docmirror

Ok, I didn't know the shafts were hollow, thus, I guess you would use a shear. For a solid bar, it would be Youngs I guess.

76FJ55

Actually the shaft is solid, but it may be easier to envision an infinite series of thin walled tubes stacked inside each other. at any radius you will have a thin walled tube which can be used to see that a unit at that radius is again in shear. This uses the principal of superposition to combine all the shells to form the completer solid bar. For item being twisted you will use the shear modulus. the value of J is determined by the shape and relative location of the axis. for instance a hollow tube with a central axis will have a J value = Pi/2*(R^4-r^4) where R= OD and r=ID. from this you can see that J for a solid round is actually just the simplification of the previous equation where r=0.

docmirror

Ok, obviously materials was a long time ago for me. I would have used Youngs and got it wrong, sigh......

m4martin

Hi All,
Just an update, i have removed the S4 engine now, what a job! Having inspected the Crank and Block the best description i can say is it's not a sight any of you want to see in your own engine. The crank counterbalance weights have been hitting the block on all internal forward faces. Two of the block main housings are cracked, The block has been scored by bearings spinning in their housings, the thrust bearing has made a mess of the block and crank. The crank has got so hot on some faces it has blued with heat. To fix it we would need to weld the block, line bore, hone. Possibly straighten the crank, regrind, and fit oversize bearings. The thrust faces would need re-metaling. The crank would need re-balancing, the engine stripped, and inspected for bore and piston damage too.

So, for a quick check on the coupling clamp, was it all worth it?? I know my view!

Also, what were Porsche thinking when they designed that stupid little hole in the bulkhead, and a huge wiring harness, with no plug and socket at the bulkhead. We just need to pass the harness plugs through. Sometimes the level of stupidity amazes me!!!!! I can't wait for the job of transferring it all to another engine, and refitting the wiring in the footwell !

I AM going to enjoy a drive in this car, i am determined!!

Black Sea RD

Hi Martin,

Very sorrry to hear about the state of your engine but it was fully expected.

TBF really causes a mess in the engine, especially when the engine is at the point of being seized up.

Best to you on your engine rebuild! Keep us informed and ask questions!

Good luck,

DonS

A description like this needs pics! Thanks again for the thread...

m4martin

I will try and get some photos soon, but the car and engine is in a friends workshop.
Also, i have to lift the engine on a crane now, to get photos from underneath.
The engine is only taken apart from below, as i may need to leave all components attached for an exchange engine. I am now trying to find an exchange engine, which in the UK seem few and far between.
I will get you photos as soon as i can.

dcrasta

Im curious,

If a poll was taken how many TBF's are also cars with dead/collapsed motor mounts.

I have a deadly sounding rattling coming from under the car, and Im scared of it. Im parking the car until I figure it out.

But, I also was 'speculating' about the following ..

If the motor mounts collapse, is the resulting difference in 'angle' between the front couplers and the rear coupler enough to cause increased mechanical stress on the torque tube, and cause bearing damage, eventual TBF failure? Seems to me this design would be dependent on the driveline angles being as close as possible, as all the 'articulation' isolated from the driveshaft (where 'normal' cars have a Driveshaft with Ujoints that allow some 'articulation' of the driveline..

Just speculation. Anyone have any arguments or additional info? (yes I searched all the existing threads and I dont intend to Hijack, do we really need another TBF thread today? )

blown 87

They are all bolted together as a unit, it would have to bend the TT to do that, so no is the answer to your question about the mounts.

dcrasta

Drat Greg pissing in my cornflakes! (back to the 'theory' board..)

blown 87

Why dont you just check the end play, not much to it.
They can make some noise when the mounts are done.

James Bailey

Often noises under the car automatics will be bad torque tube bearings ...they hum ,then whine, then rattle, then bang, as it progresses

86'928S MeteorGrey

Or the torque converter support bearings.....Or BOTH...

I suggest a stethescope to determine where the sound is coming from, as the driveline setup transmits sound making it hard to pinpoint. Good luck!

dcrasta

Thats how I plan to spend my 4th. Actually its a Motor-Barbecue

I will be -
checking endplay
Checking front and rear flexplates
Re-torquing the clamps with Loctite (Blue)
Installing my JagerMount (temp fix for now)
Changing oil (and saving a sample for analysis)
Replacing all the vacuum lines.

Hope I can knock it all out tomorrow (Friday)..

plan to set up the grill so I can have some friends around me when Im under the car..



(Oh I was just joking about the cornflakes..)

And after all that I could be looking to rebuild the Torque Tube, but before I spend Torque Tube $$ I will definitely be checking endplay.