Length comparison 915-shortnose G50

[Wally]

Originally Posted by Steve C

Hi Wally

I was going to use a Saab throughout bearing until I went full G50 clutch.

Steve

Hello Steve,

Nice parts! Why did you come up with the saab TO bearing originally? Does it fit over the original G50 bearing release shaft in the G50 bell-housing (inner diameter sufficient)?

How high is it from the ground up fully compressed and fully elongated?

Thanks in advance,
Walter

[Wally]

The type 4 case with crank and flywheel (with inserted bearing) fits like a glove to the G50





Even the main shaft fits perfectly inside the flywheel nose bearing (411/412 bearing):



So, if I shorten the bell housing and output shaft exactly the same for both, it should work.

[Wally]

Hi Steve,

I will go full VW clutch probably. I found a Luk hydraulic one from a VW/Audi that is lower than the Saab unit, which I also found. The Saab one can be shortenend some and is nicer though.

This is what I'll use as a pressure plate:



The tranny is almost dismantled:

[Steve C]

Hi Wally

Looks good, I didn't get a chance to get back to you with the dimensions, then the forum was down, look like you have it sorted.

I even thought about using the stock G50 fork and making it a push rather than a pull clutch.

Steve

[Wally]

Originally Posted by Steve C

Hi Wally

Looks good, I didn't get a chance to get back to you with the dimensions, then the forum was down, look like you have it sorted.

I even thought about using the stock G50 fork and making it a push rather than a pull clutch.

Steve

Thanks Steve. Well, not sorted all yet, I am close, but not there yet wrt the min. height of the hydr. bearing. Your idea of maybe using it as a push type release may just be another good idea of you

Lee and Rich had another great idea as they told me that the front output shafts of the 4 wheel drive 964 (G64 tranny) fitted the G50 and were 100mm (944/T2 size)! So. if that works out, my problem of the axles looks almost solved :-))

[Wally]

Ok, further removal of all parts in order to be able to machine the housing and main shaft:





Taking the diff out:








Made an adapter plate to mount the Saab bearing onto. The TO bearing itself isn't shortenend yet:

[Wally]

Not sure anyone is still looking at all these weird complicated parts, but this is the clutch plate I'll be using:

[Clatter]

Not sure anyone is still looking at all these weird complicated parts, but

Dude, total car porn... i think I'm in love.

That last pic with the disk, that's a Kennedy from the box in the background?
Always thought you had to go solid center at a big power level... guess not!

Keep it coming!
Can't wait to see how the annular throwout works for you.
Here i am struggling with making a 'slave saver' to keep a regular piston slave from binding...
You ever have binding problems on your current 915 slave setup?

[ricola]

Keep it coming Wally, my favourite thread on here at the moment!
Rich

[Wally]

Thanks for the feedback Clatter, Rich

Originally Posted by Clatter

That last pic with the disk, that's a Kennedy from the box in the background?
Always thought you had to go solid center at a big power level... guess not!

Yes, it comes from that box.
Well, I recently read a leaflet from Sachs where they explained the differences in clutch plate style. Was very informative and sort of opend my eyes as I never really understood what was what with all the availabkle clutches in the type 1 world.
Fact is that a solid center can indeed hold more torque. A 4 or 6-puck 'metallic' plate style can hold more torque than an organic disk. But...my own perception is that the diameter of the clutch has a large part in this as well. The type 1 guys always only work with 200mm, so you never hear about them using the diameter of the disk in the equesion. With that limited 200mm diameter, the organic disks have their limits for sure. Thats usually when 'they' step up to x-puck (semi)metallic disks and experience the on/off engagement of the metallic disks...

My own experience was that I could launch my 2200 lbs fat chick with me in it on full M&H drag slicks with 345Nm (255 ft lbs) on a stock 225mm (=organic) spring centered disk and stock 915 (old too) PP. Once I had the right leverage figured out on my tranny's clutch arm, I had a very acceptable pedal force and excellent progressive clutch grip.
So since I had not found any limits yet on the organic disk of that (similar) size, i hope with the special KEP plate and the HD Sachs PP that I can stretch the limits somewhat further and still enjoy the easy engagement of the organic disk.
After all, its a street car that drives on its own wheels to circuits and drag strips.
If the organic disk will not hold what I am making now, there is also a 6-puck spring centered disk from KEP in the same dimensions and same G50 center
Even nicer wrt engagement and capable of transmitting huge torque is a two-disk set-up (with organic disks), but that involves a lot, so not yet neccesary

Can't wait to see how the annular throwout works for you.

You ever have binding problems on your current 915 slave setup?

Me too, but I still have not found enough room for the current ones I have, so nothing certain yet I can use an annular one...

As I wrote before, the right leverage of the arm is critical, so I would adjust that if at all possible to gain the right amount of throw of the TO bearing, which will prevent binding too. My SACO set with the CNC (its a mark) slave had enough trow in the end I found out. I needed to adjust and adapt quite some untill it was working as well as it finally did last year. Correctly bleeding the set-up is important too...
There are some old posts by Shad Laws where he writes about his Saco set and his 923 (basically a 915) tranny set-up. Maybe that helps some too.

[Steve C]

Hi Wally

Love reading this thread.

I believe that the sprung centre will also prevent some nasty harmonics on deceleration.

Steve

[Wally]

We did a lot today. A friend helped out machining down the bellhousing, nachined the bellhousing a tad bit wider afterwards so a type 4 fits again flawlessly on the bellhousing and shortenend the hardenend splines on the main shaft:

Before:

After:




Case fits fine now:



Result is super! I only need to shorten the shaft myself now but that is not a problem.

Thanks John! :respect:

[Xellex]

extremely interesting thread! Keep going at it, and keep the pics coming!

[MX67]

Crazy freak! Keep on!

This is first time that I can see difference between G50 and 915...

Thanks for informing us with all this stuff! 8)

[Wally]

Right, a lot has happenend since the last post.
Time for an update!

I got the transmission back together again!


The hydraulic VW/Audi (Luk) TO bearing has been used and mounted directly onto - or should I better say INto - the tranny casing (drill and tap 3x M6). Engagement of the clutch is VERY light, much lighter than the way I had the 915 converted with a hydraulic slave cylinder that worked on an arm an lever to engage.

Another thing to modify is provisions for the starter motor. After some measurements and looking at 964 starters (way different, I even bought one I can't use), I decided to try a 091 starter from a late bus. Its about 8mm longer and I need the extra length. I actually need 16mm more length, but that doesn't exist, so the CNC wizzerd machined the starter motor opening down some 8mm:


It turned out that the original VW ring gear is NOT exactly the same diameter. Its about 3mm in radius smaller than the porsche. Who knew this huh? In hindside I better would have Kennedy make me a new chr-mo flywheel with the right 3,2 '87-'89 ring gear diameter, but for now I elongated the south hole of the starter itself so the starter rotates more towards the ring gear.
The rear hanger support needed about 2 cm (less than an inch) increasement in length to support the bellhousing being more out to the rear of the car.



After some futile tries with an original 091 starter (bearing supported end), I ordered a Hi-torque from John at Powerhaus at a smacking price and super swift shipping and that works awesome. I have started a lot lately and it doesnt move or grind and turns the engine very quickly, so that works now!