I'm leaning toward the Tilton rather than the Quartermaster because the Tilton's carbon disks will be much more tolerant of abuse than the QM's organic lining. Price might still change my mind. I'll have to check that on Monday.

What exactly is "horking" a clutch?

SWEET! Page 3!

[This message has been edited by Will (edited 01-25-2003).]

I guess "horking the clutch" would be to cause irrepairable damage to it.

quote Originally posted by bushroot: On/Off eh? I E-mailed a company that sells SPEC clutches. Hopefully, the model they sell for the Cavalier with an Isuzu will work. Pretty impressive numbers. I was thinking about using the stage 3 which is supposed to handle 360 lb-ft. Or, I could get ballzy and try the stage 4...might not be very streetable though.

I checked that website, the part number you want for a Fiero Stage III clutch is SC883, not SC863.

Dave

quote Originally posted by California Kid: Clutch pedal effort with the QM unit is only slightly above stock clutch (not objectional at all). Have never had a problem with my crappy Fiero hydralics/clutch arm bushings.

I was speaking in reference to Will's comments he got from the Tilton tech guy, of the increasing force at the last half of pedal travel (I assume due to the nature of the travel path of the clutch arm). I know you can't expect a fantastic clutch to be completely soft, I wouldn't even want that, as feedback is always good.

I know my own clutch arm bushings are fine at 180k miles, but I've heard people that have worked on a lot more Getrags than me say they are a common failure in the 100k+ mileage range. Also, the Fiero hydraulics have a lot to be desired. I had to replace my slave (did master while I was at it) at 165k, which is pretty good for OE in that much heat. I would, however, much rather have a hydraulic throwout rather than a clutch slave and clutch lever. It would give more linear force, eliminate the *potential* failure of the clutch arm bushing, and hopefully increase reliability/durability with a high end aftermarket unit. Plus, like Will seems to relate to....it's just cooler to have the "cool stuff" that gets the job done, instead of just getting the job done.

My .02 bucks anyway.

Bryce
88 GT

Thanks for the part #. It's great that everyone is so supportive of each other's projects. Wish the SHO forum I'm on was equally as helpful.

quote Originally posted by Nashco: I was speaking in reference to Will's comments he got from the Tilton tech guy, of the increasing force at the last half of pedal travel (I assume due to the nature of the travel path of the clutch arm). I would, however, much rather have a hydraulic throwout rather than a clutch slave and clutch lever. It would give more linear force, eliminate the *potential* failure of the clutch arm bushing, and hopefully increase reliability/durability with a high end aftermarket unit.

The disengagement force increases because the stock Getrag throw out bearing is larger in diameter than what the Tilton clutch was designed for. That means that as the TOB pushes on the release fingers and they pivot far enough, the outside edge of the TOB will be pushing on them, rather than the inside edge. This moves the point of application of force much closer to the release finger pivot and reduces the mechanical advantage, increasing the release effort. It has nothing to do with the rest of the throw out mechanism and only anything to do with the shape of the face of the throwout bearing.

I disagree with you about the hydraulic release bearing. If anything goes wrong with it, you'll have to pull the engine to fix it. Also when you pull the engine you have to disconnect it, which means dealing with the possibility of spilling brake fluid and bleeding it when you put the engine back in. I find the stock setup convenient for maintenance, and haven't had any serious problems with it.

Besides, going to a hydraulic throw out is MORE fab and engineering work that has to be done. I know it has been done, but I don't remember by whom or where to find the info right now.

California Kid: I remember you mentioning something about putting a chamfer on the stock TOB. Are you in a similar situation with your clutch?

quote Originally posted by Will: California Kid: I remember you mentioning something about putting a chamfer on the stock TOB. Are you in a similar situation with your clutch?

It works fine with the flat or conical bearing, just feel that conical is a little better design for longer life of the pressure plate fingers. You don't get much wear with either of them, just a little less with the conical bearing. I'm using a conical NSK PN 61TKB3001 (made in Japan), that works great.

quote Originally posted by Will: The disengagement force increases because the stock Getrag throw out bearing is larger in diameter than what the Tilton clutch was designed for. That means that as the TOB pushes on the release fingers and they pivot far enough, the outside edge of the TOB will be pushing on them, rather than the inside edge. This moves the point of application of force much closer to the release finger pivot and reduces the mechanical advantage, increasing the release effort. It has nothing to do with the rest of the throw out mechanism and only anything to do with the shape of the face of the throwout bearing. I disagree with you about the hydraulic release bearing. If anything goes wrong with it, you'll have to pull the engine to fix it. Also when you pull the engine you have to disconnect it, which means dealing with the possibility of spilling brake fluid and bleeding it when you put the engine back in. I find the stock setup convenient for maintenance, and haven't had any serious problems with it. Besides, going to a hydraulic throw out is MORE fab and engineering work that has to be done. I know it has been done, but I don't remember by whom or where to find the info right now. California Kid: I remember you mentioning something about putting a chamfer on the stock TOB. Are you in a similar situation with your clutch?

You're right, if something goes wrong with it you will have to replace it. With a high quality part from someone like Tilton, do you see that being a common problem, though?

I don't understand why you would have to disconnect the TOB when removing the engine? From what I've seen and understand, the TOB stays with the tranny just like a clutch lever would. The lines can be routed through the tranny case, one for the pressure side and one to the bleed/outlet port. If I'm correct in how this works, there would be no problems with fluid leaking or bleeding it.

I suppose I may be being a little naive about this, or perhaps I'm more ambitious than most, but the hydraulic TOB doesn't scare me as far as design goes. I've been asking about them because I plan on using one on my 4.3 V6/Porsche 5 speed/VW Bug project. There isn't much room for a clutch arm in the stock location, so I actually think a hydraulic TOB will simplify things.

Does anybody have any experience with the hydraulic TOB? I know many OEMs have used them with varied results, but they usually last about the same as a normal slave cylinder. I *assumed* that the high end aftermarket suppliers could make a part of much better quality and durability, as their stuff is being used in top quality pro race cars. Thoughts?

Bryce
88 GT

CK:

Do you have any more info on that TOB?
I tried putting it into the P/N search at www.tec.nsk.com and it didn't come up with anything.

The E4203 .pdf catalog here: http://www.nsk-corp.com/page.asp?ID=315 describes NSK release bearings, but doesn't have any P/N info.

[This message has been edited by Will (edited 01-26-2003).]

What really would be the advantage of going to a hydraulic throw out rather than the slave/arm setup?

quote Originally posted by Will: CK: Do you have any more info on that TOB?

That's all I have, nothing special about it, just ordered a replacement bearing for an '88 GT from local parts store. The numbers I posted are stamped right in the case stamping.

quote Originally posted by Will: Since the bearing is INSIDE the bellhousing, it has to be disconnected from the hydraulic line when the engine/transmission is removed. (You can't pull the engine and leave the trans in a V8 Fiero, especially a Northstar).

Duh...I wasn't thinking about removing the cradle from the car, even though that's how I do it. My bad, total brainfart...thanks for keeping me in check.

quote This then requires that the clutch system be bled when the engine/trans is reinstalled. Here's where it gets tricky. When you bleed the system, you're trying to force air DOWN into the cylinder so that it can then come UP out of the bleed line. You can get around this by reworking the Fiero clutch line to come to the bottom of the bellhousing and drilling a hole for it in the bottom of the bellhousing, but then you still have to orient the bearing properly so that air only has to go UP to get out of the bearing... I just see it as being a giant headache trying to retrofit one to a system--particularly one like the Fiero's--that wasn't designed for it. In short, the stock Fiero system has only two high spots: master cylinder and slave cylinder. Unless your quite careful in redesigning things, you might end up with more high spots in the system with no way to bleed them.

I did a real quick modification to Orville's picture, showing how I would do the hydraulic TOB on the Getrag. Sure, there are many ways to do it, this just seems to me to be the best way for fluid/air travel with the part Orville used.

Luckily, on my VW project, I can pull the engine without even thinking about touching the trans. The new chevy setup will add a few extra steps to engine removal, but it will still only take a couple hours to get to the TOB on this project, thankfully.

I know...Murphy's law applies to everything, but I suppose I'm an optimist. Pulling the cradle is a hell of a lot tougher than putting in a new slave cylinder. By no means am I saying the hydraulic TOB is the BEST solution for your situation. I made a comment that I'd rather have the hydraulic TOB than the normal Fiero setup...that doesn't mean much, as I'm about two years from having my N* project to that stage. I'm more interested in finding the proper hydraulic TOB for my Porsche tranny, as I actually need it now, not just saying it would be cool to have.

bushroot...there are few advantages to the hydraulic TOB. One is few parts to fail or wear(such as the arm and pivot bushings). The other is you can easily adjust pedal pressure or clutch travel with different bore size on the clutch pedal. Lastly, the reason I am using it, is the packaging aspect. I have no room for an external slave on my application, so I'm putting it inside the trans. In the case of the Fiero, it would allow more room for things like exhaust pipes, alternate shift mechanisms, etc.

Bryce
88 GT
*edit: forgot the picture*

[This message has been edited by Nashco (edited 01-26-2003).]

I see...I've just never seen a hydraulic throw out. It makes sense, especially if you're doing the big engine/little car thing Might have to look into this. Damn it guys...every time I look up, I'm going to be spending more money

quote Originally posted by Nashco: I did a real quick modification to Orville's picture, showing how I would do the hydraulic TOB on the Getrag. Sure, there are many ways to do it, this just seems to me to be the best way for fluid/air travel with the part Orville used.

You could do it this way. Just remember that the trans in the picture is NOT a Getrag, and the Getrag is a little different inside the bellhousing.
Another thing to consider is the stock clutch line routing. It's designed to go in a slave cylinder that would be off the top edge of this picture. Will the flexible portion have to come back down to get to the proposed bellhousing connection for the hydraulic TOB "in" line? Are you ready to re-bend the stock line or replace it entirely to fix any problems you might run across?

Getrag Bellhousing internal for discussion:

quote Originally posted by Will: You could do it this way. Just remember that the trans in the picture is NOT a Getrag, and the Getrag is a little different inside the bellhousing. Another thing to consider is the stock clutch line routing. It's designed to go in a slave cylinder that would be off the top edge of this picture. Will the flexible portion have to come back down to get to the proposed bellhousing connection for the hydraulic TOB "in" line? Are you ready to re-bend the stock line or replace it entirely to fix any problems you might run across?

Sheesh...tough crowd.

Yes, I assumed it was obvious the line would need changed (you know what they say about assuming, though ). I know how fluid, air, and gravity interact...you are right, the line would need re-routed. I would be willing to create a new line, yes. I will be using all new lines in both my VW and my race Fiero project; it's not hard to do, really. If someone can figure out how to put all of the clutch parts together for such a setup, they'll probably also know how to bend and flare pipe.

I went ahead and made another quicky with a Getrag...not much different than the last one, but it wasn't a Getrag before...now it is.

Bryce
88 GT

There's a guy named Terry Haines who lives near me. He was one of the engineers on the Ford Duratec project. He does a lot of custom work on SVT Contours, Cougars, Jag X-types, etc. He builds what he calls a "Bulldog box". This supposedly raises the torque handling capabilites of the MTX-75 Getrag from about 300 lb-ft to about 700 lb-ft. He does this by pumping the oil through the tranny and a cooler and adding a Quaife. I'm sure there are more mods, but that's the only one I know of for sure. His outfit is called Haines Motorsports. I wonder if some of the same techniques could be applied to our little getrag to make it more reliable under increased loads.

quote Originally posted by bushroot: There's a guy named Terry Haines who lives near me. He was one of the engineers on the Ford Duratec project. He does a lot of custom work on SVT Contours, Cougars, Jag X-types, etc. He builds what he calls a "Bulldog box". This supposedly raises the torque handling capabilites of the MTX-75 Getrag from about 300 lb-ft to about 700 lb-ft. He does this by pumping the oil through the tranny and a cooler and adding a Quaife. I'm sure there are more mods, but that's the only one I know of for sure. His outfit is called Haines Motorsports. I wonder if some of the same techniques could be applied to our little getrag to make it more reliable under increased loads.

That's pretty much standard on race-prepped transmissions. The oil is injected where it is needed the most, and most often cooled externally as well. That would surely help if you were using massive power through the getrag with race-type abuse, however, there are weaker links. I think that the case itself is one of the weaker links, and for actual race use some strong supports would be a big plus. Also, going to straight cut gears would help to eliminate some of the flex of the case. There are lots of little things you can do to the trans to beef it up, but very very few of them are cheap. A full race prepped transmission is cheap at 5k plus choice of diff, from what I've seen.

Oh, and yes, the same techniques can be applied to nearly every single transmission out there. It's not like a kit, it requires lots of custom work and fairly technical knowledge...neither of which come cheap. So, you can deduct that very few getrags have ever seen this treatment, since it's basically only done by top racers. Just my 2 cents.

Bryce
88 GT

100 posts!

I just emailed Herg86GT some pictures of the new CF clutch which arrived today.

The straps have been tripled up, and the design of the disk hub seems to be different, although I hadn't really looked at the old disk to wrap my brain around how it was put together. We'll see how the combo holds up.

I talked to a Tilton tech guy. I'd need the Tilton 44 mm bearing to use with the Tilton clutch, and I'd need to have a carrier machined for it to make it work with the Fiero throw out mechanism. I'd also have to change to a larger slave cylinder and make a slave cylinder adapter and longer pushrod to deal with the Tilton's shorter disengagement throw than stock.
The downside is that the Tilton clutch MSRP's at $3000

I guess I'll be calling QM pretty soon...

Posting for Will:

I've been running the QM/Getrag/N* for 4 years now. When I put it all together they didn't have a hydraulic throwout bearing that would fit a Getrag. Now, I'm getting ready to swap the engine and replace the tranny with a FWD low milage getrag with a torsen diff in it. The FWD tranny has a different throwout arm and slave attachment bracket. It looks like the hydraulic TO bearing may be the way to go back with this new setup, although the current stock MC and 85 Slave have been a good combination and never given me a bit of trouble. The pictures that were posted of the HTO bearing, has this been actually done and did it run okay with a QM clutch?

I tried to fit a QM hydraulic release bearing in a Getrag a few years back and it hit some metal bosses in the housing. May have been the wrong bearing.

Will is correct, it the bearing goes out you gotta pull the whole thing, but the same applies to the clutch or stock TO bearing.

A $3k clutch eh...jeeezus

quote Originally posted by wcapman: Will is correct, it the bearing goes out you gotta pull the whole thing, but the same applies to the clutch or stock TO bearing.

Not everyone!!! You guys might want to consider modifying the cradle to a "Swing Away Type". Keith Huff in CA modified my cradle so that the left half can be removed without moving the engine to do quick clutch changes. I don't have all the specifics, but photo gives you an idea.




Modified cradle actually performs better than it did in stock configuration.

Dammit! I just lost my whole message, so I'll shorten it this time...

I've been very impressed with the simplicity in Tom's cradle, as he's shown it before. When I had the cradle out last, I decided it would be pretty easy (not a cakewalk, but not much challenge) to make a cradle like Tom's that allows quick trans removals. Obviously, things like throwout bearings, tranny input seals, rear main seals, and clutch failures are a pretty annoying failure to have to pull the whole cradle/engine apart. I feel with any serious performance cradle, it makes complete sense to spend the time to modify the cradle and save time in the future. This is somewhat unrelated to the post at hand, but I really do admire the simplicity and benefits of Tom's cradle. I plan to use the idea and run with it on my own cars in the future.

I emailed Orville to try and get some response on if he ever got his hydraulic TOB functional. Hopefully we hear the info on that, if there are some reasons it wouldn't work specifically for his car it may be helpful in knowing our basic limitations.

Bryce
88 GT

Hi guys. This post is in reply to Nashco's PM
request for more info about my hydraulic (internal)T.O. bearing.

Unfortunately, I can't tell you much about long-term use because I've had some big-time engine problems - sudden loss of oil pressure, spun rod bearing and continuing low oil pressure after having the crank turned and the bearings replaced, a problem still not resolved. Aside to Ls1swap: does misery love
company?

Anyway, for the few miles I was able to drive
it, the clutch and T.O. worked great. Doesn't
require excessive pressure to disengage and
is quit smooth shifting, although a little
sudden starting out in low.

Bleeding is a cinch; I just raise the front of
car till the master cylinder is above the slave, pour fluid into the reservoir until it
comes out at the slave bleeder line, and then
pump the pedal 2 or 3 times. Gives good, firm
action every time (I've done it several times).

Also, with the stock master cylinder, the
slave requires much less travel. I had to put
a stopper on the master cylinder rod to limit
travel.

Nashco, I gave a URL to the Howe site on the other thread you referenced. They have the same T.O. for a better price.

Orville

quote Originally posted by Her86GT: Posting for Will:

Thanks!

One thing I'd like to point out about CK's cradle is that it has a third cradle rail added in, I assume, to pick up the bottom of his engine/trans adapter plate. His engine is fully supported when his trans is removed. My engine is poly mounted, and the mounts don't line up on the engine's CG, so I'd have to tie up some extra equipment to support the engine while the transmission was off. CK also has a cut in his frame rail. I don't know if I'd be able to move the transmission off the engine far enough to disengage the input shaft splines with my engine in the stock location and my frame rail intact.

I think it's a great idea, it's just fairly specific to his car right now and may need some more consideration to be adapted to the general Fiero populace.

Orville: what clutch are you using? Engine? How did you arrange your pedal stop?

Will: Here is a link to the thread describing my setup.
https://www.fiero.nl/forum/Forum2/HTML/031481.html

The clutch is a 2 disk quatremaster 7.25" v- drive model.
For a stop, I used a strap hinge about 2" long
bolted around the rod with 1/4" bolts.

To adjust it, I tightened the strap just snug and with the trans in gear and one rear wheel
jacked off the ground I depressed the clutch
just past the point where the wheel would turn
freely and then tightened the clamp fully.

Orville

Sneaky guy Orville, linked right back to this thread!!! LOL

quote Originally posted by Orville: Unfortunately, I can't tell you much about long-term use because I've had some big-time engine problems - sudden loss of oil pressure, spun rod bearing and continuing low oil pressure after having the crank turned and the bearings replaced, a problem still not resolved. Aside to Ls1swap: does misery love company?

Hey Orville, LS1's (and LT1's for that matter) on Mobil 1 have notoriously low oil pressure (just ask FieroLT1!!). I see about 17-35PSI on my C5, which is lower than any of my other cars even at idle. It's normal.

Now back to our regularly scheduled programming!

Dave

CA Kid: Did I do that? Yes, I did. Well blame it
on the clip board - does strange things sometimes.
Try this one.
https://www.fiero.nl/forum/Forum1/HTML/021428.html

Thanks for the info Orville...good to know it's not too tough to use the hydraulic TOB if need be. I ass-ume that it should go about the same for the Getrag, or any similarly packaged trans for that matter.

Bryce
88 GT