clutch set-up

[dcs155]

Hi, I have a classic roadsters cobra I built in 1997 and would like input on a better clutch set-up. The car has a ford 460 and tremec 3550 trans. The clutch pedel preesure is so hard that over the course of the last 12 years of driving the car I have bent three of the rods that run from the pedal to the master cylinder. I remedied that by making a new rod out of a 1/4 socket extension. I have tried three different tilton master clyinders with bores from 1/2" to 3/4" and still the same extreme pressure. next it pushed the bolts wich hold the master cylinder thru the fiberglass firewall, Obviously something is not right.

I am using a tilton hydraulic thro-out bearing and a 11" center force clutch with a diaphram style pressure plate.

Any help would be greatly appreciated!!!! Thanks, Dave

What would be a better set-up to use in my car?????

[dcs155]

I just checked my other master cylinders and the bores were 5/8", 3/4", and 7/8" not the sizes previously stated.

[Larry Spillman]

Originally Posted by dcs155

Hi, I have a classic roadsters cobra I built in 1997 and would like input on a better clutch set-up. The car has a ford 460 and tremec 3550 trans. The clutch pedel preesure is so hard that over the course of the last 12 years of driving the car I have bent three of the rods that run from the pedal to the master cylinder. I remedied that by making a new rod out of a 1/4 socket extension. I have tried three different tilton master clyinders with bores from 1/2" to 3/4" and still the same extreme pressure. next it pushed the bolts wich hold the master cylinder thru the fiberglass firewall, Obviously something is not right.

I am using a tilton hydraulic thro-out bearing and a 11" center force clutch with a diaphram style pressure plate.

Any help would be greatly appreciated!!!! Thanks, Dave

What would be a better set-up to use in my car?????

Your clutch must be a racing clutch on the street, What I have done is convert to a smaller master as that will give you more applied pressure at throwout bearing than a big master. The other thing that works is convert to a pusher throw out instead of a tilton puller,This solves a lot of problems and is smooth to operate. Contact me if you have any more problems. I mount the pusher on the side of the bell housing and alignment must be close or you will get too buch wasted motion from slave cyl.

[Tim Brewer]

I have basically the same setup as you, and yes, my pedal is quite stiff but I've never bent or broke anything. Larry is right about M/C sizes, it's oppisite of what most people think. The maximum ammount of leverage is achieved by going to a smaller bore master, not a larger one. The same applys to the brakes as well.

[dcs155]

I'm starting to think that my clutch was mispackaged as I wanted an 11" and the stock weight but think i recieved the racing clutch instead. I also have a lakewood scattershield not a stock belhousing, can I use that set-up with the lakewood???? I also just checked and I have a Mcleod thro-out bearing if that makes a difference. Thanks for the help!!!!

[Gunner]

It was my first thought that you have "too much clutch." These cars don't need the heavy, high-grip clutches that 3500-4000 pound muscle cars do. A relatively light street clutch (like a Centerforce I) will do fine; if there's slippage needed, it will happen at the rear wheels.

You might just go right to the source of the trouble and put in a proper clutch. Trying to compensate with all new linkage would be almost as expensive and just as much trouble.

[Double Venom]

First question to ask with the pedal pressure 5 to 10 times more than it should be is:
Pedal ratio?
What is the mechanical setup on the pedal to the rod? Is it as designed or has someone changed it?
The pedal should be pushing the rod no lower than 2"s below the hinge point. (I'll get the exact distance tomorrow.)
DV

[dcs155]

Hi Ed, just went out in the garage and as accurately as I can measure it appears from center of the pedal pivot to were the master cylinder rod is on the pedal I'm at 2 1/2" wich is prob not helping matters at all. The push is a nice straight shot with no binding but what is strange is that the first 2-3" of travel there is no resistance and all the pressure and clutch engagement is in the last 1" of total travel. Kinda like a on-off switch

It's been this way since day one and at first thought it was a bleeding issue but its bled properly.

I went thru my original paper work and the clutch disk is a mcleod #260273,pressure plate is a mcleod #360850 and the flywheel is a centerforce #700260. Is it possible that between way to heavy of a clutch and my pivot being off by almost 1/2" that would be causing this??? I really appreciate all the help and info as I'd like to fix this once and for-all. Dave

[Double Venom]

Dam,
I'm sorry, I start working at 5AM or earlier and some stuff-0K, a lot of stuff slips my mind these days...

The pivot point is: From "inside" top of the firewall to the pivot pin of the clutch pedal is
" 2-1/4"s " Any more than this will create an unbelievable amount of pressure to release the clutch! (The clutch rod goes through the firewall at 1-1/4" from the top of the firewall.)

If this is as it should be the something is wrong with your set up-even a "racing"-dual clutch diaphragm should not be as hard as you describe!

[RICK LAKE]

dsc155 Dave if this clutch has floating weights? This is the main problem for this clutch. If you want to do a test, pull the car apart down to the pressure plate and remove the ring and floating weights on the pressure plate, reassembly the car and go road test. tell me how the clutch works now. I am not going to say any thing to chnage your answer. If you can get the trans out you should have enought room to remove the weights and steel ring. Give us a reply after this is done, I will then tell you.......more info. Rick L. Ps been there, done that, Dave sent me a private e-mail with your number to reach you at in the evening.

[patrickt]

Originally Posted by RICK LAKE

dsc155 Dave if this clutch has floating weights? This is the main problem for this clutch.

Rick, the McLeod #360850 doesn't have the little weights on the fingers, you're thinking Centerforce.

[dcs155]

Thanks again for all the help !! I'm gonna get the car into a friends shop and up on a hoist in a week or two. The idea of the trans, bellhousing and clutch removal on jackstands in my garage doesn't sound like much fun! I'll get some pics of the teardown, see what the problem was and keep you guys informed on the outcome. My wife is actually getting excited about ( maybe ) being able to drive the car (i think she thought that the heavy pedal pressure was my way of not letting her drive) Dave

[blykins]

What is the part number of the throw out bearing?

[CobraEd]

Fix it immediately and simpley, . . . . . use a cable.


.

[blykins]

My opinion is that he's got other issues that switching to a cable won't fix. Usually if pedal pressure is high on a hydraulic clutch, you can get away with going to a 3/4" cylinder....if he's tried that and a 1/2" too and the pedal is still unbearable, something else is binding up.

Clutch disc isn't in backwards is it?

[RICK LAKE]

dcs155 Dave your first post was a centerforce assembly and I went with that alone. Now you have a centerforce flywheel and a Mcleod clutch assembly with a tilton throwout bearing. Couple of picture would really help. With your new info, here are a couple of things that need to be checked
#1 Explain about your lakewood bell housing, is it stock or modifiled?
#2 Make sure that the bell housing is centered on the block.
#3 It sound like it's possible that there is a missing spacer on your throwout bearing assembly. There is a setup measurement for the correct clearance before the bearing face touches the clutch fingers. Lets get the BASICS checked and done first before swapping any parts like master cylinders.
#4 call centerforce and see if there is a measurement for the correct depth of the disc in the flywheel. If the disc in the flywheel is too thin you will have engagement problems and all kinds of fun. Is you flywheel rebuildable?? If so send it back and have it done.
#5 Is if Brent know about any spacer for your setup? Some do, some don't.
#6 If you are bending rods from the pedal to the master cylinder of the clutch, there is an alignment problem also. There should be a double steel plate on each side of the body with the fire wall in between the 2 plates. The plates need to be about 6x6 inch square to spread out the pressure of the clutch being used.
#7 As far as pressure plates, your car weight is about 2,600 pounds and the HP and torque on the motor are around 500/550. You need a pressure plate with a 2,800 pound setting. The disc depends on your driving and how much you slip the clutch when driving.
#8 you might want to work on the car in your garage because this could be a 2-3 day job if you have to get parts. Centering the bell housing will take a good hour if you are lucky alone. Mine took 2 1/2 hours to get under .003" all the way around. You might want to buy allen head bolts for the bellhousing to the motor for easier work.
Before you pull it apart shot some pictures please. Rick L. Ps sorry about not reading the WHOLE thread and just skipping to without reading second thread. Rick

[Double Venom]

Gentlemen, I'm betting his pinion point on his pedal is too low Period. "I" built a particular Cobra years ago and have used about every clutch mentioned, including the ones with the little weights (Gad-what a problem they were!)

It was a 460, McLeod clutch and throwout bering. Since the car was first engineered it was never made ready for "Hydraulics". I swear it took two men and two girlfriends to push that clutch in. I too had to get a Hardened shaft to keep from bending the rod. I called McLeod a couple of times raising hell about there clutch and throw out bearing only to find out my pivot point was about thee inches low! Re-engineered the pivot assembly to raise it higher on the clutch pedal and the problem was fixed. (I think Mr. Higgins got me straight on this problem.)