Clutch Question

Clutch Question - 03/07/11 12:06 AM

Hi,

I have a 383 in my 68 Charger with a 23 spline 4 spd trans. The trans is rebuilt, and the clutch is a new McCleod 10.95 clutch and a new 10 1/2 inch billet steel flywheel.

My problem is that the engagement of the clutch is right at the top of the pedal travel...meaning that it doesn't engage until I almost completely let off the clutch. I have played with adjusting the clutch and all that does is reduce the amout of pedal travel, not the engagement point.

I have all new nylon bushings in the z-bar, and there does not appear to be any play in the linkage.

In the past, my experience with new clutches is that the engagement tends to be near the floor. Why is the engagement on a new trans/clutch/flywheel near the top? Needless to say, it tends to slip under any power.

Any ideas on what I did wrong here? Any input, good or bad, is appreciated.

Hans

Posted By: RapidRobert

Re: Clutch Question - 03/07/11 01:25 AM

I'm not a stick guy but if it was good b 4 & the only ch was the Mcleod stuff I'm thinking they sent the wrong part, maybe the height of the throwout bearing is now different. but I have ran Mcleod clutches in our circle track car & it's good stuff

Posted By: Pacnorthcuda

Re: Clutch Question - 03/07/11 01:40 AM

If you take off the inspection cover, is the throw-out bearing contacting the fingers of the pressure plate? It shouldn't be! It should be about 1/4 away. If it is touching, grab the linkage and pull and see if its just the gravity of the pedal that causing the contact (if so install a stronger return spring under the car--not the one under the dash).
But if you find the throw out bearing is in STRONG contact with the fingers then THERE's the problem. Figure out why, pedal linkage must be binding up somewhere.

Posted By: Hans68Charger

Re: Clutch Question - 03/08/11 12:16 AM

Thanks, I am pretty sure that the TO bearing is not resting up against the fingers. The freeplay measured at the pedal is about an inch.

My thought is that the disk or flywheel is not the correct thickness...or possibly the TO bearing is not the correct one. Any thoughts on that?

Does anybody know off hand what the correct thickness for the disk and flywheel? I guess I can call the manufacturer.

Posted By: John_Kunkel

Re: Clutch Question - 03/08/11 12:51 AM

Forget about the free play at the pedal and set the gap at the fork at 5/32" like the factory says. Be sure there is a return spring at the fork.

If the clutch still engages high its just the nature of the beast or you have the wrong fork.

Posted By: Pacnorthcuda

Re: Clutch Question - 03/08/11 02:29 AM

Quote:

Thanks, I am pretty sure that the TO bearing is not resting up against the fingers. The freeplay measured at the pedal is about an inch.

My thought is that the disk or flywheel is not the correct thickness...or possibly the TO bearing is not the correct one. Any thoughts on that?

Does anybody know off hand what the correct thickness for the disk and flywheel? I guess I can call the manufacturer.

Couple thoughts:
Flywheel thickness is not an issue here--The amount of pressure the pressure plate will exert in the 'relaxed' position will be the same if the plate is 1/4" or a mile thick.

The disc thickness will affect pressure--but its not likely, unless you have a seriously miss-matched disc and pressure plate.

TO bearing wrong?? All it does it actuate the fingers, if its too "long" then you risk it always being in contact with the fingers, and you dont think thats the case. If its too short, then you would have a lot of free play, but engagement would be farther to the floor, and the pressure plate would still be exerting its max force on the disc.

Could you have a defective pressure plate? A contaminated (oil) disc?
Glazed disc?
Could the pressure plate itself be binding up--I would watch its action as a helper engages and dis-engages the clutch.

Posted By: Hans68Charger

Re: Clutch Question - 03/08/11 01:33 PM

Quote:

Forget about the free play at the pedal and set the gap at the fork at 5/32" like the factory says. Be sure there is a return spring at the fork.

If the clutch still engages high its just the nature of the beast or you have the wrong fork.

I actually did check the air gap and it was within spec. The wrong fork is something I had not thought of. My four speed system is put together with a bunch of parts scavenged from other cars. Thanks

Quote:

Couple thoughts:
Flywheel thickness is not an issue here--The amount of pressure the pressure plate will exert in the 'relaxed' position will be the same if the plate is 1/4" or a mile thick.

The disc thickness will affect pressure--but its not likely, unless you have a seriously miss-matched disc and pressure plate.

TO bearing wrong?? All it does it actuate the fingers, if its too "long" then you risk it always being in contact with the fingers, and you dont think thats the case. If its too short, then you would have a lot of free play, but engagement would be farther to the floor, and the pressure plate would still be exerting its max force on the disc.

Could you have a defective pressure plate? A contaminated (oil) disc?
Glazed disc?
Could the pressure plate itself be binding up--I would watch its action as a helper engages and dis-engages the clutch.

Good thoughts. I am going to do what you suggest and get my brother over to help me out. Thanks alot for the input and suggestions.