240Z: Subaru R180 LSD Diff swap Parts

So, with the recent progress on the chassis and body, i thought it’s time to kickstart some long-pending projects. One thing i had in mind for a while was to fix the differntial. It was not really broken but i never liked the red colour which the previous owner applied to it everywhere. also the upper plug was completely stuck, there were some strange rubber bumper-things added in some places, the breather vent was closed with some kind of wax or whatever this was and the mean seal was leaking.

It’s an original European 3.9 R180 Open Differential as standard on all 5-speed Manual Z’s (= all european spec cars). I thought when putting in the work anyway, why not upgrade to a limited slip? First of all i disassembled the old one to confirm it’s a 39:10, to see what shape the internals were in. I thought i’d give it a test to remove paint with paint stripper from the diff cover. that worked out, but somehow the metal below looked strange. like the outer layer had chipped off, or someone had added a silver layer of powedercoat. I thought i better not use it on the car.

At the end, i found a good Subaru Clutch type R180 “K” LSD differential for a reasonable price. so i thought i just go for the whole swap.
It’s from a WRX STI, and also an 3.9, because it’s considered the best “all round” ratio for a street driven Euro-spec 5-speed transmission setup.
The only thing you need to do is to install some drive shaft adapters, and swap the propeller shaft flange. Of cour’se it’s recommended to replace all the seals and stuff while at it anyway.
Left Subaru LSD, right side Original Datsun (Hitachi) Open differential:

You can see the big “K” on the Subaru differential which usually differentiates the Subaru diffs from the datsun ones.

I also collected various parts. And had bought a cheap kit in the past, so i have all the parts to get them both back together. The subaru one will get the full treatment with all the OEM parts and Keamari drive shaft adapters.
The Original Datsun one will get the cheap parts treatment, just to make sure it doesn’t leak while in storage.

Here’s a closer look at the subie diff, Kameari shaft adapters and the NOS parts:

And here the original / Repladed parts and additionally some cheap seals.

I hope i find some time to get it done soon. I also plan to repaint the Subaru diff, while at it anyway, but need to see how to do this best, first.
And i have some more exciting news soon.