R200 Diff Centre - 10Mm Or 12Mm

[Tony de Wonderful]

Does anyone now the definitive answers on this?

It's bolt hole sizes for bolting the ring gear to the center.

I got a Cusco 1-way and it had 10 mm holes but was told it would fit an R33.

I'm led to believe only very early R200 diffs like on the Z31 had 10 mm holes, but did the NA Skylines have 10 mm too?

[Tony de Wonderful]

Ok this is what happened.

I got a used R200 Cusco mech diff which was supposed to fit R32/R33/R34.

My mechanic said it looks about right.

He took my OEM R33 GTST VLSD out, unbolted the crown/ring gear and when he tried to bolt the crown/ring gear to the Cusco center, the bolt holes on the Cusco center were slightly too small too accommodate the OEM bolts.

He reckons the OEM bolts are 1/2" unified which is 12.7 mm. I had thought they were 12 mm metric. He reckons the Cusco centre had bolt holes which were 12 mm metric but he is not 100% sure, he just drilled them out to take the OEM bolts. I guess they could have been 12mm or 11mm?

So do I have grounds to tell the person who sold me the Cusco LSD that it was not exactly what it was advertised as and took 2 hours extra work to fit?

The mech who did my work is highly respected and not new to Skylines by far.

[BOZ22N]

I am sure that the r33-34 hemispheres are 12 mm not sure about the r32.

The S series hemisphere I think were 11 mm, I do have this written down some where I will have to go looking for it.

But if you had to modify the hemisphere or crown wheel you were sold the wrong part for your model. I have fitted a few R series and S series diggs and never had to modify them.

[Tony de Wonderful]

I am sure that the r33-34 hemispheres are 12 mm not sure about the r32.

The S series hemisphere I think were 11 mm, I do have this written down some where I will have to go looking for it.

But if you had to modify the hemisphere or crown wheel you were sold the wrong part for your model. I have fitted a few R series and S series diggs and never had to modify them.

Well my mechanic said the OEM ring gear which was mounted to the OEM VLSD was 1/2" uni (12.7mm) bolt holes. This had been on the car since it was made.

Basically yes had to open up the bolt holes in the cusco center. I've never heard of Nissan stuff being 12.7 mm. I've heard of 10mm, 11mm, 12mm and even 13mm bolt hole sizes on diff ring gears with Nissan diffs. I dunno if people just say 12mm when they mean 1/2" uni? Do they? I know some Jap stuff is funny as they mix and match metric and imperial.

It is definitely an R200 diff as the old ring gear fits perfect over the center.

It would make more sense to me if the Cusco was 11 or 10 mm and had to be opened to 12 mm but this 1/2" uni (12.7mm) size which I am told my ring gear is has me confused.

[GTSBoy]

There is no way that the diff bolts in a Nissan made in the 1990s are 1/2" UNF (not unified, UNF). Metric or nothing else at all. It's not a Commodore.

[Tony de Wonderful]

There is no way that the diff bolts in a Nissan made in the 1990s are 1/2" UNF (not unified, UNF). Metric or nothing else at all. It's not a Commodore.

It's probably more likely that the Cusco had 10mm or 11mm bolt holes do you think then? I know very early R200's are 10mm and I think some R32 R200 were 11mm??

This guy knows what he is talking about though. He was mechanic for a R32 GTR race team back in the day.

[GTSBoy]

Well, I should have said that there's no way the ORIGINAL bolts in an R32 diff were 1/2".....I suppose it is possible that some deranged maniac drill&tapped everything out to put 1/2" stuff in there at some time in the past. But it would be a wierd situation or person that would cause that to happen.

There have been a couple of bolt sizes in Nissan diffs, so your theory about the Cusco centre being the wrong one is quite possible.

[Tony de Wonderful]

Well, I should have said that there's no way the ORIGINAL bolts in an R32 diff were 1/2".....I suppose it is possible that some deranged maniac drill&tapped everything out to put 1/2" stuff in there at some time in the past. But it would be a wierd situation or person that would cause that to happen.

There have been a couple of bolt sizes in Nissan diffs, so your theory about the Cusco centre being the wrong one is quite possible.

I'm reasonably sure the diff has never been opened. The car was stock when I acquired it.

I just realised I have the VLSD center so will measure it.

EDIT - Ok I just measured the bolt holes in the VLSD which came out of the car and I make them as 13mm but that is w/out a proper vernier thingy just a ruler and a 'wedge' nozzle gauge. This is just plain odd. It is dark here, will try and get a part number off the VLSD tomorrow.

Edited November 30, 2011 by Tony de Wonderful

[Tony de Wonderful]

Well I had a better look at the VLSD center that came out of the car. The only codes I could see stamped on it are 'C5 D6'. I can't find anything on google about this code for R200 diffs. Strangely, Ford seems to uses these codes for LSD's???

Anyway the bolt holes are about 13mm, definitely very slightly larger than 1/2" which would make sense if you were going to put 1/2" UNF bolt through them?

[badhairdave]

Cusco note 2 different model diff's as compatible with r33's (one of which is compatible with s14/15), and different numbers again for r32, and r34 but that said it's really luck of the draw sometimes, particularly if you have a car from early or late in the production run.

Nismo diff centres all have the larger holes and are supplied with crown wheel bolts that have 13mm ish shanks and 12mm threads. Basically so if you have a crown wheel/centre with the smaller bolts you can still use your crown wheel and the new bolts, if you have one with the bigger thread you re use your old bolts.

I'm sure i still have that bag of bolts in a drawer somewhere as i didn't need them for my old r32's diff....