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I got the .050" from another forum/thread. I don't remember exactly where.
As far as the slave cylinder goes. The throw on the slave rod is entirely dependent on the volume displacement of the master cylinder and the volume of the Slave. The actual slave cylinder movement range of the stock LT1 slave cylinder is far greater than what the master cylinder moves it.
The Fiero slave has a throw of 1.1". I need .655 at the slave cylinder rod. With the stock Master Cylinder on the LT1 the slave will move .704" giving me .537" at the throwout bearing. That's close in tolerance to what's needed.
I forsee a couple issues with the Fiero slave cylinder: The throw being so close to the tolerance making the pick up point at the top of the travel. And, the fitting from the quick disconnect LT1 hydraulic hoses to the threaded port on the Fireo slave cylinder. The first one can be taken care of with an adjustable master cylinder (I can mod that if needed.
The second is a bit harder. There's really not definitive information given on either hose fitting sizes. I can see in this picture about what size I'd need for the quick disconnect, the threaded portion of this coupler is AN-3. This coupler is made specifically for the LT1 slave
cylinder.
I've tried to do some research on the Fiero slave cylinder, but as much as that's an enthusiast car, they are still few and fare between. From what I've found, the closest I could find is the fitting size is possibly M10x1.0, but I'm not sure what side of the clutch line they were talking about (or what clutch line for that matter as there are a couple for that car). I've ordered the slave cylinder ($15) and I'll see in person what the thread size it. Then I'll order the adapters from there.
The other issue is the mounting bolt pattern between stock and the Fiero, but I can mod that to work. So it's not a big deal. After that it's trying to figure out mounting depth. I'll be comparing the Fiero slave to the Stock LT1 slave cylinder when I get the Fiero one in.
Good deal on the street twin. I have one on my car as well with the HD master cylinder and steele flywheel. I did take a little driving to get used to it. Engagement feels great, it is grabby and the takes a little more effort to engage but nothing that is a deal breaker.
I'm making progress on the Fiero slave cylinder. Some info regarding that. Its a 15/16" slave which gives me the throw I need. The pushrod from the stock slave fits perfectly in the Fiero unit.
The Fiero slave has a bleeder screw and the port for the line is a M12x1.0 fitting size. The stock LT1 looks to be a steel braided 3an hose; I'll confirm this later (Update: It's not). Right now I'll order the M12x1.0 banjo bolt with seals and a 3an compression fitting to banjo end adapter. I'm going to cut the stock line for this conversion. I may opt to go with a an AN3 male threaded fitting to 3AN hose compression fitting and then do a female AN3 threaded to banjo end fitting. Either option works, but the second one allows me to quickly adapt the modified line back to a stock quick disconnect for about $15 With just a couple wrenches. (EDITED M10x1.0 to M12x1.0)
The bolt pattern between the stock slave and the Fiero are different widths. I had some scrap 1/4" 6061 aluminum at work so I fabbed up an adapter plate. I've already installed it and made sure the slave is in the middle of its travel so it's not bottoming out in either direction when installed and all is good.
I'll have more info on this in a couple weeks as more parts come in. For now here's the slave with the adapter I made.
I'll take installed pictures when I get it final installed and the adapter is painted all pretty. Lol
Geat clutch. You can actually replace the disk later on if you need to upgrade this to a rxt clutch for half the cost. I had one in my Mustang and gto. You think this clutch is bad you should ride in my goat with a 4 puck unsprung ceramic. No need for leg presses at the gym.
Geat clutch. You can actually replace the disk later on if you need to upgrade this to a rxt clutch for half the cost. I had one in my Mustang and gto. You think this clutch is bad you should ride in my goat with a 4 puck unsprung ceramic. No need for leg presses at the gym.
Good info. I was wondering about replacing just the discs. The PP looks like a stock LT4 unit so that'll be easy enough to come by. The flywheel and floater plate should be good for a couple resurfaces I'd think.
The smaller slave should make for a slightly stiffer pedal, but nothing noticeably different than stock under a leg. I don't mind my dual friction clutch, I just stay out of the chatter range so it's no biggie.
Good info. I was wondering about replacing just the discs. The PP looks like a stock LT4 unit so that'll be easy enough to come by. The flywheel and floater plate should be good for a couple resurfaces I'd think.
The smaller slave should make for a slightly stiffer pedal, but nothing noticeably different than stock under a leg. I don't mind my dual friction clutch, I just stay out of the chatter range so it's no biggie.
Same here iv gotten use to the harsh clutchs it's funny watching ppl try to drive it or even just move it 10 feet
Man the $ you paid for the clutch and the larger slave mod, that bleeds also, wow you will likely have the cheapest Twin disc clutch on the road.
Nice job on the slave refit.
That was the goal! The slave cylinder is smaller though. The stock slave is 1" (there's another option of a 1.25" slave too, that is probably the one people report not disengaging with the Twin disc).
I know you did some math on this to determine how much travel you get out of the slave with the combo you have.
I know McLeod says, which is why they include in the kit, you need a larger MC. 13/16 vs 3/4. The MC gives the stock slave more "stroke" for the Twin to disengage. Pushing the fork in more can, in some cases, result in fork hitting PP which is why some, including me, had to trim down the "T". I know you said you were just doing that preemptive.
So with the smaller bore slave you get more extension using the 3/4" stock MC?
I know you did some math on this to determine how much travel you get out of the slave with the combo you have.
I know McLeod says, which is why they include in the kit, you need a larger MC. 13/16 vs 3/4. The MC gives the stock slave more "stroke" for the Twin to disengage. Pushing the fork in more can, in some cases, result in fork hitting PP which is why some, including me, had to trim down the "T". I know you said you were just doing that preemptive.
So with the smaller bore slave you get more extension using the 3/4" stock MC?
Yes. You can increase the master bore or decrease the slave bore to achieve the same results.
So time for an update. I got the clutch installed and left the stock slave cylinder installed. I left it on jacks and started the car. In 1st with the clutch in the tires didn't move, then I engaged the clutch and got the tires moving, then released the clutch and the tires kept spinning. I applied the brakes and let off the brakes and the tires would stop and spin as I did that. They would get to about 5mph. So, with the stock slave and master the clutch DOES drag, but very lightly and not enough to notice it when applying the brakes while driving.
No biggie right, since I got my Fiero slave creation thing going? Well, I went to install the Fiero slave and this requires me to cut the stock stainless steel braided line. Only to find out the freakin line isn't a -3AN or -4AN. WTF?! So I couldn't get the -3AN hose end fitting on the hose because the Ferrule is too small. Turns out the ID of a -3AN hose is .13x" and the ID of the stock clutch hose is .18x". -4AN is .22x" ARHG!
Anywho, I have the adapter I posted earlier (see post #21) and a 24" -3AN stainless steel braided hose on order. Should be here by next weekend. I should've gone this route to begin with. So much easier and a lot less research. And $31 for the line and adapter. Lessons learned I guess.
Cutting down the T-bolt was easier than I thought it'd be. I first tested it's hardness with a hack saw. It didn't even leave a scratch. Then I tried my high speed with a cut off wheel and it cut through it like butter. I squared it up best I could and dressed the cut end up with some scotch brite pads on my high speed (polished it). I took .100" off. Tons of clearance between the PP and fork, more so than with the stock clutch.
Also, a correction to a previous statement I made, the threads to the Fiero slave are M12x1.0 not M10x1.0. On a side note, finding a M12x1.0 Banjo bolt is a pain. And I could only find them at 19+mm long, so I had to cut mine down to fit right. Then the one I ordered didn't come with the crush washers, ugh. It's hard to find good help now days. LOL. I found an assortment of crush washers for banjo bolts in the Dorman Help section of Autozone and got something that I don't think will leak. Fingers crossed.
Here's the clutch that came out. Turns out it had only about 25K miles on it.
I got my parts in last night, installed, beld, and Ops checked it this morning. Good to go me thinks.
Start the car, put shifter in first, tires don't move (still on jacks), engage clutch, tires go, release clutch, tires still moving, apply brakes, tires stop, let off brakes, tires move a little bit, apply brakes, tires stop, let off brakes, tires stay stopped. So it does take a little bit (inertia??) to get a full disconnect between the flywheel and clutch disc (5 seconds maybe), but they do completely disconnect. I'm happy with this result.
The brass washers I used for the Banjo bolt failed miserably though, They leaked bad with out any pressure on them. I found some 7/16" o-ringed washers when I ordered my clutch line and adapter, so I'm glad I bought those too. No leaks now.
You might want to wrap the braided line with some heat wrap where it is close to the header
Good idea. I did use DOT4 this time.
Test drive went good. This thing GRABS!!!!! It's gonna take some getting used too for sure. The slip point on this clutch is very small. It'll chirp the tires at 1500rpm! Launching with this clutch will be harder for sure.
I did a launch and at 1500 it chriped, grabbed, bogged a bit, then went and at 3500rpm the tires broke loose again and spun through first, barked 2nd, then chirped third. It never did that with the McLeod Dual Friction I had (chirping third).
Driving nice will be a challenge. You feel all the torque of the engine now, at all rpms, even while slipping the clutch. It just wants to go and you feel it. And since these aren't sprung discs, there's no give either.
I must say, I'm very impressed with the grip this clutch has. But getting used to driving it with my power band will be tricky. I definitely need to get the rear axle replaced very soon.
My truck is gone to my brother, so this is my daily again. In a month or two I'll be picking up another car. I'm thinking an Accord or Saturn wagon would be nice to have. Or, dare I say, a minivan! Lol. The wife said no to the minivan, so probably a Suburban. In the mean time, I'll be driving this beast.
But first I need to find out why my fans are blowing the relay fuse now. Ugh. Hopefully it's something simple.
So it does take a little bit (inertia??) to get a full disconnect between the flywheel and clutch disc (5 seconds maybe), but they do completely disconnect. I'm happy with this result.
Have you increased RPM while the clutch is engaged to see if the wheels start turning again?
Have you increased RPM while the clutch is engaged to see if the wheels start turning again?
Engaged? They should (and do).
Disengaged? Yes. They kind of do. I never tried this with any of the old clutches. But understanding how the clutches work, I'd imagine they all do this to a point. The disc is floating between the flywheel and the PP, so with it disengaged and the wheels allowed to free spin, the little bit of interference you'll get from the disc floating around and touching the FW/PP will make the tires spin as you increase the power to the FW. Being that it doesn't do it at idle tells me that it's not a lot of contact.
I applied the brakes and with the Clutch released (disengaged) and the transmission in 1st, then revved the engine a few times to see if I could smell burning clutch, no smell.
I figured out the cooling fans, my O2 extensions were on the long side and I had forgotten to zip tie them back up after the Clutch swap. Opps. They were dragging on the ground and had worn through the insulation. They were shorting out and are apparently fed off the Cooling Fan Relay fuse. I wanted to shorten them anyway, so they are shortened now. All is good.
04-17-2016, 04:27 PM
