Diaphragm Clutch

Richard in Anaheim CA

Richard in Anaheim CA

Well-known member
On lightened flywheels and V8 Clutch conversions, diaphragm pressure plates and clutch discs are becoming popular.

I would like to know what vehicle the clutch comes out of and the comparative advantages and disadvantages of this setup over the more conventional "long clutch" from early Ford V8

Thanks

Richard
Anaheim CA
 
Richard,


If you decide to use the diaphragm clutch, the fingers at the center must be machine shortened, otherwise they will not clear the throw out bearing. You can use the same clutch disc as used with the V8 and A . Also, the flywheel must be drilled and tapped for the diaphragm or V8 pressure plate. Also the diaphragm clutch is much lower profile than the V8.


I am sure you know the above information but thought it would not hurt to list again.


Here in Quincy we are lucky that one of our members has a nice complete shop set up at he residence and does any machine work we may need.


Ron
 
Clutch Masters in Rialto, I've heard, stocks a lightened wheel and diaphragm clutch. I believe it uses a Ford Ranger pickup clutch cover.
 
I have a diaphragm clutch in my car, unfortunately I don't know what it's off as the clutch man who happened to own a Model A said this will do and also provided a modern throw-out bearing to suit which fitted the Model A. All very simple and a nice light & smooth clutch
 
I have a diaphragm clutch plate in my pickup. It came with the lightened flywheel I bought from Ron Kelley.
 

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  • Pressure Plate Sachs BBC1904.jpg
    Pressure Plate Sachs BBC1904.jpg
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Richard in Anaheim CA said:
Thanks guys.

I can always depend on Fordbarn when my brain takes a vacation
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Hey Richard,
I have installed a new diaphragm pressure plate on my new B rebuild. It is 9", and I got the model / part # from CarlG here. As Carl says, his came on his engine from the rebuilder. I think that I have the part # somewhere, if you think that that would be of any help, I'll look for it ?


I've been using the B on a stand as a test mule. The parts (pressure plate/disc and flywheel) was balanced out as a unit. It runs out very smooth !


BTW...I don't know anything about the comment that you must do some mod to the clutch fingers. I have tried a new throw out bearing on the model pressure plate that I used and I can't see a problem.
 
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The only shortcoming of that clutch is, when the Diaphragm decides to crack, it slips INSTANTLY!!! And "hopefully" COASTS HOME!
Bill Veryoldclutchrebuilder
 
"BTW...I don't know anything about the comment that you must do some mod to the clutch fingers."

The fingers on the pp "grow" inward as the clutch is depressed. Note the groove cut. There's no apparent interference ... until the cutch is depressed ... then clutch pedal hangs up. Any need for modification would depend on the pp selected.

throwoutdisphragm.jpg
 
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BILL WILLIAMSON said:
The only shortcoming of that clutch is, when the Diaphragm decides to crack, it slips INSTANTLY!!! And "hopefully" COASTS HOME!
Bill Veryoldclutchrebuilder
Click to expand...

That sounds odd compared to my experience, I had a diaphragm clutch in a 1980 F-150 that cracked and then wouldn't release.
 
Hoop said:
"BTW...I don't know anything about the comment that you must do some mod to the clutch fingers."

The fingers on the pp "grow" inward as the clutch is depressed. Note the groove cut. There's no apparent interference ... until the cutch is depressed ... then clutch pedal hangs up. Any need for modification would depend on the pp selected.

View attachment 354665
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Hey Hoop,
I see what you're saying.
I think that's why the pp that I have on the spare engine is working, as it was researched by an engine builder and found to not have to be altered. Thanks for the picture, it looks different from my pp.


Also, I've often heard some say that you need to use a 'special' throw-out bearing when using diaphragm pp. Again, my new bearing fits pp very well. My guess is that the 'fingers' , is shaped differently , may require a different bearing ? But, how to know what bearing ??
 
When I changed my Corvette from 3 finger to diaphragm type the throwout bearing had to be changed from flat faced to curved face as the multiy fingers of the diaphragm clutch change angle as the bearing is pressed in to it.
 
hardtimes said:
Hey Richard,
I have installed a new diaphragm pressure plate on my new B rebuild. It is 9", and I got the model / part # from CarlG here. As Carl says, his came on his engine from the rebuilder. I think that I have the part # somewhere, if you think that that would be of any help, I'll look for it ? ...
Click to expand...

Picture in post #8 Hover over picture for part # (Sachs BBC1904)
 
CarlG said:
Picture in post #8 Hover over picture for part # (Sachs BBC1904)
Click to expand...

Hey Carl,
Thanks much for that post and information. Yeah, I took your advice/info and have that setup on my new B.
BTW..
hovered of picture just as you advise..nothing.
Wonder if it is just me/my machine here or what.
A short time ago (month or so) something happened. I also can't now put up the little smiley faces, can't post pictures as used to and now can't 'hover'..(smiley face here!).


Always a silver lining, if looked for though. For years, till now, when I looked at several pictures posted by anyone, I had to look at one at a time and go back an then another so forth. NOW, all of a sudden it is back like in the old days...i.e.-, I can now view first picture then just click on 'next' and voila..whoohoo ! What the heck, I'll settle for that. Past bedtime and most likely not making sense.
 
If you use the original flat-faced bearing, it will work but will likely give a funny feel to the clutch and not release as smoothly. The first diaphragm clutch I installed was from a high performance Mustang and the fingers rubbed on the front bearing retainer, at the very front. I merely ground a little off the internal finger diameter and all was well. The second one, from a Ranger pickup was fine as-is.
 
hardtimes said:
Hey Carl,
Thanks much for that post and information. Yeah, I took your advice/info and have that setup on my new B.
BTW..
hovered of picture just as you advise..nothing.
Wonder if it is just me/my machine here or what.
...
Click to expand...

When I first posted that picture, the "hover" worked. 5 minutes later it didn't, so that is why I went back and posted the part number. Go figure!
 
CarlG said:
When I first posted that picture, the "hover" worked. 5 minutes later it didn't, so that is why I went back and posted the part number. Go figure!
Click to expand...



THANKS for that (tooth grin face) !
This time it ain't me and my computer.
 
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