Dual Disk Clutches

[The Dark Side of Will]

Gotcha.

So you are saying you can get a round faced tob and modify for the getrag fingers?

Did you look at the Summit link I posted above? That shows the actual bearing.

With that, I just need a holder that holds that bearing and drops onto the Getrag throw out sleeve and works with the Getrag throw out fingers

[The Dark Side of Will]

Now for an HTOB Getrag, it's probably more feasible to adapt a Tilton HTOB... that *might* be as simple as a 1/4" thick laser cut adapter plate.

[The Dark Side of Will]

This is what happens when a stock type throw out bearing operates one of these clutches:



Here's an LS4 flexplate. The largest footprint of a button flywheel that can bolt down on top of the crank pattern is about 4.125" diameter. It sure looks like the TIlton button is larger than that at the crank flange.

[Shaun41178(2)]

Is that quatermastwr pressure plate still available for purchase?

[ericjon262]

This is what happens when a stock type throw out bearing operates one of these clutches:

I'd also bet it becomes much harder to operate with any finesse like that...

[The Dark Side of Will]

Is that quatermastwr pressure plate still available for purchase?

I can sell it to you, pending some more discussion with QM...
I strongly advise replacing the spring, for reasons obvious above.

[Shaun41178(2)]

Yea I meant if you knew if QM still had a lot of these parts still available for purchase new.

I want a twin but also want to be able to get replacement parts.

[The Dark Side of Will]

Yes, that's an older model, but QM still has similar models on the market.

[Shaun41178(2)]

I want it but not till a throw out bearing has a solution.

I know wcf claims to have a twin for the getrag but I havent called to ask how they did it

[The Dark Side of Will]

Yea I meant if you knew if QM still had a lot of these parts still available for purchase new.

I want a twin but also want to be able to get replacement parts.

The one pictured is an older version of their Pro Series.
https://www.quartermasterusa.com/qm/clutches/pro-series

[The Dark Side of Will]

The bare Tilton mechanical TOB is PN 62-002-5. Summit carries it.
The journal is presses onto--for example on a BMW or Mustang mechanical TOB assembly--is 1.5752-1.5758 diameter x 0.300 tall.

Tilton rep says they don't sell dual organic disk packs because the disks tend to come in a little thick. That messes with the stack height of the clutch and has given some of their customers release problems from the disks being to thick.

The TOB is 0.730" tall and the OD of its inner sleeve is 1.755".

[The Dark Side of Will]

The 282 mechanical throw out sleeve that's part of the input bearing is 1.755" long.

I have one more measurement to make, but I don't have a long enough straight edge for it right now

[The Dark Side of Will]

The overall height of the unit isn't final, but here's the first take:



The slots in the small end are there to allow puller jaws to get behind the race of the Tilton TOB if it comes apart from pulling on the sheet metal shroud.

The locations where the throw out fork fingers land on the stock TOB holder get worn by the fingers. Obviously there's friction there. I'm thinking that if there's enough clearance at the final height, I may put small sealed ball bearings on the sides of the TOB holder in order to eliminate that friction, especially in light of the fact that the throw out load will at least double.

ETA: also using rolling element bearings at the throw out fork interface is that the entire part can be made of aluminum in that case. With the throw out fork fingers directly acting against the holder, the part has to be made of steel.

[The Dark Side of Will]

I just had a DUH moment... if I can't find the right diameter master/slave cylinder combo, I can build (or even buy?) a compact pressure intensifier to install between the stock cylinders to adapt the hydraulic ratio to work.

Of course that's probably MORE work than just building a large diameter slave, but I don't think I'll be able effectively to build a large area slave for the HTOB transmissions.

ETA: With a little more thought... Since all the production clutches use similar throw out load/distance numbers, *ONE* pressure intensifier design would cover pretty much all the FWD Tilton swap applications, and I wouldn't have to reinvent the wheel to go from external mechanical throw out Getrag to internal mechanical throw out Getrag to HTOB Getrag to F23 to F40 (as well the Muncie and Isuzu units for people interested in those boxes)

[Shaun41178(2)]

Progress?

[The Dark Side of Will]

Working on the TOB, which is a fairly intricate, fussy, annoying, finnicky part to package, even once the basic specs are determined.

I think because of the extra throw out load on the stock fingers, I'm going to have Calico DLC coat the area of the part that the throw out fingers push on.

The OD of the TOB guide shell that's made into the input shaft bearing is 30mm. Finding plain and flanged plastic bushings for 30mm shafts is at least not difficult, so I don't have to MAKE a bushing. If you look at the stock Getrag TOB holder, the center shell that rides on the throw out bearing guide is actually plastic. I only realized that within the last year or two. It actually doesn't need any kind of grease at all. Naturally, mine is following the same paradigm.

Also, if I can get it to clear the Northstar water log, per Steven's numbers in this thread: viewtopic.php?f=3&t=2986
I may be able to use the cast Muncie/Isuzu throw out arm with the Getrag slave cylinder in order to have enough mechanical advantage to have a reasonable pedal effort.

[The Dark Side of Will]

There are still plenty of detail changes left, but this is what it's actually going to look like:

[Shaun41178(2)]

Why are you so concerned with pedal effort? Do you think your leg wont handle it? Is it a concern with the seals in the master and slave blowing out?

I use the Isuzu slave with my getrag. I dont know what that does for pedal preasure. Its still a light pedal though in my opinion.

I would think the pressure plate and how stiff the fingers are and clamping load would have a larger effect on pedal effort than anything else.

Maybe I am wrong?

So I had my pp modified for more clamping force. From lime 1600 to 2200. My pedal still feels light

Getting a twin in this thing is gonna be needed.

[The Dark Side of Will]

I've had a bent clutch pedal before... Fiero have a tendency to do that. Yes, it was the steel one. I also want this car to be a three season daily and there's traffic in the DC area.

Pedal load is a number. You wrote a post about pedal load with no numbers for pedal load. If you were trying to make a point, you didn't.

[Shaun41178(2)]

Weld a gusset on your pedal?