CrazyDude

Hello. Over the past summer, Manolis_D and I rebuilt the motor out of my '91 NA in my garage. The car seems to run fine now, except I beleive there is a problem with the clutch. I am not exactly sure what to ask... please bear with me as I run over a list of my concerns; if you pick up on anything that might be causing the problem or should be of serious concern, please do let me know!

Ok, so the MAIN problem is that the car is almost undrivable.... I replaced the stock clutch with a Racing Beat Street/Strip pressure plate and a RB Heavy Duty Street/Strip clutch disc (the kind that does NOT have a spring inbetween the friction surfaces). The problem seems to be that the engagement of the clutch is EXTREMELY harsh.... for the first half of the clutch travel, there is zero grab, and then all of a sudden it grabs HARD (bogs the motor frmo 2500 to 1000 under throttle), and the rest of the pedal travel is pressure all the way out, but I cant modulate it too much because its already grabbed so hard!

I also just cannot get it to grab gears cleanly without having to pause on the clutch a little... even then there is some bumpiness. This leads me to my first concer:

I have my old motor mounts (still both in one piece) and my old transmission mounts; should this clutch require the installation of competition motor mounts and transmission mounts? I plan on putting those in once I can find a cheap place to get them. When I get the car moving from a stop, if I dont rev it up resonably high (like 1800 or higher), the motor sounds like it is being juggled around in the engine bay.... but I was under the impression that stiffer motor mounts will only make drivetrain engagement even more sudden.... ?

The next of my concern is my flywheel; I got it resurfaced when I rebuilt my motor... the guys at the shop only ground down the actual friction surface but NOT the bits that stick up where the clutch bolts on. I was worrying about this because I was thinking it might be contributing to the uneven distribution of pedal effort?

The last thing, which I just noticed today, is an odd sound when I have the clutch in. Unfortunately, my exahust is somewhat loud, so I can only hear it at idle, but when I put the clutch in, I can hear some sort of rubbing sound... I am not really sure how to describe it, sort like when you have a bent bicycle wheen and it rubs against something at some points. This sound DOES vary with RPM, and can be heard when I am stopped, and only when I have the clutch pedal in.

Also, when I replaced the clutch, I got a new release bearing... whichever one Mazdatrix sells, which I guess is just exact stock replacement?
When I install a non-stock clutch assembly like this, am I supposed to have to adjust something in the clutch hyraulics system?
Do I need to go up to a stainless steel braided line?

As you can probably tell, I am at my wit's end over the problem and dont really know what might be wrong as I am not all too familiar with clutch systems. Any and all advice would be greatly appreciated!

Thanks,
Andrew Pullin

1FastT2

iTrader: (1)

Sounds like a pilot bearing prolbem. I had 2 go bad just because I didnt grease it properly. That would explain the sudden clutch grabbing and the noise you hear when you push in the clutch.

jacob

i agree that the a bad pilot bearing will cause a noise with the clutch pedal pushed in, but i don't think it will sound like a 'rubbing' noise. think about how fast your engine is turning - even at idle. a bad bearing spinning that fast will sound more like a whine than anything. its always a good idea to change the pilot whenever you have the clutch off, its a good investment.
i think your problem could be your flywheel not being resurfaced properly. when you take material off any part of the flywheel, you better take the same amount off the rest of the flywheel. the pressure plate may be designed in such a way that after a certain amount of engagement 'travel', it will clamp down with more force. that might explain why you can't manipulate the clutch very well after it has engaged. i really think this is your problem. unfortunately that means some more work for you

GLHS

did you put the grease cap on before you installed the pilot bearing?

This will make your bearing go out very fast...couple thousand miles... maybe..

Turbonut

iTrader: (1)

I would say the harsh engagement is just the characteristic of the heavy duty assembly. The disc having no springs will not then absorb any vibrations. It's either engaged or not, just a very fine line. Noise either t/o brg, or pilot brg. They're the only 2 parts moving when clutch disengaged. Push in the clutch only slightly to have t/o brg make contact with pressure plate. Not as far as to disengage the clutch. If noise appears it's the t/o brg.
Resurface of flywheel-dependant upon how much was removed. If only a few thousands to clean up should present no problem. Turning the flywheel, if you put it in perspective from a pressure plate standpoint, is no different than when a disc wears. What I'm mean is if the flywheel cut .005 that is no difference then if the disc worn .005 (.0025 each side) with a new flywheel.
Just my thoughts.

CrazyDude

Both my throw-out bearing AND my pilot bearing are new. The grease cap was installed; I have only put 530 miles or so on the whole thing.

To grease it, I smeared a fingerfull of Valvoline Multi-Purpose grease inside it, which I beleive it some sort of lithium grease. Is that the wrong stuff to use? When I put the release bearing in, I did not put any grease or anything on it.

Do I have to remove the engine to change the pilot bearing and the release bearing?

Steel

well i'm not sure "all purpose" grease will cut it for a tranny. I would use special transmission specific i.e. extreme load and temp. grease seeing as how the tranny goes under extreme loads and temps. That's why one puts 90w oil in a tranny and not 10-40.

Mephis

sounds like somebody dont know how to drive a cluth , just let out real easy and dont let off all the way untill your movingh , start giving it gas asoon as it grips

C. Ludwig

iTrader: (27)

Just to add my vote and repeat what has been said.

The release "problem" is just the characteristics of a solid hub clutch. Get used to it or change to a sprung hub. And as Mephis saying you don't know how to drive a clutch don't sweat it. I have a couple friends that drive manuals everyday that can't go ten feet in my track car without stalling.

The shifting problem sounds like a pilot bearing. They're easy to foul up when you install them. Smack the race or cage the wrong way and you have trouble. Seen it happen a couple times.

Chris