Necessary clutch movement?
05-04-2016, 09:47 PM
#1
Necessary clutch movement? Hi All,
Building an LS3 ahead of a Jerico 4 speed, old-school BBC scattershield, Spec stage 2 clutch, and Howe hydraulic t/o bearing. Even though my M/C allows for 1 1/8" stroke, due to floorboard constraints I can only get 0.960". This gives me ~ 0.450" total movement at the clutch. Think that'll be enough? I'd hate to have to cut out the floorboards to gain a little more pedal...
Building an LS3 ahead of a Jerico 4 speed, old-school BBC scattershield, Spec stage 2 clutch, and Howe hydraulic t/o bearing. Even though my M/C allows for 1 1/8" stroke, due to floorboard constraints I can only get 0.960". This gives me ~ 0.450" total movement at the clutch. Think that'll be enough? I'd hate to have to cut out the floorboards to gain a little more pedal...
05-05-2016, 09:00 AM
#2
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Full stroke on GM slave is only 0.5", and the stock master doesn't push it that far at all.
If you get a larger bore master, you can get by with a shorter stroke instead of cutting the metal. 7/8 vs 3/4 would do it
If you get a larger bore master, you can get by with a shorter stroke instead of cutting the metal. 7/8 vs 3/4 would do it
05-05-2016, 12:23 PM
#3
Right, that's common knowledge. Was hoping to hear what the actual stroke required to disengage the (diaphragm) clutch would be. Howe's instructions say to shim their t/o bearing into a very light preload, so all pedal movement should be transferred. I'll be mocking it up soon, just don't don't like unplanned-for surprises...
05-05-2016, 01:34 PM
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Ok gotcha. Here's how mine measured out.
I had .115 between the fully collapsed TOB and the PP fingers. At full disengagement I got 11mm best guess (no direct line of sight) from the various angles I could try to get. Don't ask.
So .115 is just short of 3mm. 11 mm is about .440". So, the slave moved a total of .440, and the first .115 was taking up slack. Leaves .325 to actually work the clutch.
That help?
I had .115 between the fully collapsed TOB and the PP fingers. At full disengagement I got 11mm best guess (no direct line of sight) from the various angles I could try to get. Don't ask.
So .115 is just short of 3mm. 11 mm is about .440". So, the slave moved a total of .440, and the first .115 was taking up slack. Leaves .325 to actually work the clutch.
That help?
05-05-2016, 01:58 PM
#5
Absolutely! Those number leave me some slack, therefore, I think I'll shim for some clearance so the fingers can extend out as the disc wears. I know Howe is used to setting these up for racing, where the clutch gets checked each race. I'd rather have that "take up slack" so I'm not pulling this out every couple months to re-shim...
05-05-2016, 02:07 PM
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There's a sticky I think on measuring for clearance and clutch shims. Follow it, but make sure you're doing the TOB fully collapsed. Then, once you know the travel needed for the clutch, make sure the gap plus travel is less than 460, and that should give you room to wear