Clutch slipping

[73novaguy]

If I adjust the clutch linkage (Z-Bar) one direction, the clutch slips under full power and shifts fine. If I adjust the linkage in the opposite direction the clutch grabs, but will not shift. Talked to Jeff at CC5S and he thought I might have to long of a clutch fork (fork is for a 73 Chevy Nova) so they sent me a shorter one that originally came on 67-72 Chevrolets. My question is! Has anyone else had this problem? I am about to tear the tranny out in the morning and just wanted some insight from the guys that have ran into this! The engine is a 502 and I had to install a Scoggin Dickey bracket that bolts to the bellhousing in place of the original ball stud for the Z bar pivot (502 has no provisions for a ball stud). Seems to me that the Z-Bar is also angled slightly. Like the motor end needs to go more towards the rear of the car. I did have to cut 13/16 out of the length of the Z-Bar to keep from shimming the frame bracket! Anyone got any ideas!????

[osdmike]

HI !
If there is a linkage problem , You may find some info here.

I have built a similar clutch linkage for My -69 Camaro (454c.i),
I have not tried it out with engine running yet , but it feels Ok.

http://www.chevyhiperformance.com/te...ild/index.html

http://www.chevyhiperformance.com/te...ld/index1.html

#OSDMIKE"

[73novaguy]

Thanks a bundle, looks like a great setup to help stiffen the clutch linkage and also at same time smoothen it out! Any other ideas as to why I am not getting full engage or disengagement?

[HILROD]

The shorter clutch fork is a good start, but check to make sure your body mounts aren't getting loose. A few others have had that be a cause to problems like yours. FRANK

[73novaguy]

Checked body mounts and they are good! I installed polyurethane body mounts a couple years ago! I wonder if maybe they are affecting anything. And I also installed the new shorter clutch fork last night and when I took the old one out, it had a groove wore in the bottom side of the fork from rubbing on the scattersheild. The shorter fork makes it feel like it is grabbing more but the car starts motion immediatley off the floor! So that means I about have to put my foot through the floor to get it to shift correctly and not notchy!

[Tiger]

well, whats the problem then??? its only a lack of muscles in your legs :o)
are you able to lenghthen the pushrod to or from the z-bar in some way? or maybe move the z-bar on furher down on the pedal shaft?

[73novaguy]

I have been dealing with Classic Chevy and there main tech guy Jim who is very pleasent to deal with. The whole company has been very pleasent to deal with. I tried the shorter clutch fork and it gained me a little bit, but it is still slipping.

I have 1012 miles on the clutch (dual friction McLeod) and would think it would have been broke in by now. If I adjust the clutch to grab I have to put a foot through the floor and I have been lifting alot of weights, but I don't want a monster left leg :-) I adjusted the Z-Bar out some to give me a little less free play but better clutch feel and now it shifts great but slips. If I dump the clutch in first or second gear it does not slip because the tires to spin, but if I am cruising around 35 or so in fourth and purposely try to get the clutch to slip and dump the cutch, it will smoke the clutch bad.

Jim also recomended that I try to put a few more miles on it to break it in better and then if it is still not better, maybe try to drill a new hole in the clutch pedal to gain some travel on the Z-Bar. I will try, but the way it smokes the clutch, I am skeptical! Any other thoughts?! The drag strips last test and tune day (Earlville Ia) is this Saturday and Sunday and I am planning on running slicks and 175 shot of NOS. I ran 10.78 with the auto and want to duplicate it with the manual!

[73novaguy]

Just talked to McLeod also and they also recomended drilling either the clutch pedal or the Z-Bar to induce more travel! I'll try it out and write back to let everyone know how it came for future members will the same trouble!

[osdmike]

You mentioned ,drilling a hole in the pedal.
Here´s what I did. (see pic.)
Pedal in picture ,under construction (not finished) , but You get the idea.
I haven´t been able to try it yet , but it gives Me
a few more alternatives ,to adjust , and also to extend the pushrod .
I use spherical rod ends.

"OSDMIKE"

[Tiger]

I'd drill it before you eat up the clutch, if not happy with it you can just put the pedal rod back where it was.

let us know!

[malihoochie]

Osdmike - is that the Godzilla version of a brake pedal in the 2nd pic? Where did that come from? Is anyone missing a length of railroad track?? Nice work on the extra adjustment holes!

[6'9"Witha69]

Osdmike - is that the Godzilla version of a brake pedal in the 2nd pic? Where did that come from? Is anyone missing a length of railroad track?? Nice work on the extra adjustment holes!

Looks to be a standard Wilwood pedal for the Dual master brake setup.

[osdmike]

Yes! Here it is .

http://www.wilwood.com/Products/005-...mcbp/index.asp




"Osdmike"

[73novaguy]

Still the same outcome! I've tried everything from drilling new hole in clutch pedal to drilling new hole in Z-Bar. Still having the same symptoms. When I did drill the lower hole in the clutch pedal and had full travel, it would still slip. I did notice however that when I had the linkage setup out as far as it could possibly be that when I pushed the clutch pedal down about half way down the stroke the pedal would get easy (as in I am going past the highest pressure point of the clutch disengaging). It just seems to me that when I adjust it all the way so the pedal has a very high amount of play, I get good clutch grab, but shifting is all but diminished and when I come out some my shifting comes back but slipping begins! Is this a linkage problem or could it possibly be a pressure plate issue? I am going to the drag strip tomorow and would like to have a clutch! This winter I might go hydraulic, but for now the manual will have to do for. And when I do go hydraulic will I be having the same issues? HELP!!!!!!

[osdmike]

Hi!
Did You measure upper pushrod travel length ? (Blue arrows)

I had to widen up the angle (red arrow) on Z-bar , in a more upright position , to achieve correct travel length.
If I remember it right , I have approx. 2,5" travel length between blue arrows. I´ll get back to You with that info later.

The angle on z-bar may differ between cars.
See if You can find an other one for comparison.



"Osdmike"

[73novaguy]

Hey guys sorry for the long wait. I have not been able to get the clutch to grab yet! it is still slipping in the 3rd or 4th gear range! First to gears have enough tire spin to not notice it. I took the car down to the track a week or two ago and mounted up a pair of slicks to try out some tricks listed here for clutch engagement. Before i even got to the line I busted off two wheel studs (screw in studs, that screwed out when I put slicks on). So I remounted the street tires just to run down the track. So I have not been able to tell how well the clutch is in the first couple of gears. What I do know is that it still slips in 4th. I don't know if it is the pressure plate or what. I will be contacting CC5S to see what they want to do about it. They have been very good to me. The car did run 12.2 at 120 on hard street tires spinning through three gears and feathering throttle all while driving 2 hours round trip and only using 3/4 tank of gas. I am very pleased with my TKO just need to get the clutch issue straightened out. So for the guys still wanting 5 or 6 speeds. I wouldn't even think of another company to buy from other than CC5S. Great group!

[RKHiPerformance]

Hey Justin...

Any updates on this issue?

Is it possible that the Scoggin-Dickey ball stud doesn't properly position the Z-bar?

[73novaguy]

Anybody have any other suggestions! The car has been parked since last fall and will be getting it out soon. Still dealing with the clutch issue. I've had the tranny out twice and want this time to be the last if at all feasable. Just curious if anyone else has run into this since last fall!
Justin

[3pedals]

you may have " glazed" the disc badly the first/second time you let it slip while under power. after you fixed the linkage leverage ratio, the clutch will not grab because its now glazed - check that out and also go through your complete clutch linkage to check for unseen setup stuff you may have overlooked before. if none of this solves the problem, it sounds like an actual clutch problem
what kind of clutch are you running?

[craig]

hi, I dont know if this helps but i ran into the exact problem on a mustang after installing a new flywheel clutch and pressure plate customer supplied parts not really a ford guy. anyway i tried all types of stuff new shift cable ( thought it was streching ) aftermarket cable same problem. replaced pedal pivot bushings same problem, new fork etc... turned out being the wrong pressure plate. just because it bolts to flywheel and the spline is the same doesnt means it the right one.