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  •  » I need a clutch dimension...Help!

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    8/05/2013 11:58 AM  #1

    MS
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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,476

    I need a clutch dimension...Help!

    I have a friend with a clutch problem.  He installed a brand new SPEC brand clutch and it slips like crazy, even with the cable completely slacked.  Upon removal for inspection, it appears the pressure plate only clamps the disc by about 0.060".  I do not have the specific dimension, and I have never had the need to check it, but as I recall, when I bolt up a clutch and pressure plate, the bolts have to pull the pressure plate down quite a bit in order to clamp the disc.  Like 3/16" to 1/4", but not sure.  I am thinking he got the wrong clutch disc with his pressure plate, and the disc is too thin to be properly clamped by the pressure plate.

    Does anyone have a clutch disc and pressure plate laying around they could measure?  The distance I need to see is how far the flywheel is away from the pressure plate before the bolts are tightened.  Like if the disc was laying on a table and the pressure plate was sitting loose on top of it, how much distance is there between the table and the pressure plate mounting pads?

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    8/05/2013 2:50 PM  #2

    jerseyjoe
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    Registered: 4/01/2013
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    Re: I need a clutch dimension...Help!

    MustangSteve wrote:

    I have a friend with a clutch problem.  He installed a brand new SPEC brand clutch and it slips like crazy, even with the cable completely slacked.  Upon removal for inspection, it appears the pressure plate only clamps the disc by about 0.060".  I do not have the specific dimension, and I have never had the need to check it, but as I recall, when I bolt up a clutch and pressure plate, the bolts have to pull the pressure plate down quite a bit in order to clamp the disc.  Like 3/16" to 1/4", but not sure.  I am thinking he got the wrong clutch disc with his pressure plate, and the disc is too thin to be properly clamped by the pressure plate.

    Does anyone have a clutch disc and pressure plate laying around they could measure?  The distance I need to see is how far the flywheel is away from the pressure plate before the bolts are tightened.  Like if the disc was laying on a table and the pressure plate was sitting loose on top of it, how much distance is there between the table and the pressure plate mounting pads?

     
    I'll bet the shoulder on the bolts is holding it back from full clamping ???...jj

    Last edited by jerseyjoe (8/05/2013 2:58 PM)

    "Never put a question mark where God put a period "  Richard Petty
     

    8/05/2013 4:48 PM  #3

    MS
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    From: Canyon Lake, Texas
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    Re: I need a clutch dimension...Help!

    I did not see the bolts, but I do not think they are the issue.  I am thinking the disc is too thin.  The pressure plate barely has any preload on it when bolted up.  If no one can supply a dimension, I will go to OReillys tomorrow and look at a stock 5.0 clutch.

    Hopefully someone has a clutch laying around not yet installed and they can measure it.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
       •Thread Starter
     

    8/05/2013 4:49 PM  #4

    KeithP
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    From: Scottsdale, AZ
    Registered: 6/10/2013
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    Re: I need a clutch dimension...Help!

    I threw away my old clutch disc. But I kept the old Borg Warner style pressure plate. I turned the pressure plate upside down and put a straight edge across the mouting holes and measured the distance from the straight edge to the pressure plate disc. It meassured 0.140". If that helps any.

    1966, vert, 347 stroker, T5z, 4 wheel disc, pb, 3.70 LS 9", EPAS
     

    8/05/2013 5:23 PM  #5

    Jerry67Fastback
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    Re: I need a clutch dimension...Help!

    used 11" long style clutch disc measures .305

     

    8/05/2013 5:27 PM  #6

    MS
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    From: Canyon Lake, Texas
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    Re: I need a clutch dimension...Help!

    Jerry67Fastback wrote:

    used 11" long style clutch disc measures .305

     Thanks, Jerry.  Is that the thicknes of the disc itself?  What I really need to know is the recess dimension of the pressure plate.  If you sit the pressure plate flat on a table and measure the distance between the table and the mounting bolt surfaces, then I will have what I need.  The pressure plate friction surface will hold the body of the pp up off the table a bit.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
       •Thread Starter
     

    8/05/2013 6:24 PM  #7

    KeithP
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    From: Scottsdale, AZ
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    Re: I need a clutch dimension...Help!

    MustangSteve wrote:

    Jerry67Fastback wrote:

    used 11" long style clutch disc measures .305

     Thanks, Jerry.  Is that the thicknes of the disc itself?  What I really need to know is the recess dimension of the pressure plate.  If you sit the pressure plate flat on a table and measure the distance between the table and the mounting bolt surfaces, then I will have what I need.  The pressure plate friction surface will hold the body of the pp up off the table a bit.

    If I set the my pressure plate on the table, The distance from the table to the pressure plate disc is 0.140".

    1966, vert, 347 stroker, T5z, 4 wheel disc, pb, 3.70 LS 9", EPAS
     

    8/05/2013 6:37 PM  #8

    KeithP
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    From: Scottsdale, AZ
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    Re: I need a clutch dimension...Help!

    1966, vert, 347 stroker, T5z, 4 wheel disc, pb, 3.70 LS 9", EPAS
     

    8/05/2013 7:21 PM  #9

    MS
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    From: Canyon Lake, Texas
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    Re: I need a clutch dimension...Help!

    Thanks, Keith.  Perfect.  If Jerry's dimension is the disc itself, then it should have a 0.305" thick disc and a 0.165" (=.305- 0.140") clamp dimension, assuming those two parts are compatible.

    That leaves my friend's pressure plate only compressing the disc by less than half that amount.  I think he must have the wrong disc for that pressure plate or a defective pressure plate.

    I emailed SPEC CLUTCHES on their tech line and, of course, got no response.  I don't know why those companies put a tech line connection on their web sites if they are not going to answer the questions.

    If anyone else has more data to confirm Jerry and Keith's dimensions, it would be appreciated!

    Thanks, guys.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
       •Thread Starter
     

    8/05/2013 7:48 PM  #10

    DC
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    From: Marshall, MI
    Registered: 4/01/2013
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    Re: I need a clutch dimension...Help!

    With all 6 bolts finger tight, the gap on my spare race clutch measures an average of 0.153 inches. This is a South Bend performance clutch that is great! Nice pedal force and engages very nicely. Good for over 500HP.

     

    8/05/2013 9:18 PM  #11

    Jerry67Fastback
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    Re: I need a clutch dimension...Help!

    Steve, the figure I gave you is the thickness of the disc.

     

    8/06/2013 7:55 AM  #12

    hmartin025
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    Re: I need a clutch dimension...Help!

    My best recollection is upward of 3/16 inch.
    Howard

     

    8/06/2013 11:27 AM  #13

    MS
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    From: Canyon Lake, Texas
    Registered: 1/24/2013
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    Re: I need a clutch dimension...Help!

    I finally heard back from the SPEC clutch people.  They stated the pull-down of the pressure plate should be ~0.130" and the thickness of the disc should be 0.350".

    I measured the slipping one and got 0.032" disc thickness and 0.070" pull-down.  That is over 0.100" out of spec.  I am waiting on SPEC's answer as to what to do about it.  This is one of those deals where the guy bought the parts several years ago and is just now getting them installed.

    I'll let you know how it turns out...

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
       •Thread Starter
     

    8/07/2013 11:27 AM  #14

    jeremy
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    Registered: 4/14/2013
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    Re: I need a clutch dimension...Help!

    just fyi..those spec clutches are famous in the fox mustang world for doing two things..the first is chatter..they tend to have bad chatter issues, and the second is that they destroy trannies..Spec clutches are amazing..so much to the point that theyre on off switches..which is bad for transmissions.  imo theyre are a lot better choices out there

     

    8/07/2013 5:17 PM  #15

    MS
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    From: Canyon Lake, Texas
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    Re: I need a clutch dimension...Help!

    My suggestion was they he just get a Centerforce and get it over with...  I am putting one of theirs with the dual friction in my car.. I just hope it operates smoothly.  I already tested the cable clutch with it and the pedal effort is alot less than my King Cobra I used to have.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
       •Thread Starter
     

    8/07/2013 5:24 PM  #16

    jeremy
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    Re: I need a clutch dimension...Help!

    ive used several of those..the pedal effort is so light its like a honda.  I did have an issue with the one in my bros mustang..the counterweights were off, causing a vibration..it chews through throw out bearings every 12 months or so...we called centerforce..they said try cutting the weights off.....but to be fair..ive used lots sucessfully...nice clutch

     

     

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