conversion to hydraulic clutch

[safe]

I'm fitting a G50 in my car, so along with that I'm converting to an hydraulic clutch.

With limited funds at the moment (and lack of parts to buy), I decided to convert the old pedal assembly rather than by from av 87-88 car.
It's tight but I think I have managed it, one question remains.

The wire operated clutch has a helper spring in the pedal box. Not sure if it's really a helper spring, its quite weak, more something to take out any slop I guess. Right?

Do I need that spring with the hydraulic clutch? Does the 87-88 pedalbox have a spring that pushes on the clutch pedal?

[john walker's workshop]

Somewhere online I've seen a lever system someone made to convert the hydraulic to cable operated. Replaces the slave cylinder.

[vintagecarlover]

Subscribed Hey john. Was it selling the system or show how to?

[john walker's workshop]

It was a picture of the mechanism. Shouldn't be too hard to fab up. Just a bracket holding a lever, bolted to where the slave was, that pushes a rod into the t/o arm on one end and the cable attaches to the other end. The cable was routed up over the side cover. The arm obviously needs to be longer on the cable side for decent leverage, kind of like a brake pedal. Wish I had saved the pic.

[safe]

I have now installed the clutch cylinders and blead them.

But the clutch won't disengage completely, it's just hanging on slightly, enough so I can't get it into gear.
Not sure I have 100% travel of the clutch arm. The slave cylinder push the clutch fork about 15 mm, shouldn't that be enough to release the clutch disc.??

[john walker's workshop]

Is there any freeplay in the pedal? Slop there will mess things up.

[chris_seven]

You will need a minimum of 1/16" (1.6mm) of free play between the clutch pedal and master cylinder or all of the fluid will not return and the clutch won't disengage. As the fluid warms up the drag will increase making the problem worse. If you use an AP Racing Master Cylinder you can shim the 'cut off' and possibly reduce this distance.

You will also need a spring to ensure the that release bearing is kept in constant motion when the engine is running or the constant 'start and stop' of the bearing will cause skidding and premature wear.

Old fashioned Carbon Faced thrusts need to be disengaged but this is not true of ball bearings.

[safe]

I have some free play / slop at the master cylinder (from a 993). Also the spring at the pedal cluster keeps pretension

But I have now eliminated the whole hydralic system.
I fabricated a plate with a long screw to act as a slave cylinder so I could simulate the clutch. Turns out I can never get it to release completely and when I get to 17-18 mm it locks up again. When trying this on a 964 rs engine / gearbox we have in the garage, it completely disengage the clutch at 11 mm.

Also my mm measurements are movement of the slave cylinder.

So I think I have a problem with the parts, which are:
964 engine
911 3.2 g50
964 rs flywheel
964 rs clutch disk
964 rs throwout bearing.
964 rs guide tube.
964 non-rs pressure plate.

I thought that the pressure plate was the same, at least the dimensions, between rs and non rs. Maybe I was wrong?

[safe]

Yanked the engine/gearbox and found the problem....

The clutch disc touched the guide tube of the gear box, just slightly. Not sure if I put the clutch disc the wrong way in...
Should it be oriented as on the 915 with the longer part of the splines towards the PP or the other way towards the flywheel?

Anyway they touched and friction welded themselves together, that ripped the guidetube from the gearbox... So now I have to get the case welded and machined to fix it...

[KTL]

Magnus,

The G50 trans against a 3.6 swap that I did has the clutch damper facing backwards & it used a 993 RS guide tube with longer reach. I've only done one of these installations, around 11 years ago, so me no expert whatsoever!

The parts collection I was involved with consisted of:


968 release bearing = 944.116.080.01
928 flywheel bolts = 928.102.151.01, quantity 9
conversion flywheel = 964.102.239.31 (this is an actual Porsche part number, not an aftermarket specialty flywheel)
Flywheel pilot bearing = SKF# 181799, 6202-2RSJ (I think this is a std. G50 pilot bearing?)
993 RS Guide tube = 950.116.813.30 = a little bit longer than a regular 87-98 G50 guide tube
Ring gear from 964 dual mass flywheel assembly = 964.114.143.31
964 clutch disc = 964.116.011.61 = Sachs p/n = 1 878 000 802 (installed backwards)
LW Clutch housing/pressure plate = 964.116.028.90 = Sachs p/n = 3082 213 133

You also need the original 87-89 G50 ring gear from atop the original clutch housing, longer allen screws to mount the clutch housing onto the flywheel and 27 M8 washers (or 9 nicely machined spacers the thickness of 3 M8 washers

The order of assembly is:

Flywheel, clutch disc installed backwards of normal, new ring gear, Pressure plate, 3 washers, New ring gear, longer bolts through all. The new ring gear is only used as a spacer and is sandwiched between the flywheel and the clutch.

So I imagine a ring of the proper thickness could be substituted for the extra Porsche ring gear

[Tremelune]

Is there any documentation of how you got the G50 in in the first place?

[safe]

Thanks Kevin, for confirming the backwards clutch plate theory.
The other stuff I have, including a custom spacer between the Pp and extra ring gear.

[safe]

Originally Posted by Tremelune

Is there any documentation of how you got the G50 in in the first place?

Not really. Lots of cutting, welding and BFH-ing.