (04-084). 1964 283s took another kind.

Dialaclutch.com will probably have the best price. Try to buy it locally in case you need to return it. Shipping is expensive. These things are heavy. I believe Pep Boys carries LuK.

[John H.]

Re: Clutch recommendation: C1

I've used several of the LuK "RepSet" bent-finger diaphragm clutches Paragon sells in C1's with excellent results - low pedal pressure, smooth engagement, no hassles.

[Rick C.]

Re: Clutch recommendation: C1

Ok. Now I know a lot more than I did before. Allow me a couple more questions for clarification:

o I'm confused from two of the posts:
- Bob's post: "...you have the clutch assist spring installed? This is to help the leg out. If not, install one. When a light-duty clutch is used, the spring has so much assist that the pedal stays on the floorboard, so you can't really use it in that case" This makes sense to me, and yes I have the clutch assist spring installed. So it makes sense that it would not be needed with a light-duty clutch.
- Dennis' post: "the Paragon multi-finger is a good one for your stock 283/muncie combination. Remove the godzilla spring will help reduce the pressure and may be necessary with the multi-finger set-up." This seems to imply that removing the spring will reduce the effort required to dis-engage the clutch. It may be because I'm not clear on a "light duty" vs. a multi-finger.

So now...
o The clutch I currently have is a multi-finger. I see that Paragon and dialaclutch have a "three finger" clutch, and a "multi-finger" clutch. Am I correct in assuming that:
- A three finger clutch will require less effort, and will probably NOT require the assist spring?

Or am I making this more difficult than it should be? Of course if I choose wrong I'll just get another chance to practice my transmission/bellhousing/clutch removal skills.

Rick

[Rod K.]

Re: Clutch recommendation: C1

Ok. Now I know a lot more than I did before. Allow me a couple more questions for clarification:

o I'm confused from two of the posts:
- Bob's post: "...you have the clutch assist spring installed? This is to help the leg out. If not, install one. When a light-duty clutch is used, the spring has so much assist that the pedal stays on the floorboard, so you can't really use it in that case" This makes sense to me, and yes I have the clutch assist spring installed. So it makes sense that it would not be needed with a light-duty clutch.
- Dennis' post: "the Paragon multi-finger is a good one for your stock 283/muncie combination. Remove the godzilla spring will help reduce the pressure and may be necessary with the multi-finger set-up." This seems to imply that removing the spring will reduce the effort required to dis-engage the clutch. It may be because I'm not clear on a "light duty" vs. a multi-finger.

So now...
o The clutch I currently have is a multi-finger. I see that Paragon and dialaclutch have a "three finger" clutch, and a "multi-finger" clutch. Am I correct in assuming that:
- A three finger clutch will require less effort, and will probably NOT require the assist spring?

Or am I making this more difficult than it should be? Of course if I choose wrong I'll just get another chance to practice my transmission/bellhousing/clutch removal skills.

Rick

Maybe I'm jumping in here out of turn, but let me see if I can clarify this somewhat for you.

There are, to my knowledge, two basic types of clutches used. One uses 9-12 coil springs in the pressure plate to apply the clamping force to the clutch disc and is known variously as a "three finger" or "Borg & Beck" type. (There's also a "Long" style of this design, but not used by GM that I know of.)

The second type, the "multi-finger" or "diaphragm" design uses a large belleville spring washer about the OD of the clutch disc to apply pressure. Picture a large flat washer formed into a shallow conical shape having radial slots cut from the inner hole dia partially towards the OD forming the multiple "fingers". The OD of the belleville rests against the pressure plate and the inner dia/"fingers" are pushed on by the throwout bearing.

Probably the main difference in operating force required comes from the fact that as the coil springs are compressed to release the clutch with the so-called three finger design, you are compressing the springs linearly causing the pedal force to increase. Hence the need for an assist spring on the pedal under the dash which goes "over center" shortly into the pedal travel adding to your leg force to compress all those 9-12 coil springs in the pressure plate. When the pedal is fully "out", this spring's force is pulling the pedal "out", as you push the pedal in past a point early in the travel, it switches to pulling the pedal "in".

Conversely, with the "multi-fingered/diaphragm" type of clutch, as you push the pedal down, the big belleville spring flattens out which reduces its force and no additional assist is required. The problem with this type of clutch is that, if driven too far (mis-adjusted) it can go "over center" and "stick" at high RPM's, at least the older ones would. Shouldn't be a problem if properly set up in a street car.

The "multi-fingered" clutches mentioned by John have variations which centrifugally increase the clamping force at higher RPM and make them more suitable for higher performance applications, but they're still user friendly in everyday use.

"A three finger clutch will require less effort, and will probably NOT require the assist spring?" Just the opposite. The three finger clutch will probably require more effort and require the assit spring, while the multi-fingered would require less effort, even without the assist spring, and as mentioned, leaving that spring in place probably would prove to be detrimental.

[Bruce B.]

Re: Clutch recommendation: C1

A 3 finger clutch such as the Borg & Beck clutches used in early Corvettes required lots of leg pressure to disengage. The multi finger or diaphragm clutches (these have many narrow fingers) require less pressure and engage nicely. I believe the big spring should be used on both types.
I have thad a diaphragm clutch in my 62 340HP for many years and it works perfectly.
Bruce B.

[Rick C.]

Re: Clutch recommendation: C1

Perfect! Now I've got it. Thanks to everyone for such quick responses.