HR31 LSD into a Zed

[HKSZ]

I've got a long nose r200 4.4 lsd, about to fit in my 240z but the yoke has a bigger bolt spacing what do I?

 

[dat2kman]

Thats one, of the two slight issues, with hr31 lsd units.

You jeed to swap it over for a r200 yoke that would come off a later 260 or 280 with a r200.

Or get a hr31 tailshaft and get a driveshaft shop to put that flange onto your existing tailshaft.

 

The second issue is regards the lesser number of clutch discs, and the spacers installed.

Fortunately the clutch discs from Rodeo rear diffs ( some) fit perfectly, and are slightly thicker 2.1 mm vs 1.9 mm.

[luvemfast]

I've got a long nose r200 4.4 lsd, about to fit in my 240z but the yoke has a bigger bolt spacing what do I?

If you have access to a mill.

Take off the flange and redrill it, in the correct positions. 

[zzzzed]

I had this problem just 2 weeks ago when fitting my LSD. I just undid the bolt on the end of the yoke and slipped it off and swapped it with my old non LSD r200

[HKSZ]

Thanks for all the reply guys, just took another look I'd have to swap yokes as this one is rectangle so no meat to redrill.

I haven't changed yokes between two diffs before, I'll need a diff mechanic to change it

 

The second issue is regards the lesser number of clutch discs, and the spacers installed.

Fortunately the clutch discs from Rodeo rear diffs ( some) fit perfectly, and are slightly thicker 2.1 mm vs 1.9 mm.

Jason I'm not even sure if its clutch or viscous, any easy way to tell?

[luvemfast]

I'll need a diff mechanic to change it

You're kidding right?

Isn't it just one nut up the center line?

[NZeder]

Right lets clear this up a bit.

 

Your old diff had the picture in the center?

Your new HR31 LSD has the flange show on the right?

 

So as pointed out you have 2 options (maybe 3 if the redrill option is taken).

 

Option 1 - no drive shaft mods = using an impact gun and the correct size impact socket - undo the large nut in the center of the flange on both the old and diff and the LSD - swap them over and refit the nut torque to the correct setting - which is 149ft/lb for the drive pinion nut (from Haynes 280zx manual)

 

Option 2 - get the HR31 drive shaft and cut the end off the drive shaft that mounts to the diff - take this and your drive shaft to a driveline shop and have them put the HR31 end on the rear of your drive shaft.

 

Option 3 - as the larger round flange has the same 2" center spigot and enough meet around it you can redrill for the old flange PCD.

 

This assumes you have the center flange shown and the right flange shown. If however you have the smaller round flange standard then you only have Option 1.

 

here is the image

[dat2kman]

All long noses should be clutch pack lsd's, if they have one fitted.

 

The HR31's, to save money, only have half complement of clutch plates, and two thick spacer rings. Perfectly fine for street and sprited driving.

Turns to mush in race conditions.

 

Need to fabricate a bit of long rhs bar, with a correct sized shanked bolt in end.

Bolt has to be close to one side.

Bit of rhs about 5' long.say 45x 20 or 50x25 is fine.

 

Attach by a bolt, a bit of flat stock say 25 or 30mm x5 or 6 mm, about 600 long, drill hole each end, bolt the flat to the rhs, so that at one end, you have 2x8 mm diam bolts poking out that are then able to be placed into your diff yoke.

 

You'll now see why they need to be on the edges, so that you can get a socket inbetween the rhs and the flat, 3/4" drive is good, and a long bar.

 

You do need to jack car up high, put it on ramps, or stands, fiddle about so that the rhs is braced to floor, socket on pinnion shaft, long long bar on socket, use your leg for max muscle, and she'll undo.

Reverse for doing up.

 

I use this method for all types of pinion flange, hence the adjustability.

[Zedman240®]

I did the exact same thing quite a few years ago when I removed the LSD R200 from a fire damaged R31 turbo coupe; removed the flange from my old R200 with impact socket on air gun, and as Mike has said, tighten to correct torque... then removed stub axles from my old R200, swap left to right and install into LSD diff. You should feel both axles "click" and lock in place when installed. If you look inside where the stub axles go in, you can see one is longer than the other. Its not that complicated to do.

 

Clutch pack LSD's should have resistance when trying to rotate one wheel in an opposite direction to the other when the rear is jacked up off the ground.

[HKSZ]

Thanks every one i'm going to get on and put this diff in the car

You're kidding right?

Isn't it just one nut up the center line?

Yeah, no I've done plenty of pinion seal replacements, don't have to worry about torque just punch mark shaft and nut then count turns out, it's adding a foreign part even to factory torque may not be the same load I had before

 

This assumes you have the center flange shown and the right flange shown. If however you have the smaller round flange standard then you only have Option 1.

I think I have to swap with a 280zx flange for now, otherwise i'd have to redrill and mill out centre

 

The second issue is regards the lesser number of clutch discs, and the spacers installed.

Fortunately the clutch discs from Rodeo rear diffs ( some) fit perfectly, and are slightly thicker 2.1 mm vs 1.9 mm.

I'll have to look into getting one of your conversions cause it dosen't sound like this diff is going to be as good as the Stan holmes one I'm pulling out

 

Steve

[zedevan]

I had different clutch plates put into my LSD to up the break away torque, and had to swap the flanges over for it to match up with the drive shaft.

 

Unfortunately i didn't realize the difference in flanges till I was trying to put the drive shaft bolts back in at the end of the swap over, but at least I'm more efficient at it now. Next on the list in the diff area is to put in the 'ron tyler' brace, I'm still not 100% sure on how to get the alignment correct without having to put the diff in and out a couple of times.

[NZeder]

If you don't have the RT diff mount yet this is a good source for one

 

http://www.technoversions.com/DiffMountHome.html

[zedevan]

Cheers, I already have one but after seeing that one I'm a bit concerned it doesn't have the clearance bends at the side for fuel lines etc, I'm hoping instead its just a bit shorter.

 

I'm planning to run it with the GM mount, and the lower mount (hence i'm not sure how to guarantee i'll install the mount in exactly the right sport). The TechnoVersions site recommends removing the original mount - is that how most people are running it?

[NZeder]

A friend ran his with both the GM and stock mount. First you have shape the GM mount so it follows the curve of the top of the diff. Then the top of the GM mount needs to be cut down a lot too, you end up cutting the top mount plate in the mount almost half its thickness. We no long do this as it is a pain to fit up with GM bolted to the RT bracket.

 

We now use a bump stop trimmed to a length so it starts to compress as the bottom cross member is bolted up.

 

Cheers

Mike

[HKSZ]

Opened up the back, definately a 4.4 and all the teeth in good nick. Can anyone confirm it looks like a clutch LSD or Viscous?

Steve

[dat2kman]

Clutch pack

Well bought

What are you planning to do with the car?

I ask the question, as, it will have the two thick spacer plates fitted, and if you were to use car for "spirited driving" or some track days,,, while it is out, and partially dismantled, you may wish to replace the spacers with additional clutch plates, and get the pre-lad tightened, from a stock of about 50 lbs to around 100 pounds breakaway.

 

Or, just stick it in and go!

[HKSZ]

Thanks again Jason, I picked it up a couple of years back for $600 on ebay so started thinking maybe it was viscous.

 

I'm putting it into my rally car, currently run a R180 4.8 Nismo which is the cats pyjamas on dirt but would like to try 4.4 cut down some wheel spin and more top end speed.

Got a local autocross in a couple of weeks so that will give some comparison, but yeah 50lbs dosen't sound impressive

Steve