Which clutch disc do you recommend, and why?

[cleandan]

I'm working on a 289 with a recent Tremec T5 install.
I removed the factory close ratio Borg Warner T10 and installed the T5 so this car can make longer road trips with a bit less rpm going down the highway.

The T10 was running a diaphragm style pressure plate, and what appeared to be a single compound organic clutch disc (10")...basically standard replacement stuff.

The new parts look exactly the same, but carry a different part number and brand name.
Still, it's a diaphragm pressure plate and an organic clutch disc...nothing fancy, but it is labeled as heavy duty.

Seeing as the 289 is a 306HP spec motor there is no great need for anything special and the duty of this car is spirited street driving.

Anyway, this set up, which looks and measures the same as what was removed, has quite a different pedal feel.
The old set up had a linear pedal pressure from released to engaged (floor to foot removed)

The new set up has a peaked, or progressve, pedal feel with a standard amount of pedal weight from released until about 70% depressed, at which point the pedal gets a bit stiffed and then releases for the rest of the travel to the floor with ease....not zero pressure, but cetaintly half of what was there just 1/2" travel before.

My pedal adjustments measure correct.
Released pedal is right around 6.5" from the floor.
The endagement and release points are right where they should be, and the free travel is within spec.....But the pedal feels odd with that release and free travel towards the floor.

I did slip fit the disc prior to install to ensure easy, free travel over the splines, and the splines looked perfect too.

This gives the clutch pedal a pretty touchy area of grab that is making slow, parking lot, garage parking, around the cruise-in area with people everywhere a bit uncertain.

I'm wondering if I damaged the clutch disc somehow during install?
Things went well, with a bit of trouble engaging the 10 spline shaft, (took some josteling) otherwise things went together very nicely with no drama at all.

Because I will be taking this apart to inspect, I am wondering if you fine fellows recommend a certain make, brand, style of clutch disc to use for a spirited driver car?

Thanks and have a great day.

[Heo]

I dont know if i understand you but...You get progressiv resistans untill you get over the peak so to say? and ease upp after that?
Sounds like a normal diaphragm cluch to me

[pbf777]

The old set up had a linear pedal pressure from released to engaged (floor to foot removed)

     Now, this from the perspective of one not being there, looking at, or holding anything in hand but,  this would seem to represent an older style, "stock" or "O.E.M. spec."   (perhaps not actually Ford O.E.M. of coarse) replacement unit.

The new set up has a peaked, or progressve, pedal feel with a standard amount of pedal weight from released until about 70% depressed, at which point the pedal gets a bit stiffed and then releases for the rest of the travel to the floor with ease....not zero pressure, but cetaintly half of what was there just 1/2" travel before.

This gives the clutch pedal a pretty touchy area of grab that is making slow, parking lot, garage parking, around the cruise-in area with people everywhere a bit uncertain.

     And this effect seems to be representative of most of the aftermarket "Heavy-Duty" or performance brand diaphragm clutches, this caused by the difference being the diaphragm spring plate and it's resultant increased clamp-load intention coupled with a different fork-finger leverage ratio required for driver "feel" acceptability, but unfortunately just often not perfectly matched particularly to the mechanical linkage systems otherwise engineered for "long-style" clutches, so in the end one often ends up with this funky function!   

    And this is why I don't like to recommend "diaphragm" clutches in the applications that originally were of the "long-style" or "3-Finger" type.   

    B.T.W. your utilizing a "10-inch" clutch?  Note that Ford moved to the 10-1/2" units even on the S.B.F.'s pretty quickly as the power climbed in the '60's and although Ford revisited the 10-inch in the earlier FOX Mustangs they again stepped-up to the 10-1/2-inch units (now 11-inch) pretty quickly as the trend to run'em hard came about.   

    Scott.

[cleandan]

Thanks for the replys.
I guess if this is how the HD diaphragm pressure plate acts then all is likely good to go.
I just have to adapt to the new set up.

Things work well from a mechanical standpoint, its just odd compared to what was removed.
A diaphragm pressure plate was removed but I suspect it was "standard" issue, nothing HD about it, because it did have a pretty light pedal feel to me, but it worked fine enough.

[Rory428]

What model vehicle are we dealing with here? I am not a fan of diaphragm clutches on older Fords that left the factory with a Long style clutch, especially so called "performance" diaphragm  clutches. That said, I did use a Dynapack stock replacement clutch for a late 80s 5.0 FOX Mustang in my 78 Fairmont with a warmed over 302 and T5, that worked fine, even launching on slicks at the dragstrip, running high 12s.If it was me, spending MY money, I would install a Long style McLeod "Street Pro" clutch for normal driving, but if any dragstrip action, especially with slicks were in the possible future, I would get a McLeod 'super Street Pro, preferably a 10 1/2" version. The pedal height and travel "specs" are for use with a factory Long style clutch, and may be very different than what a diaphragm clutch may want. I can say that I have typically found that a diaphragm clutch , in a Long style clutch style vehicle, usually takes more pedal travel compared to the Long. Likely due to a slower lever ratio of the pressure plate .

[cleandan]

What model vehicle are we dealing with here? I am not a fan of diaphragm clutches on older Fords that left the factory with a Long style clutch, especially so called "performance" diaphragm  clutches. That said, I did use a Dynapack stock replacement clutch for a late 80s 5.0 FOX Mustang in my 78 Fairmont with a warmed over 302 and T5, that worked fine, even launching on slicks at the dragstrip, running high 12s.If it was me, spending MY money, I would install a Long style McLeod "Street Pro" clutch for normal driving, but if any dragstrip action, especially with slicks were in the possible future, I would get a McLeod 'super Street Pro, preferably a 10 1/2" version. The pedal height and travel "specs" are for use with a factory Long style clutch, and may be very different than what a diaphragm clutch may want. I can say that I have typically found that a diaphragm clutch , in a Long style clutch style vehicle, usually takes more pedal travel compared to the Long. Likely due to a slower lever ratio of the pressure plate .

Thanks Rory428.
This is a 1965 Shelby GT350 that has been modified to give better long road trip driving.
Originally it was equipped with a 10", long style, clutch. A 4-spd, close ratio, Borg Warner T10 transmission, and a 28 spline Detroit Locker wearing 3.89:1 gears.
This set up produced 3200+ rpm driving at todays highway speeds.....which is okay for cruising around town too and from shows and cruise-ins.

The owner wants to take this car on road trips and guided cruises like the Copper State 1000.

After doing some math using tire diameters, rear end gear ratios, and transmission ratios I settled on a combo that seemed to work pretty well on paper.
215/70/15 tires, 3.70:1 rear end gear, and a Tremec T5 with a .72 O/D ratio.

The "kit" was purchased through Modern Driveline and everything has gone really well with the only real hurtle being the shifter adaptor needing modifications to fit the factory shift boot.

The clutch disc they supplied is what they call their "House Brand"...which is made in Korea (not happy with that) and is supposed to be a dual friction, heavy duty, style disc. It is a 10" diameter, riveted lining, full circumference type that appears stock.

The pressure plate is a diaphragm style that also appears stock but the fingers are a bit stiffer than what was removed.

I purchased all this as a "kit" (they don't actually have a kit but you can order each needed part) as a means to and end for the total package modification.

I think they have done a good job putting this stuff together, but I do wish they had some other offerings for the clutch disc and pressure plate.

I currently have the McLeod stuff you mentioned on my shelf awaiting install in my Sunbeam Tiger so I could put it in this Mustang to give it a try.....but I'm not enthusiastic about taking it all apart again just to try.

So far things are working fine, after modifiying the shift levers to not bind against the boot edge preventing gear engagement, as well as cutting the boot upon first shift attempt into second gear....that's gotta be replaced dag nabbit! Which includes pulling the seats and carpet in order to mount the shift boot properly....dag nabbit!

Anyway, I have driven on a few diaphragm clutches and they just have not had this odd pedal feel so I asked here to see what I can learn.

Thanks for your input and parts suggestions.
I appreciate the time and effort.

If things will be swapped I will likely get those parts for the swap.

For now I am just approaching 300 miles on the break in so maybe things will get better after 1,000 miles or so.

[Chuck]

The over center spring comes to mind. To the ones who have switched from the long style plates, how many have removed the spring?

[cleandan]

The over center spring comes to mind. To the ones who have switched from the long style plates, how many have removed the spring?

So far I have not had any issues with the overcenter clutch pedal.
Some say it will stick the pedal to the floor when high rpm shifting.
Nothing like this has happened yet, and the helper spring is still in place.

[pbf777]

The "kit" was purchased through Modern Driveline..................The clutch disc they supplied is what they call their "House Brand"...which is made in Korea (not happy with that) and is supposed to be a dual friction, heavy duty, style disc. It is a 10" diameter, riveted lining, full circumference type that appears stock.

    So just out of curiosity, how did you end up with a 10" clutch, as I'm not aware of these being standard in any "kit", nor appreciated if avoidable   

Anyway, I have driven on a few diaphragm clutches and they just have not had this odd pedal feel so I asked here to see what I can learn.

    I'm thinking due to choice of the 10" application unit and as it is presenting less surface area and reduced leverage capacity than that of say the 10-1/2" units, a greater clamping-load spring was deemed required in order to provide an equivalent drive load carrying capacity, and hence the resultant odd functioning effect, this as described previously as not being so uncommon a result.  And I find it rather odd to have specified this type (10") unit in anything but that which would not accept a larger unit and if your utilizing a 157 tooth flywheel (and hopefully not the O.E.M. production cast iron unit?) then why not the 10-1/2" examples, also which present a far greater sum of choices?   

    Scott.




     

[cleandan]

Today I replaced the odd feeling diaphragm pressure plate and clutch disc.

In went a McLeod 10.5" Street Pro (long style) pressure plate and clutch disc.
The throw out bearing was different, with a wider face on the McLeod unit....and a effing grease zerk that literally broke off when I tried to use it.....GRRRRRRRRR!

But otherwise things went in just fine.

With no other alterations or adjustments the McLeod clutch has a linear pedal weight and engagement feel.
This clutch does have a heavier pedal....and a bit of chatter (But I only have about 30 miles on it so far) otherwise it is way, way better to drive than the other clutch.

We will see how it is doing after 500 miles of stop and go break-in as described in the directions.
I'm optimistic because of how much better it is already.