eleven (11") clutch..Q

hardtimes

hardtimes

Well-known member
I just purchased a 49 merc engine. It has an eleven inch clutch/pressure plate/housing. A buddy said that this 11" is tooo much clutch,in his opinion, for an AV8. What's your experience/knowledge here..is it too much what? FYI- came out of a duece 11/2ton.
 
Yes, it is too much clutch for an AV8. You'll develop one leg with twice the muscles of the other and walk lopsided! :D:D
A 9" will be fine.
 
I have a 49 mercury. with a cracked block Lots of good parts. it came with the 11" I have a 52 ford that came with the 9" the bolt pattern is different. the 9" will not bolt up to the 11" flywheel.
 
Using a pressure plate that's significantly larger than the clutch disc, I'm wondering if it would be wise to remove a few springs from the pressure plate. I have a situation of a pressure plate in hand (no cost) and a flywheel drilled for it (also no cost.)
 
I had a 34 p.u. in the 60's it had an 11" behind a sbc and in front of 39 zepher ******.

Worked fine, just rev it and it would shove your foot up and go.

marvin
 
even with three of the pressure plate springs removed the 11" is tooo much.The fly wheel can be redrilled and tapped for the 9"
 
I've run an 11 inch clutch on my 50 Ford w/FR flattie for five years and no problems. I don't find it to be too hard to push in for my 71 year old leg and have been in some heavy traffic for several hours.
 
my only objection to the 11" clutch is that it weighs a LOT... I don't need that on my engine... I run a 10", would be ok with a 9" or a 9 1/2" (from 49-53)... Karl
 
flathead4rd said:
I've run an 11 inch clutch on my 50 Ford w/FR flattie for five years and no problems. I don't find it to be too hard to push in for my 71 year old leg and have been in some heavy traffic for several hours.
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Hmm, 71! Good testimonial. Keep truckin young man...I'm right behind and catching up quick! Yeah, I love those shoe boxes and back when..had my share. lol
 
All diameters work of course but my vote is for bigger is better.
11" friction surface works for me in my 29 roadster and 32 5W.
If your legs are too weak to operate a clutch, consider a C4 automatic.
Hydraulic activation is also an option, or change mechanical advantage ratio
of clutch linkage for easier pushing.
Pressure plate spring rate can be more a factor of stiffness than disc diameter.
 
Here is my 2 cent worth. I don't use the 11 in. in any street car because it's way heavier that necessary. Most of us try to put a little more performance in these engines. Why put in a heavy clutch and pressure plate which robs hp when a lighter 9in. will work fine unless your hawling 10 yard of gravel. I just had an 11in. wheel redrilled and balanced for a 9in. setup, V8 going in a Model A pickup. Walt
 
Karl Wolf said:
my only objection to the 11" clutch is that it weighs a LOT... I don't need that on my engine... I run a 10", would be ok with a 9" or a 9 1/2" (from 49-53)... Karl
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Karl,
Weight is worth considering, my unskilled self tells me. How about an aluminum flywheel as a consideration..if I step down to say, 9"? Or is that looking at trouble?
 
FWIW early 60's, 32 5w with 55 olds, 39 tran, 11" truck p/plate, 10.5" disc but was using hydraulic clutch not mechanical linkage
Paul in CT
 
if your runing a 378 or 354 rear & there are hills in your airea i would go with a 10" ford did i think the last year of the 9 was 1940
 
Aluminum flywheel is too light for a street driven engine, (other peoples opinions that I respect) ... Karl
 
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