Proper clutch fork stud adjustment?
Thread Starter
Race Director
Joined: Sep 1999
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From: Plano TX
Proper clutch fork stud adjustment?
I'm optimizing my clutch linkage since I have everything apart anyway to replace the flywheel (long story involving a slight backfire making pretzels out of a starter & ring gear).
Now I have an adjustable clutch fork ball stud, but I'm not sure how it is supposed to be set. I found one web reference that said the distance from the bellhousing flange to the top of the stud should be 4.75". Another site said adjust the stud so the fork is pointing slightly rearward on the throwout bearing side with the clutch engaged and slightly forward when disengaged.
Anyone have the scoop on this? What adjustment gives the best geometry?
Now I have an adjustable clutch fork ball stud, but I'm not sure how it is supposed to be set. I found one web reference that said the distance from the bellhousing flange to the top of the stud should be 4.75". Another site said adjust the stud so the fork is pointing slightly rearward on the throwout bearing side with the clutch engaged and slightly forward when disengaged.
Anyone have the scoop on this? What adjustment gives the best geometry?
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
I think the stock one is non adjustable. I would find out how long it is and add a little to it. 1/8in or so.
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I always adjust them so that the arm is as close to the pressure plate (angled forward) as I can get it without hitting.
You have to check closely...I've had them touch a spot in just one place and not at others. Not something to find out AFTER it's all back together...trust me I know!
Centerforce gives the 4.75" number I believe....and it's close, but I still go by method above. You want the arm pointing toward front of car when released.
There are actually a couple of different "Vette" type arms with clevis pins in them. They are different lengths and provide different ratios. I can't give you part numbers, but I know the one I had in my old Camaro, wouldn't clear the C-2 floor at full depression...but it did provide good release. Maybe a "parts" guy here will know which one is which.
I also had good luck drilling a new hole about 1" lower on upper arm of crosshaft to speed up ratio without making effort too high. But it will take a heck of a drill or a mill...those suckers are tough!
JIM
You have to check closely...I've had them touch a spot in just one place and not at others. Not something to find out AFTER it's all back together...trust me I know!
Centerforce gives the 4.75" number I believe....and it's close, but I still go by method above. You want the arm pointing toward front of car when released.
There are actually a couple of different "Vette" type arms with clevis pins in them. They are different lengths and provide different ratios. I can't give you part numbers, but I know the one I had in my old Camaro, wouldn't clear the C-2 floor at full depression...but it did provide good release. Maybe a "parts" guy here will know which one is which.
I also had good luck drilling a new hole about 1" lower on upper arm of crosshaft to speed up ratio without making effort too high. But it will take a heck of a drill or a mill...those suckers are tough!
JIM
Thread Starter
Race Director
Joined: Sep 1999
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From: Plano TX
Ok, so no real "GM approved method" then. I'll start by setting it at 4.75" and then test fit it. If the fork is 030-060 away from the PP I'll call it good and weld the nut on the stud (it had come loose).
Thanks.
Thanks.
Le Mans Master
Joined: Apr 2000
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
Markus please let us know how it works out for you. I have an adjustable pivot ball to go into my bellhousing before I put my car back together again 
After installing the new engine last year with a new billet flywheel, I had to adjust my clutch pedal all the way to the end and still didn't have much pedal 
so I'm hoping this is the fix
After installing the new engine last year with a new billet flywheel, I had to adjust my clutch pedal all the way to the end and still didn't have much pedal so I'm hoping this is the fix
Thread Starter
Race Director
Joined: Sep 1999
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From: Plano TX
Popped the tranny back in tonight. I ended up setting the ball stud 4.65" from the flange. The fork still clears the pressure plate (I hope!) and it seemed to give me good geometry. I also welded the stud to the nut.
Team Owner
Joined: Feb 2003
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From: Lake Norman NC
I too ran out of adjustments on my clutch rod..i had a pedal that came right off the floor after installing an aftermarket clutch. I got an adjustable clutch rod for the fork, (14.99 out of summit, i'll give you the pn# if you need it) and gave me so much more adjustments...clutch feels hard and high just the way i like it.
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From: St Louis MO
Originally Posted by Redshark6974
I too ran out of adjustments on my clutch rod..i had a pedal that came right off the floor after installing an aftermarket clutch. I got an adjustable clutch rod for the fork, (14.99 out of summit, i'll give you the pn# if you need it) and gave me so much more adjustments...clutch feels hard and high just the way i like it.
Brett
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Team Owner
Joined: Feb 2003
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From: Lake Norman NC
Originally Posted by Brettmc
Is that a Mr. Gasket? I ordered one from Jegs 2 weeks ago and it's STILL on backorder.
Brett
Brett
Le Mans Master
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
Zwede is this measured from the flange to the top of the pivet ball? I'm going to try that & if I need more, I'll get the adjustable rod like Redshark mentioned.
Thanks guys
Thanks guys
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You can adjust the pivit ball length (when using an adjustable ball) after the bellhousing and tranny are in. You will need a thin open end wrench (I also had to shorted it) and the correct size allen wrench. It's not easy, but you can dial it in perfectly. I like about 1/4" between the throw out and the clutch fingers. Make your adjustments before installing the fork boot.
