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Phyxius

I got a '87 z31 LSD (w/ some questions)

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I found it at a local jy that I frequent. A new arrival was a maroon turbo z31. I walked over to check it out...looked under the rear and my heart hit the floor...there...was a finned cover. I hastily checked the door plate to make sure that it was the right model year to have a lsd and it was! I asked the owner how much and they he says... "$100 brake to brake...just leave the wheels" I had to take it out, but I still feel like I stole it from him. :lol:

 

So, I now have it sitting in my kitchen along with the cv axles, both control arms complete with brakes. I would have taken the rear subframe too, but it wouldnt fit in my car. :)

 

Now for the questions:

 

1.) While it was still in the car (and the car was lifted), I turned one wheel and the other turned the opposite direction (with the car in neutral). That struck me as odd so I turned the driveshaft and both turned the same direction. I took the cover off just to be certain that it was an LSD.

So the question is, does it need rebuilding or shimming or what? There was no metal or any other foriegn matter in the oil.

 

2.) I've read about the possibility of using the z31 cvs and stub axles in the 280zx control arms using the z31 bearings. The details are still a bit fuzzy to me about if the z31 cvs are too long or will fit if the stub axles are swapped out. Can anyone clear this up?

 

3.) I've asked this question in another thread, but I figured I'd ask it here again... Will my driveshaft that is currently mated to my R180 bolt up to the pinion flange on the z31 r200?

 

Thanks in advance...

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1.) While it was still in the car (and the car was lifted)' date=' I turned one wheel and the other turned the opposite direction (with the car in neutral). That struck me as odd so I turned the driveshaft and both turned the same direction. I took the cover off just to be certain that it was an LSD.

So the question is, does it need rebuilding or shimming or what? There was no metal or any other foriegn matter in the oil.[/quote']

That is a weird one. The wheels should spin in the same direction, even with very little breakaway. Did you take a pic of what the carrier looked like? Might not be LSD, I seem to remember that the early 87 wasn't, or maybe yours got swapped out at some point??? If you need to shim it, here's my thread on shimming my diff: http://forums.hybridz.org/showthread.php?t=92629

 

2.) I've read about the possibility of using the z31 cvs and stub axles in the 280zx control arms using the z31 bearings. The details are still a bit fuzzy to me about if the z31 cvs are too long or will fit if the stub axles are swapped out. Can anyone clear this up?

Sure. That is not a possibility. Or at least not a bolt in. The S130 uses semi-trailing arm suspension. Your Z uses lower control arms. Totally different. The Z31 I think also has semi-trailing arms. So none of that stuff bolts onto your Z. You'd have to REALLY modify everything, and then you'd end up with a questionable end result of having semi-trailing arm suspension with all of it's squat and toe change.

 

The easiest thing to do is use the Z31 CVs with Modern Motorsports CV adapters. You can get the billet adapter, or just send them your old companion flange and they'll weld on an adapter and ship it back to you.

 

EDIT--Scratch that. You have a 280ZX. I should read more closely before I open my mouth. I don't know the answer to this question...

 

3.) I've asked this question in another thread, but I figured I'd ask it here again... Will my driveshaft that is currently mated to my R180 bolt up to the pinion flange on the z31 r200?

No, but it will bolt onto a 280Z R200 pinion flange. Basically you need to pull the pinion nut, then pull the flange off, put the new pinion flange on, and put the nut back on. You can get a new nut from Nissan, and you can make a good argument for doing that, but I'd just red loctite it and put it on TIGHT. I seem to remember the correct torque spec being ~150 ft/lbs.

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That is a weird one. The wheels should spin in the same direction, even with very little breakaway. Did you take a pic of what the carrier looked like? Might not be LSD, I seem to remember that the early 87 wasn't, or maybe yours got swapped out at some point??? If you need to shim it, here's my thread on shimming my diff: [url']http://forums.hybridz.org/showthread.php?t=92629[/url]

 

I'm sure it is an LSD. I don't have pictures, but it's got a full cage with only a few holes and i can see the pinion with the cam on the end between the pressure rings.

 

on the simming thing... I got some shim stock in .004 like you said, but I'm not really sure what shape to make the shims. I'm thinking a donut shape would do it but may be hard to reproduce exactly for each shim.

 

No, but it will bolt onto a 280Z R200 pinion flange. Basically you need to pull the pinion nut, then pull the flange off, put the new pinion flange on, and put the nut back on.

 

That is what I was afraid of. There aren't many salvage yards around this area and very few have Z's of any sort. The chances of finding anything that's not a z31 are slim.

 

Does anyone have a 280z pinion flange they'd sell me?

 

Also, I forgot to ask this before... Will r200 half shafts work with this diff? And will r200 half shafts bolt to the stub axles where the r180 half shafts did?

(i'm still trying to decide how to get the power to the wheels)

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on the simming thing... I got some shim stock in .004 like you said, but I'm not really sure what shape to make the shims. I'm thinking a donut shape would do it but may be hard to reproduce exactly for each shim.

I traced the friction plate (with the tabs on the outside) and cut the shape out with a pair of meat scissors. I installed them on the outside of the clutch pack. So it is shim, thick washer spacer thing, then clutches. You could clearly see on mine that the thick spacer thing had never moved as it was stained by the oil. That means that you could probably just cut the shims to the donut shape of the spacer and it would probably be fine. I just did mine so that the tabs would keep them centered while I put it all back together.

 

Also' date=' I forgot to ask this before... Will r200 half shafts work with this diff? And will r200 half shafts bolt to the stub axles where the r180 half shafts did?

(i'm still trying to decide how to get the power to the wheels)[/quote']

There is no difference between an R160, R180, or R200 halfshaft. What may be a problem is the halfshaft bottoming out, as John Coffey points out on his website here: http://www.betamotorsports.com/benchracing/index.html Click on R200 Handling Issues.

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I traced the friction plate (with the tabs on the outside) and cut the shape out with a pair of meat scissors. I installed them on the outside of the clutch pack. So it is shim, thick washer spacer thing, then clutches. You could clearly see on mine that the thick spacer thing had never moved as it was stained by the oil. That means that you could probably just cut the shims to the donut shape of the spacer and it would probably be fine. I just did mine so that the tabs would keep them centered while I put it all back together.

 

I think I'll do it with the tabs as well. Thanks for the info.

 

 

There is no difference between an R160, R180, or R200 halfshaft. What may be a problem is the halfshaft bottoming out, as John Coffey points out on his website here: http://www.betamotorsports.com/benchracing/index.html[/url'] Click on R200 Handling Issues.

 

My halfshaft is the sort without the seperate flange that goes into the differential. The U-joint attaches the splined section to the main section. Are all R200 halfshafts the type with the seperate flange? Are the flanges bolt in or circlip in?

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Oh, forgot that that type of halfshaft existed. I don't think there is a length difference, but you can check against the measurements on John's site. I believe all the R200's are the type with the separate flange. I believe you can run your axles no problem, but testing the breakaway is going to be a little more tricky. I guess you'll have to test at the stub axles, not sure if running the test through the U-joints is going to change the torque values much. Plus you'll have to reinstall the diff every time you want to test it. Might be worth it to see if you can find those side stubs too, if only for testing.

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I'm saying that the HALFSHAFTS are the same between the R160, R180, and R200. Again, I forgot that your halfshaft with the stub built into it even existed. I don't know if the R180 and R200 stub shafts are the same spline or not. I'd guess not, but then I do know that they are the same on the R180 and R190. The main difference I can see is that the R200 stub shafts are retained by a circlip. I think the early R180 bolt in, and the later ones have a circlip, but I'm not an expert on the 180 so definitely double check me on that one. Whether or not they'll plug in, that one I can't help you with. Maybe someone like zcarnut could help you out with that question.

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Well... I found out why it was acting like an open diff....

 

lsdclutches.JPG

 

As you can see, the tabs that hold these friction discs have been stripped away. Must have been something pretty violent to cause this. Maybe several 6k rpm clutch dumps or something?

 

Everything else looked okay. There was fresh gear oil in the diff when I got it, so someone must have done that in a last ditch effort to remedy the diff not working right... who knows...

 

I guess the question now is where can I order 2 new friction discs from?

 

*EDIT* I also noticed that I have 4 spring plates and no spring discs. You can see that my friction disks have a spiral groove. The friction plates all have axial grooves ( like the spokes on a wheel). it also doesnt seem that I have as many clutches as some others have reported...i'm about to take look again.

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Here you can see the model numbers...

model.JPG

 

 

Here are all the parts of the internals. Note only 2 spring plates per side. No spring disks. Also note 2 friction plates per side and only 1 friction disk per sideinternals.jpg

 

 

Here are the 3 clutches for one side. Note the spiral grooves and axial grooves. The friction plate on the left shows some wear. Probably due to the tabs from the friction disk when they broke off. It is not severe, and I think it is still servicable.

 

clutches.jpg

 

Here is some sort of buildup on the side gear. It prevents it from coming out of the pressure disk. The other one has a similar buildup. Perhaps this is remnant of the tabs that broke off?

sidegearmark.jpg

 

 

Here is some wear made by the pinion gears on the inside of the pressure disk. It is very smooth... with no edges. I figure it is supposed to be there since there is nothing to keep the pinion gears from rubbing there.

pressureplatewear.jpg

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Looks just like mine. Does it have a thick spacer piece? I can't see that in your pics where you have all the clutches laid out.

 

Sounds like replace the broken clutches and shim to an appropriate level, then you're done. As long as the gears aren't galled it should be fine. Might want to check the ring and pinion for damage too. If the gears and bearings look good then you should be good to go.

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For reference:

 

Washer - 3.20mm

spring plate - 1.70

spring plate - 1.68

friction plate - 1.68

friction disk - 1.70

friction plate - 1.70

center chunk - 69.67

friction plate - 1.80

friction disk - 1.75

friction plate - 1.70

spring plate - 1.70

spring plate - 1.70

Washer - 3.20

 

Total - center chunk = 23.51 if I added correctly.

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Looks just like mine. Does it have a thick spacer piece? I can't see that in your pics where you have all the clutches laid out.

 

Sounds like replace the broken clutches and shim to an appropriate level' date=' then you're done. As long as the gears aren't galled it should be fine. Might want to check the ring and pinion for damage too. If the gears and bearings look good then you should be good to go.[/quote']

 

If by spacer, you are talking about the big washers, then yes, Mine has them. (see above for measurements)

 

All of the gears look perfect. Almost like they haven't been used at all. The bearings also look to be in good condition except for a very tiny amount of scoring on the "hat" of the cage under the bearing.

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Great! It's still a hell of a nice find then. All you need to do is get the two clutches and reassemble, maybe shim to your liking if you want.

 

Is it true that it takes over 6 weeks to get clutches from nissan??? That's insane for such small pieces. Are there any other sources?

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I don't think there are any other US suppliers, at least I haven't found any. I know the diffs are manufactured by Fuji Heavy Industries, same company that owns Subaru. I also know that http://www.reiderracing.com and http://www.differentials.com sell this same LSD under the name Power Brute. You might try calling one of them and asking if you can get the clutches from them, or try track down someone in Japan who can get them direct from the manufacturer if that is possible. Even if it didn't save you time to buy direct it might save $$$.

 

Good luck! Even at a 6 week wait, you should still be pretty stoked.

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Thanks for the lead on the clutches. That's a pretty good deal comparatively, although you can buy a whole set of Eaton carbon fiber clutches for a domestic and they're only like $40. Even so, at $15 a pop you might consider trying to eliminate the washers. If that diff had more clutch disks in it it probably wouldn't have sheared the teeth off.

 

I'm almost sorry I saw that. Makes me want to take mine back apart and add more clutches...

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Thanks for the lead on the clutches. That's a pretty good deal comparatively' date=' although you can buy a whole set of Eaton carbon fiber clutches for a domestic and they're only like $40. Even so, at $15 a pop you might consider trying to eliminate the washers. If that diff had more clutch disks in it it probably wouldn't have sheared the teeth off.

 

I'm almost sorry I saw that. Makes me want to take mine back apart and add more clutches...[/quote']

 

I was thinking the exact same thing. I wonder what the performance difference is between grooved and smooth...

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