[This message has been edited by Moar (edited 02-29-2016).]

quote Originally posted by Gall757: The images that don't show are over 300K in total size. The horizontal pixel count is 1024 or less, which is what is needed, but the vertical dimension is too long.

My experience when posting images here (I use PIP) is that there is no height restriction with the image. As long as the file size is 300 kb or less and the maximum width is 1024 pixels, you're good to go.

Moar, use a free photo editing program like IrfanView to re-size and/or re-compress your images. I love this program as it allows the maximum file size to be set before you save the re-sized images. (No need to experiment over and over with different compression settings.)

[This message has been edited by Patrick (edited 02-29-2016).]

[This message has been edited by hobbywrench (edited 02-29-2016).]

quote Your father is a lathe operator?

No, it is not his job.
Hi drives trains and big excavators at ÖBB.
But he has access to a lathe at work during the week!

However, we have both sufficient skills to use a lathe.
The problems are the tools.
The repair shop at ÖBB is very old and the tools are old too.
In the past ÖBB has used the shop often for repairing a lot of stuff themselves, but nowadays
almost everything is repaired by service companies instead.
Therefore, nobody at ÖBB buys new lathe tools.

Alternatively we can use a grinding disc from an angle grinder (with about 3 mm thickness).
We must fix this grinding disc somehow on the lathe...
I have calculated a minimum diameter of 24.7 mm for the groove with a big 3 mm radius.
(original diameter is 25.9 mm directly after the spline)

With these groove dimensions the shaft´s fatigue endurance shouldn´t be affected too much.
(but I have not considered the impact of lost surface hardness due to the lathe operation)

Regarding surface harness I´ve found the following hardness depth profiles:

[Induction hardened AISI 1070 steel bars:

The blue curve represents Q&T material, which begins to loose hardness at 0.05” (1.25 mm) below the surface significantly.

Case hardened steel (unknown material):

This case hardened steel begins to loose hardness at about 0.6 mm below the hardened surface.

I only need to remove 0.6 mm radial, therefore I should still have sufficient micro-hardness at this depth.


PS:
Yes, I have used a China diamond grinding bit.

[This message has been edited by Moar (edited 03-03-2016).]

Yes, I know that the c-clip may not hold the shaft very tight in position.
The groove edges in the shaft must be rounded in order to reduce the notch effect.
(circlip groove with sharp edges has a very high notch effect factor of about 2.0!)
Furthermore, the c-clip wire thickness needs to be reduced to 1.00 mm.
The inner diameter of the bore of the differential housing is 27.30 mm.
When c-clip is pressed into the bore the inner diameter of the c-clip will be 25.30 mm (compressed).
The circlip groove inner diameter will be 24.70 mm.
This means the c-clip will have a radial clearance of about 0.3 mm while the shaft is inserted into the diff housing.
Maybe I should grind the c-clip wire thickness down to 1.20 mm instead (more stiffness compared to 1.00 mm).

No, I haven´t ask others so far.
But are there any alternatives to my plan?
What else I could do to hold the shaft in position after the front section of the spline is cutted off

[This message has been edited by Moar (edited 03-01-2016).]

Now it's done!

Finished snap ring groove after fine grinding and polishing (di = 24.90 mm):


Cutted off spline shaft front section:



Modified Fiero c-clip engaged into new custom groove:


The good thing is that one drive shaft (long one, passenger side) is now ready for installation, but the other one (short one, driver side) is messed up!
I don't want to post a picture of the other drive shaft, because the groove is not a small snap ring groove it is more a predetermined breaking point.
My dad is often very imprecise and now he has messed up one of my drive shafts.
The inner diameter of the groove is only 23.07 mm instead of 24.70 - 24.90 mm!
If I would have used the angle grinder for making a groove by myself the diameter would be much more precise. Next time I know.

I´m not motivated to make any calculation for the messed up drive shaft, because I already know that it will break sooner or later anyway (even with stock engine).
(also the passenger side drive shaft with correct groove dimensions may break with the bigger 3.4L engine in conjunction with wider tires after some hard acceleration starts)

A new drive shaft only costs about $25, but shipping costs are nearly $100.-

[This message has been edited by Moar (edited 10-25-2017).]

In the meantime, I have carried out some driveshaft’s calculations.
The maximum transmittable torque of the weakest driveshaft (with the biggest groove) is about 1250 Nm with assumed material 34CrMo4.

I think it is almost impossible to get so much traction that a torque of 1250 Nm is exceeded (per wheel).
Only with wide tires on dry concrete under very hard acceleration you may archive + 1250 Nm.

BTW, the Getrag MG-282 DIFFERENTIAL should handle up to 3500 Nm (short-time dynamic peak load).
We can be glad that the Getrag is so strong!

Furthermore, I have made some progress on the engine side!

Lightened flywheel installed:


Test-run with modified oil pump and lightweight flywheel:


RAM HD clutch installed:



Next I´ll search for hidden rust spots inside the engine bay and fix them before I install the tranny.
I need to build custom transmission mounts (on basis of stiffer Dodge Ram engine mounts).
I also ordered a polyurethane engine mount, but my poly parts have been lost

------------------
Patrick, Analysis Engineer
´88 Fiero GT 5-sp. Getrag

[This message has been edited by Moar (edited 03-22-2016).]