Neville Jones
|
| posted on 22/3/16 at 12:44 PM |
|
|
Just putting in a flexi mount at the diff front mount holes, as most do, won't solve the breakage problems alone.
The broken diffs I had were all mounted with compliant front mounts.
The problem wasn't resolved until the front mount was taken a good way up the tunnel to reduce the torsional loads on the diff nose and the
reactions in the 'wings'/arms.
Cheers,
Nev.
|
|
|
|
|
normspanners
|
| posted on 22/3/16 at 11:04 PM |
|
|
Thanks Nev , as said the mx5 diff doesnt lend its self to the extended nose idea in the sr2 because there is not a lot of space ( read NONE) to the
right of the pinion, because the pinion is itself to the right of the crown wheel, in fact the drive flange has touched the ladder on the right, as
per my photos, when the oxbow snapped.
The rx8 diff on the other hand has its front ppf mount is on the left and that is where there is some space, on this car.
At the moment it is looking like the RX8 unit JUST fits in with mm's to spare.
[Edited on 24/3/16 by normspanners]
[Edited on 24/3/16 by normspanners]
|
|
|
Rocket_Rabbit
|
| posted on 1/6/16 at 02:11 PM |
|
|
A bit of an update:
The rear end has now been fixed. See the picture below and I'll explain what each number is:
1) This is a diff from an RX8 as opposed to the MX5 item that was broken.
2) A custom made oxbow mount to replace the RX8 original. It bolts into custom clevis mounts that then bolt into the original SR2 mounts.
Incidentally, the OEM mounts had bent quite a bit upon the diff breaking. They had to be pulled up back into place.
3) A tie bar has been installed to transfer the torque reaction of the propshaft upto the roll cage.
4) An additional lug mount has been attached to allow a more compliant damper movement and to attach the tie bar from the diff mount.
5) Hard to see, but in order to install the diff, the rear bar had to be cut out. This has been 'flanged' and bolted in.
6) The damper has been re positioned in order to achieve better leverage and more travel. It is now running a 400lbs spring.
7) Again, hard to see but this is where the new diff nose mount now attaches. Made from part of the RX8 PowerPlant Frame it provide resistance to the
torque reaction from the driveshafts.
8) The CV cups are a hybrid construction from the RX8 flange and the MX5 cup. A number of shafts were tried, but didn't quite fit. This
solution allows the spider and shaft from an MX5 to slot straight in should it break and mate up to the hub
There is still more work to do on the car as the front is suffering from similar issues to the rear. The front upper wishbones bend under braking and
foul the dampers. This should be a simple fix by bracing the upper spherical bearing joints with a bar.
The lugs for the rear mounts on the lower front wishbones are welded on in completely different locations and orientations!
The steering rack is not in line.
The front ball joints are seemingly of different tapers as they don't locate symmetrically. I have ordered new ones but on a car that has been
built by Roadrunner and done, apparently, 50 miles, you'd have hoped this would have been fixed.
|
|
|
