Hi All,

Main questions:
Can anyone tell me the actual measurement of the crownwheel PCD from a 4.44:1 R200 from a R31, please? I'm not overly interested in "it's the same as X or Y car", I want the actual measurment.

How many bolts hold the crown-wheel to the diff hemisphere?

Secondard questions:
Does anyone know the diameter of the pinion shaft, at the bearings?
How far apart are the bearings, in a long-nose R200?
Does anyone know the spline count and diameter for the tail-shaft flange on the pinion shaft?
Anyone got good, detailed pics of a long nose R200 in pieces?

TIA!

Guest, direct quote off this ozdat from a while ago,


So if this answers any questions?
I know the H190 axles DO fit into the R200 SHORT NOSE LSD centre, as i tried last week. I am currently attempting to use the R200 short nose in the H190 housing.
What project have you got going?
Adam.

what are you trying to do?
i have a spare really noisey R200 that i can pull apart and get what ever you need exactley. PCD? realley difficult on a conical gearm and i have 3.7:1.
i can pull it apart monday - tuesday night if you give me what you want to know . i was planning on pullig it down anyway are you trying to fit an lsd centre to an open diff.

The info posted is a good start. Thanks! (and I searched, using R200 and dimensions as search terms but missed the post you quoted... ).

What I'm trying to do, is follow a vague lead I was given from a bloke at SSS Automotive a while ago... Apparently some R200 parts can be adapted into Mazda RX-7 Turbo diffs (Series 4 and 5), to get a decent ratio into the back of the RX-7.

I'd pretty well given up on the idea, and worked out a short nose "Franken-diff" solution using Mazda van, 929 and RX-7 parts, but I am now presented with a long-nose, 4.44 R200 for a decent price, so I figured it was worth investigating.

The S4 RX-7 diff has a 200mm crown-wheel, and is also a long-nose type of diff. I AM prepared to put some time and money into this idea if I can be reasonably sure I can get it to work, but...

The all-Mazda short-nose solution also has some teething problems with mounting the diff to the cross-member without breaking the mounts on the pinion carrier (both the rear of the diff and the cross-member are rubber mounted to the body, so can move relative to each other).

Sorry, forgot to add:

I'n a perfect world, I'd like to know all of the following (although I recognise it would be an imposition!):

Pitch circle diameter of the crown wheel mounting bolts.
Number of CW mounting bolts.
Size of CW mounting bolts.
Total length of pinion gear and shaft.
Height of each pinion bearing.
Diameter of pinion shaft under each bearing.
Distance between pinion bearings.
Diameter and number of splines on the end of the pinion shaft.

Diameter and number of splines of stub-shafts.
PCD of tail-shaft flange mounting bolts.
Width of hemisphere (bearing to bearing).

I'll measure up my disassembled RX-7 diff tonight, and see if it is worth pursuing... If it is, it'll probably be easier for me to go and buy a dead/crook R200 and go from there. Assuming I can find one, of course...

Does anyone know if the CW mounting flange on the hemisphere is moved according to the ratio originally fitted to it (Mazda and Toyota both did this)?

Cheers!

i have a dead / crook R200 if you are keen. it is howling due to the wrong torque on the pinion flange nut has done not much work 200k since then it is long nose 3.7

whoever told you that R200 and infini diffs are interchangeable obviously has never done a side-by-side comparison.

about the only parts i can think of being interchangeable are the bearings.

that said, RX7 IRS diffs are pretty strong in their own right, but a bit more like an R180 than an R200.

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The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

The comment was not that they were interchangable, it was that "some R200 parts can be adapted into Mazda housing"... I'm not expecting a direct bolt-in - this is why I'm asking the questions I've been asking!

If the bearings are interchangable, then that's a BIG start!!!

There's no problem with the strength of the Mazda diff, just that I'm stuck with lousy ratios. 4.1 or 3.9 are standard, 4.3 is available at considerable expense, but I want (something like) 4.44 or 4.56.