Made some progress over the past week or so.
I installed the last-2 diagonal braces:
And started working on shortening the 924 torque tube. I took lots of pictures to document the process since there seems to be quite a bit of interest/discussion about it from the 924 and VW guys(who are interested in doing a RWD conversion on a VW FOX), yet there's no documentation that it's ever been done before. This way I can reference those folks back here to this thread.
First, here's what the torque tube looks like. The big housing is the input housing fo the rear-mounted transaxel....it's supposed to just slide freely on the tube, but mine is completely siezed in place.
The length of the housing is just over 69"....
...unfortunately, the cockpit of my book-sized frame is just over 54"
The way the torque tube is made has a space of about a foot from the input flange, up to the first bearing.
There's also about 4.5" from the rear end of the tube up to the rear-most bearing.
I was originally considering shortening both the front and rear of the tube, for a total of ~16" reduction in length...and I may still need to(I won't know for certain until I have the engine/bellhousing/tube/trans all mocked up into place), that would have put the bellhousing right in the same location as a normal transmission & still left the rear mounted transaxel in the correct place. But since I'm using the VW 1.8L which is only 18" long from the front of the pulley to the rear of the crank, and the 924 bellhousing is only 6" long, I think I'll be OK just shortening the torque tube by the 12" on the front. Yes, that will put the weight of the engine more towards the front - but w/the rear mounted transaxel my weight bias will likely be skewed toward the rear anyway. And yes, that will give me a higher polar-moment than a *normal* locost....but such is the price I pay for being a cheap-skate.
But at least I'll have wide footwells if this works out!
Anyway, I started by grinding out the weld for the front mounting flange. Once I got to the point it was cracking, I just used a BFH for final removal.
It's hard to tell from this pic, but the weld penetrated far enough into the plate that there was a ridge that needed removed.
From the front side it was apparent that the plate wasn't welded fully through, so I made a couple trial cuts w/a hacksaw to determine how deep the welds were.
From there, I used my angle-grinder to remove metal from the back side until the weld was removed.
This shows the first bearing inside the tube. The 924 uses a pilot bearing for the shaft which would explain why this bearing is so far back.
I used a pair of hose clamps & my scribe to mark a circle for the cut.
The angle-grinder cut right through the tube & was right on target.
I again used the angle-grinder...at an angle...to cut through the shaft. I was surprised at how soft the shaft was - I cut right through in ~30-seconds. I actually cut off 3-pieces: the front splined section & 2-other pieces to practice rewelding them back together.
I talked to about a dozen people about what would be the best way to shorten the shaft. The general opinion was there are 3-ways: I could cut it off & respline it...but I'm not equiped to cut splines & didn't want to have to find/pay a shop to do it. I could cut both ends to a taper & reweld. Or I could sleeve the shaft w/a tube & weld it on. I chose to do both of the last-2. First I clamped the shaft together w/a piece of angle iron.
Then welded(this was after the first pass, I went back around & re-welded, then ground down the welds).
I was fortunate that the same tubing I used for the front diagonal braces also had the perfect I.D. to sleeve the shaft. After the sleeve was fully welded, I once again ground down the welds at both ends to smooth/balance the shaft.
I was a bit surprised by how true it ended up. I used the grinder to spin the shaft up to speed & didn't notice any vibration. There is a very slight visual wobble at the very end, but with the clutch disk installed, there isn't any eccentric movement of it. I also plan to take the tube over to a friend's this week to use his torch to try & remove the tail housing, so I'll just heat the shaft a bit & try to shrink it into alignment while I'm there.
The last task was to weld the front flange back into its new location. I used a square, level, and hammer to tap it on in the correct position. I then tacked it into place on 4-sides to keep it square before welding it fully.
Honestly, I was a bit surprised at how easy a task this was & I'm surprised that no one else has documented this before.....of course, it's going to be a long time before I ever get to find out if it's actually going to hold together & work!