Two slaves back to back, Yet another hydraulic clutch tweek...... Options

[drive-ability]

I have had my clutch working now for some time but have had trouble with my slave cylinders. They would be fine but leak a bit because they would be maxed out all the time. I had been thinking of using 2 back to back for a while and have had them on for a while. Well they hold together better than one. The old setup would use 99% of the travel and just put too much pressure on the units. They would almost always leak a bit. Now with two there in there sweet spot and hopefully wont leak. I was able to join them together and bleed them quite easily. Time will tell.

(IMG:http://members.cox.net/stdotjohn/CIMG3005.jpg.600.jpg)

[sj914]

That looks like an interesting setup. What size master do you have at the pedal?

[drive-ability]

That looks like an interesting setup. What size master do you have at the pedal?

The master is 1 - 1/8, Ya a big one. It pushes a lot of fluid, quick. I had to make the pedal unit. The standard 6-8 to one ratio just didn't have enough leverage. I have enough transferable fluid to increase the fork length to ease the pedal tension. Using a stage 2 PP makes a hard pedal without going through a lot of experimentation. This is likely the one of a dozen different tweaks along the way.

[rick 918-S]

interesting. (IMG:style_emoticons/default/idea.gif)

[Twystd1]

I have some news for you.

The TILTON hydraulic T/O bearing has been used in your 930 transmission before.

I imagine that would alleviate much of the headache you are havimg with the heavy pedal issue.

I found 2 references so far. No pics yet.
I just googled "930 + hydraulic throw"

Been perusing ever since.

That may be a good option for you.

I know WEVO makes em for the 915 and 901. Ya might want to give them a call.

Clayton

[dakotaewing]

Clayton -
My BIL runs with the cobra crowd, and they have some of the same issues that drive-ability is dealing with... One of the options that they have is the hydraulic T/O bearing as you suggested... But, most of those guys avoid the hydraulic T/O bearing due to failures, and once it goes you have to pull the tranny, and in some cases replace the clutch due to fluid saturation.
Mind you, I don't know anything about Tilton T/O bearing, just stating what I have heard about the H T/O B's in general...

Thom

[aircooledboy]

(IMG:style_emoticons/default/piratenanner.gif)
Hey Drive,
Sorry for the hijack, but I've gotta ask. Looking at your videos on youtube, it certainly sounds like you got a serious reduction in volume when switched to the Ferrari mufflers. I've got the mufflers, but before I go thru the hassle of fab'ing up hangers, pipes etc., was it worth it? (IMG:style_emoticons/default/idea.gif)
I would really like to quite down the sled at idle.

[andys]

Down side of the hydraulic (TOB) T/O bearing (the kind that mounts on the input shaft tube), is that there's no external adjustability w/o pulling the trans. They also seem prone to failure; this seems odd, as you'd think this is mature technology, but they just don't seem to last (for a non-racing application). BTW, doesn't the late model Camaro (98-02) use a pull type slave? Perhaps there's a cheap retrofit opportunity there?

Modern cars have a forward biasing clutch slave, so no adjustment is required, and it automatically keeps the pedal up. In those examples, the TOB is designed to ride against the fingers of the PP. I don't think this is possible with a TOB not designed for this configuration. In my particular caes, I despirately wanted to run a forward biased slave, but I have a QuarterMaster clutch with a traditional radiused face. They advised me that I may get pre-mature wear of the PP fingers if I go forward biased.

Andys

[drive-ability]

(IMG:style_emoticons/default/piratenanner.gif)
Hey Drive,
Sorry for the hijack, but I've gotta ask. Looking at your videos on youtube, it certainly sounds like you got a serious reduction in volume when switched to the Ferrari mufflers. I've got the mufflers, but before I go thru the hassle of fab'ing up hangers, pipes etc., was it worth it? (IMG:style_emoticons/default/idea.gif)
I would really like to quite down the sled at idle.

I love the mufflers, there the only ones I will run, they are reasonable quiet at idle and cruse, or have a big deep sound when the valves are opened. I wouldn't give them up for anything.

[drive-ability]

I have some news for you.

The TILTON hydraulic T/O bearing has been used in your 930 transmission before.

I imagine that would alleviate much of the headache you are havimg with the heavy pedal issue.

I found 2 references so far. No pics yet.
I just googled "930 + hydraulic throw"

Been perusing ever since.

That may be a good option for you.

I know WEVO makes em for the 915 and 901. Ya might want to give them a call.

Clayton

Hey Clayton,
That sounds cool, just as we get some info we find they may be unreliable! I will do some Googling and see what comes up..
John

[DBCooper]

Don't worry too much about reliability, they've been standard equipment on all Saabs since the 80's. They go well over 100k in those cars, just about the same as the brake hydraulics. Change the fluid, just like brakes. I've only had one new one that leaked, and that was because I tried a cheaper (damn) aftermarket unit. I'd worry more about that back-to-back setup you have. You've reduced the stroke of each, good, but you've doubled the number of seals in line and there hasn't been any reduction of pressure on the fork, so double the trouble.

One real nice thing about the hydraulic units is you get a nice linear pedal feel out of them, so along with being softer it feels lots more precise than a fork lever. Oh, and they shouldn't need any "adjusting" once they've been set up. The fluid takes up any slack that comes from wear, no different than hydraulic brakes.

[drive-ability]

Don't worry too much about reliability, they've been standard equipment on all Saabs since the 80's. They go well over 100k in those cars, just about the same as the brake hydraulics. Change the fluid, just like brakes. I've only had one new one that leaked, and that was because I tried a cheaper (damn) aftermarket unit. I'd worry more about that back-to-back setup you have. You've reduced the stroke of each, good, but you've doubled the number of seals in line and there hasn't been any reduction of pressure on the fork, so double the trouble.

One real nice thing about the hydraulic units is you get a nice linear pedal feel out of them, so along with being softer it feels lots more precise than a fork lever. Oh, and they shouldn't need any "adjusting" once they've been set up. The fluid takes up any slack that comes from wear, no different than hydraulic brakes.

The system seems to be working good, using two has placed the pistons in a better place. Now the seals are in the center of the stroke, not the end where they wiggle around and leak. I just give it a tad of free-play to keep the pressure off the T/O bearing and the crank thrust bearings. ...

[byndbad914]

The problem/reason why you can't find a hyd TOB is because they are not "pull-style", they push the forks.

915/930s require a pull style TO, UNLESS you change to a push style pressure plate. Look at most of the kits you see and they always are small diam twin or triple disc setups. Those use push-style pps.

If you want to use a stock design pp you have to pull the TO. As for the 930, you might be able to get a full flywheel/trip disc/hyd TOB setup but that flywheel will bolt to a Porsche crank. Nothing out there yet for a hyd TOB/SBC/930. I have been searching for one for years and nobody is making it.

tilton will make me a setup based on all of my conversion components, but they required both nuts, not just the left one (IMG:style_emoticons/default/sad.gif) I would give my left nut for a lot of things, but both is a different story. (IMG:style_emoticons/default/laugh.gif)

Maybe I need to start a "group buy" thread (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/chairfall.gif) Maybe get a dual disc 7.25" setup for under $3K if I buy one, driveablility, and Bill (3 guys that are not too stoked about their Kennedy Stg IIs). One of us would have to send in the Kennedy flywheel/clutch package so they could reference dimensions, then still have to get some sort of deal like WEVO has that mounts on the stock arm or I have seen a TO/sleeve kit that you remove the slider tube (which I think both Bill and driveability have gone thru at least one of those), bolt on an adapter and TO bearing (see link below)

I called and left a message and have emailed these jackasses and they haven't responded, but that 930 setup they have with the right custom flywheel would work perfectly. If anything maybe they have the 930 TO adapter all worked out.

http://www.jbracing.com/flywheel-porscheul1.php#custom_fw

In any event, getting a good clutch in these combos is going to be serious money IMO. Course I got about $1500 in a rather marginal setup at this point - it has worked fine for me thus far but my left quad is about double the size of my right one (IMG:style_emoticons/default/huh.gif)

[andys]

The problem/reason why you can't find a hyd TOB is because they are not "pull-style", they push the forks.

915/930s require a pull style TO, UNLESS you change to a push style pressure plate. Look at most of the kits you see and they always are small diam twin or triple disc setups. Those use push-style pps.

If you want to use a stock design pp you have to pull the TO. As for the 930, you might be able to get a full flywheel/trip disc/hyd TOB setup but that flywheel will bolt to a Porsche crank. Nothing out there yet for a hyd TOB/SBC/930. I have been searching for one for years and nobody is making it.

tilton will make me a setup based on all of my conversion components, but they required both nuts, not just the left one (IMG:style_emoticons/default/sad.gif) I would give my left nut for a lot of things, but both is a different story. (IMG:style_emoticons/default/laugh.gif)

Maybe I need to start a "group buy" thread (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/chairfall.gif) Maybe get a dual disc 7.25" setup for under $3K if I buy one, driveablility, and Bill (3 guys that are not too stoked about their Kennedy Stg IIs). One of us would have to send in the Kennedy flywheel/clutch package so they could reference dimensions, then still have to get some sort of deal like WEVO has that mounts on the stock arm or I have seen a TO/sleeve kit that you remove the slider tube (which I think both Bill and driveability have gone thru at least one of those), bolt on an adapter and TO bearing (see link below)

I called and left a message and have emailed these jackasses and they haven't responded, but that 930 setup they have with the right custom flywheel would work perfectly. If anything maybe they have the 930 TO adapter all worked out.

http://www.jbracing.com/flywheel-porscheul1.php#custom_fw

In any event, getting a good clutch in these combos is going to be serious money IMO. Course I got about $1500 in a rather marginal setup at this point - it has worked fine for me thus far but my left quad is about double the size of my right one (IMG:style_emoticons/default/huh.gif)

byndbad914,

Have you tried QuarterMaster? Unbelieveably helpful, at least for my custom setup. I used their 8 1/2" Extreme V clutch and button flywheel; they made a custom disc to fit my Getrag input spline and I opted for a spring center. SBC button flywheel and Porsche splined discs should be no problem for them. These guys are real racers and will take the time to discuss your application. This is their busiest time of the year however, so custom work comes after their Nextel Cup/Bush/other racing commitments (it's the start of the racing season).

Down side of multi-disc clutches is usually the lack of room for something like Marcel springs which help tremendously to ease that suddeness typical of race clutches. If you want a race clutch, then it's not an issue.........I think you already know all this stuff.

Andys

[DBCooper]

The problem/reason why you can't find a hyd TOB is because they are not "pull-style", they push the forks.

Wup!! Good point, I'm still thinking 901.