Anyone running a McLeod 600 series clutch disc?

[A98Coupe]

Just bought a McLeod 600 series clutch disc, McLeod long style PP and McLeod aluminium flywheel to mate up with my new 468 Shelby FE stroker (595 FWHP @ 5700rpm & 586 lb-ft torque @ 4800rpm) and 1-3/8 input 4 speed toploader. Rear end ratio is 3.07.

I chose the 600 series disk (ceramic both sides), because it is rated for up to 600hp, but I've heard that these disks can sometimes give clutch chatter when street driving?

I would be interested to know if anyone else is running this McLeod set-up in a Cobra? Do you experience clutch chatter?

[blykins]

It will be a sticky disc and you'll probably notice some chatter with it and the 3.07 gears. I try to avoid the 600 series discs for street driving. I like the sintered materials if I'm going to be around the 550-650 hp rating.

You could have used the 500 series disc and it would have been fine.

[A98Coupe]

Thanks Brent,
The 500 series disk didn't seem the right choice according to McLeod's description - " Perfect for cars with slightly modified motors making up to 500hp". My engine goes above 500hp from 4500rpm onwards. Admittedly, that's WOT condition which is not going to happen very often on the street, but when it does, I didn't like the possibility of the clutch slipping providing the GY BBs can cope!
You mention sintered disks, but can you recommend one?

[blykins]

It depends a lot on the pressure plate so you can't always go by the description. A 500 series disc would work just fine with your combo.

[RICK LAKE]

A98COUPE There is a couple of things I learned with any clutch and problems
1 Clean engagement, all surfaces have no fluids,dirt, or film on them
2 Break in is very important to get a good gripping surface of both flywheel and pressure plate. 500 miles.
3 Quick in and out of the clutch pedal, NO RIDING it.
4 Air gap clearance between .035"-.050" with clutch pedal pressed in.
5 Clutch pedal stop. The pedal doesn't need to go all the way to the floor. Pedal should have about 1" of free movement before engagement of the slave cylinder. If you have a HTB thats a different story and need the correct clearance to not wearout the bearing permaturally.
6 Racing the car, goto DOT 4 fluid, if not either DOT 3 or fluid designed for hydro clutches
7 Does your disc have a spring hub? This helps absorb shock load to the drivetrain. If not the shock load goes straight to the trans or rearend. Which every the weaker part is will break first.
8 Forget the numbers of what Mcloed is using. This info is for min 3,000-3,500 pound cars. Your car is what 2,500 pounds. The only reason for running a higher pressure plate and solid disc is racing on the track, mostly 1/4 mile and 5000 rpm launches.
9 For 7 years I ran a 452 motor with 368/448 HP/TORK. Ran a 2,400 pound pressure plate and organic disc. No failures or slipping problems. Wear on flywheel was min. I have gone to a 482 motor with 540/620 and this motor is too much for this clutch. I also run a softer tire. Brent sold me a Street twin. It holds my motor, no noise, and should last 10 years of auto cross and road racing on the track. I run GM input shaft trans. May be easier to get clutches for this setup. My flywheel was custom for either Ford or GM pressure plate bolt patterns. Figured if the disc or pressure plate broke, local store would have an 11" clutch in stock to repair at the track and keep running.
10 Last note, until I went to the Twin setup, I wanted the clutch to be the breaking part of the drivetrain. It's the cheapest and easiest to repair. The higher pressure plates and solid discs are not always the best for your driving or cars drive train. Good luck Rick L. PS bigger is not better always except in cubes.

[RET_COP]

Brent and Rick, 500HP/475TQ 351w---McLeod said they would take my Complete Street Pro setup and upgrade it to a Super Street Pro for a fraction of the cost of a new clutch kit. --- Yes?

[blykins]

It depends on how much they want. Is your stuff new? How many miles are on it? The difference between a Street Pro and a Super Street is the disc. If your pressure plate and bearing are new, a new disc will get you there.

[RET_COP]

7000 on the setup. I have to switch to a 26 spline disc so it has to come apart. I thought they upgraded the PP: but you say no. So if its just the disc I can resurface the flywheel and PP myself and just order a disc?

[blykins]

Yes sir. You would go from a 100 series disc to a 500 series.

[RET_COP]

Good info , thanks Brent. I think the 500 series will be a good move for me. According to the chart, the 26 spline only come in 1 1/8 spline length and under Ford there are no 26 spline. I'll just have to see what type of Diaphragm PP I have before I make any moves.

[blykins]

1-1/8x26 is what you need.

[RET_COP]

10-4

[A98Coupe]

Thanks Brent & Rick for your advice, but I think I need to explain the full story here to explain my predicament and ask your opinion one more time before I go wasting more money on alternative clutch parts.

My engine builder originally spec'd a McLeod Super Street Pro clutch assembly Part No. 75235 (500 series disk - ceramic FW side - organic PP side, 12" diaphragm PP, 1-3/8" x 10 input spline). I questioned this clutch for my engine because McLeod's website said it was good for up to 500hp. My engine builder went back to his contact at McLeod and came up with the following:

600 series ceramic disk (FW side & PP side), Sprung centre, Part. no 260663 (12" dia. big input)
Long style PP Part No. 360650 (2000 lb clamp load)

The guy at McLeod said this set up would give better release characteristics at high rpm.

The question now is if you think the 600 series disk is going to give me chatter problems, then if I buy a 500 series disk, will my long style PP have enough clamp load to prevent slipping? The equivalent diaphrapm PP Part No. 360821 has 2250 lbs clamp load. I can't help thinking I should have stuck with the original Super Stock Pro clutch?
What do you think?
Thanks
Stuart

[blykins]

With your rearend, I would expect it to chatter.

Clutch capacity is a function of car weight, tires, the pressure plate, disc, and the diameters of each.

[blykins]

Allow me to hop on a soap box for a second. Lots of guys want 600-700 hp but they are not willing to put up with it or buy the parts to support it. If you want something that is over capable of handling the power without chatter, you need a twin disc. If you want a single disc, you will most likely run into some chatter with the ceramic and sintered iron discs because of your rearend ratio. If you want a single disc clutch and no chatter, you don't really have a choice. A 500 series disc will most likely work just fine. But the instant you bolt on a real sticky tire and start driving aggressively, you will approach the limits.

A 600 series disc isn't cheap. At your level, I'd pay the $700 for a twin disc.

[RICK LAKE]

A98COUPE Stuart You have not said what you are going to do with he car, Road race, auto cross, car shows, cruising, etc... We also don't know your abuse level to the car, Driving like Miss Daisy, Fireball Roberts, Smokey and the What's his name??
I am not a fan of puck discs to start. I tryed one many years ago when they first came out. Some of the problem was breakin, I did about 100 miles and trashed it. Slipping, chattering, banging the drivetrain with hard engagements when clutch was hot. Broke 4 universals and a couple of trannies and transfercases. This was in a CJ5 jeep. Same weight as a cobra with about 50hp and 60 ft of torque less than 452 motor.
I found that going to a higher pressure plate load hold, and staying with a basic organic disc that was truck applied worked the best. Too much abuse the clutch would slip. Allow to cool off and everything was OK again.
I agree with Brent about a twim disc setup. IT has feedback, slips a little on cold takeoff, but overhaul locks the motor to the drivetrain and holds. I break the tires loose before any clutch slipping. The down side FOR ME ONLY is solid hubs on the discs. I like spring hubs that absorb engagement of power shock to drivetrain, yes it's a small loss of power but saves parts.
If you want to go with a single setup and the gearing you have in the car, I would up the pressure plate to the weight of the car, 2,600 pound and stay with a spring hub disc. Modify your driving to smooth on and off the pedal, and roll into and out of the throttle better than what you are doing. This helped me and made my car happier when racing. It takes time, parts breakage is down, tire wear is better, car is happy and going faster than I want. Still working on the man handling problem of myself on the tracks. Hear it comes with time, not.
Side note we didn't fine out what the 1st gear was in the trans?? I have a 3.08 in a TA and ran a 4 spd for years in all weather. Not riding the clutch and downshifts extended the life of it. Ex wife blew up clutch in 2 weeks of her driving it. I went 4 years.
Last note, would go through 3-5 clutches before having to replace a tranny or rearend of the car. Job may not be easier but is alot cheaper. I am happy with streettwin. Been in car for 3 years. Good breakin and 98% track running.Rick L.

[A98Coupe]

Brent,
Thanks for the advice. I acknowledge that I've made the wrong choice for my car which will probably be 60% normal street driving, 35% agressive street driving & 5% competition. I also acknowledge that the 500 series disk is better, but I wanted to know if I have to change my PP from the current 2000 lb long style to the 2250 lb diaphragm type. I think Rick L. has answered that for me.
Rick L.,
Thanks for the advice. I guess I now have a spare 600 series disk & long style PP!

[blykins]

I would not use a diaphragm pressure plate for your application. The Long style pressure plate by nature is counterweighted which helps with the higher rpm clamping force.

If you have a Long style pressure plate, keep it, and change the disc. Been doing this for a long time now and I've never had anyone come back and tell me that their clutch was slipping because of power/traction issues.

[GBowman]

Brent-I love the set up you did for me, it took a little getting used to but now with about 300 miles on the car I like it more and more. And it works well at 7000 too

[A98Coupe]

If you have a Long style pressure plate, keep it, and change the disc. Been doing this for a long time now and I've never had anyone come back and tell me that their clutch was slipping because of power/traction issues.

Thanks Brent,
That's good to know.

Stuart