clutch disc separated

[harleydodgeman]

I have a question for all of you guys that have run 4 speeds for a while:

it appears that my brand new, well new 10 years ago, but never used clutch disc is separating. when i have someone push the clutch in, i can look underneath and actually see the clutch disc spreading apart while the pressure plate is disengaging. the problem i am having is that my clutch is not disengaging fully, I can start the car with the clutch in while in 1st gear, but i cannot put it into a gear if i start the car in neutral. it just grinds.

Could the clutch disc actually spread enough and keep "grabbing" the pressure plate? can this even happen or do all clutch discs do this? I am just wondering if this thing has been setting on the shelf to long and whatever holds the disc together is letting go. just doesn't seem right. any help please

 

[fiorock]

Most stock-style clutch discs have what's called Marcel springs between the friction surfaces to make the engagement smoother (less chatter), so it will compress or expand to some degree when the clutch is engaged/disengaged. I think the best way to adjust the clutch is to adjust to achieve a gap between the disc & flywheel when the pedal is depressed - 0.060" I think is what was recommended somewhere (old Direct Connection manual, maybe?). Then make sure you have freeplay when the pedal is released (there should be clearance between the release bearing & the pressure plate fingers). If you can't adjust the linkage to get the right clearance on both ends, you may have to correct or change the geometry (z-bar, pivot ball location, etc.) especially if you have an aftermarket scattershield. I ended up having to do this on mine & made an adjustable pedal stop to get the correct clearance with the pedal depressed.

Don't mean to come off as an expert or anything, but I've raced a stick car for a long time & learned the hard (& expensive) way...

Hope this helps.

 

[fiorock]

Most stock-style clutch discs have what's called Marcel springs between the friction faces for smoother clutch engagement (less chatter), so the disc will compress or expand somewhat when the clutch is engaged/disengaged. Your disc could be dragging if you don't have the linkage adjusted for enough departure. A gap of 0.060 between the disc & flywheel (or press. plate surface) comes to mind from somewhere (either some set of clutch instructions or maybe the old Direct Connection manual?). Just make sure after you adjust for air gap, that you have freeplay when the pedal is released (the release bearing should have clearance to the pressure plate fingers). If you can't achieve the correct gap on both ends, you may have to modify or correct the linkage geometry, especially if you have an aftermarket scattershield. I ended up having to do that plus make an adjustable pedal stop.

Don't mean to come off as an expert or anything, but i've raced a stick car for a long time & learned the hard (expensive) way...

Hope this helps.

 

[harleydodgeman]

thats the kind of info i am after .. thanks.. i wanted someone who has messed with 4 speeds enough to know those kind of things... I have checked all of my clearances, i can actuall turn the clutch disc by hand .. however, it still grinds when i put it into gear like it is not releasing? i just don't get it... thanks for the advice

 

[fiorock]

Sorry about the double post above - didn't show up after I submitted the first time.

Anyway, hmmm...

I was just thinking about a couple of other things that might be causing your problem -
Its possible that if the fit between the input shaft & pilot bearing were tight, the crank could still be driving the trans (but you say you can spin the disc by hand with the clutch released? How easy?). I would also say to check your shift linkage adjustment - thinking maybe the 3-4 slider could still be coupled & you're trying to engage 2 gears at once . Not sure if you have a Hurst shifter, but they usually have a hole or notch in all of the levers that hang out the bottom of the shifter body that you stick an alignment tool (drill bit, allen wrench) through with the shifter in neutral. Disconnect all the levers from the forks at the side cover end, make sure all the trans detents for each gear are clicked into their neutral positions, then adjust the linkage rods so that the slotted hole in each lever slides easily over the slotted tab on each fork stud.

Come to think of it, if you start with the car already in 1st, can you drive it & run up through the gears Ok?

 

[HEMI-ITIS]

Also check for deflection in the z-bar when depressing the clutch.

 

[harleydodgeman]

I have checked my shifter adjustment.. it is a hurst competition plus, using the method you described above, and everything appears to be in adjustment. The car (64 plymouth fury) has been converted over to a hydraulic clutch setup, 3/4" willwood master with 7/8" bore willwood slave. I can turn the clutch disk by sticking my pocket knife in there and kind of "hooking the disk", it will not free wheel, but it does feel ok. As far a shifting gears and driving the car goes, it is a project in progress right now. I have the rear end and everything hooked up, but only for mocking up purposes, basically enough to try and back in and out of the shop to move around. Driving the car isn't quite an option yet. the pilot bushing is bronze and is brand new. Everythign slid together nicely when i was putting the tranny in. Can they be that tight?

 

[fiorock]

I have no experience with hydraulic setups, but from everything you describe, it doesn't sound like its a clutch problem - sounds like maybe the synchros are worn. Have you driven the car with this transmission in the past? When I bought my '69 RR way-back-when, I got it in 'kit' form - most of the driveline was in the trunk. After I got it running I had a similar problem. I didn't have trouble getting it in 1st like you, but I couldn't get it in 2nd unless I slowed to a crawl. Turns out the syncho rings were shot, as were the teeth that the slider couples to on the gear. Its possible you could have a similar issue. You may have to do some exploratory surgery & pull the side cover off. Its also possible the forks could be worn. Earlier transmissions used brass forks (later model steel ones can be retrofitted with a little modification).

Thinking back on other shifting problems I've had - in my quest to shave 10ths off my ET's, I tried using auto trans fluid instead of gear oil at one point. Shifted lousy - kept missing gears. Apparently auto fluid isn't 'slick' enough even though the viscosity is lower. Leads me to ask - you do have enough oil in the trans right?

 

[70Hemi]

I had a problem like that on mine once. was using the 10.95" disc with 10.50 bolt pattern preasure plate (used to be called scalloped) and my outer edge of the clutch disc fiber was rubbing lightly on the preasure plate bolts. you could move it by hand and everything was adjusted and working but with the motor running wouldnt go in gear. I finaly took it back apart and lightly ground the fiber off the edge of the disc and it was fine after that. not sure if that helps but I have been running a 4 speed for 31 years and thats just something I had happen to me good luck

 

[harleydodgeman]

well, i finally got it to move, and i am not sure why it did this time.. i didn't change a thing and the other night was just out in the garage and i started it up. thought i would give it a try just cause. and it worked. i am not sure if something was dragging and holding things up or what but now i push in the clutch and put it into all 4 gears and no grinding. I can just feel the tranny engage each gear though the shifter handle. I would guess that's normal. you should be able to feel something when you put it in gear right? or should the shifter just click into place? I guess i should put it this way... it clicks into each gear but i can also feel the gears spinning and engaging through the handlel if that makes sense. .. i guess i am makin a little head way. think i am maxed out on stroke though with the hydraulic so i may have to check into that. May need a bigger master to make it stroke more? all new to me .. i appreciate all your guys input on this deal