Jack Rabbit Clutch

[jimuris]

I an installing these clutch discs in my 24 transmission small brake drum. The instructions say I might have to add 2 extra discs. Is that for a 26,27 large brake drum only. I want to make sure before putting this together.

[speedytinc]

I an installing these clutch discs in my 24 transmission small brake drum. The instructions say I might have to add 2 extra discs. Is that for a 26,27 large brake drum only. I want to make sure before putting this together.

Both drums take the same # of disks.
An extra large disk or 2 will take up extra space to give more finger set screw adjustment if needed in the future.

[Craig Leach]

Hi James,
There is a clutch pack total thickness dimension that should be easy to find online. To thick will reduce the disc gap
when the clutch released & to thin will reduce the spring pressure. The clutch the fingers have a limited leverage ratio
so try to stay as close to the spec thickness as you can. Many have stated that & I believe the service manual states the
clutch spring should be @ 3" with the clutch release to cover @ 13/16". With a Turbo 400, jackrabbit or a watts clutch
I would error on the thick side as opposed to the thin side.
Craig.

[Kerry]

Spring is 2"

[Mark Gregush]

I shoot for around 100 LBS compression at 2 inches for the spring before assembling the transmission then adjust to the 13/16" when assembled as a starting point. The clutch disk pack should be about 1 1/8" tall.

[speedytinc]

With a th400 clutch, I really insure a tight lock up with a new heavier spring(110-120#) & another 1/2 turn tight from the 13/16" setting.
Remember the stock steel clutch has some controlled slip by design. You want ZERO slip with a 400 clutch.
Follow the installation directions & make sure your linkages are set properly.
These clutches fail from mechanic/operator error.

[jimuris]

Thanks to all, that makes a lot of sence.