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R200 LSD's and breakaway SHIMMING DONE!


JMortensen

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I cut it back to 5 shims, and that got me 100 lbs. 4 shims = 40 lbs. I think I'm gonna run it in several months when the rest of the project is done and see what it does.

 

I'm not too scared of 100 lbs breakaway, because a lot of the posis I sold for Randys were 150 and better supposedly (they didn't really rate them that way).

 

I have a feeling it will really affect my turn in, seeing as how I was running 20 something lbs before, but I've got adjustable everything so I should be able to tune out any push.

 

I can't believe this thing required .020 shim to get up to 100 lbs. The clutches were not really worn, so I can only imagine that they tuned them down in later years??? Having been in a car with a clutch style LSD with no additive I can see why they would want to do that.

 

Anyway with the rate that I get things done I'll let you all know how it works next June... :D

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  • 1 month later...

Got an interesting email from Gordon Glasgow, thought it would be nice to share with everyone here who was interested in this:

 

Hi, Jon. A friend of mine who is vintage-racing his 2000 brought over his

new Nismo limited-slip unit so we could test it. He'd run it a few times

already and was getting lots of wheelspin.

 

We tested it and it was only about 10 lb/ft of breakaway, so we pulled it

apart. Guess what: it had two spring plates on each side and no spring

disks, and each side had three clutch plates and only one clutch disk. So

all the work was being done by that one clutch disk on each side. BTW, it

was a 4-pinion unit.

 

I threw a .010" shim in it just for starters and that brought it up only to

about 20-25 lb/ft. So I threw in another .010" shim and it measured 90

lb/ft. I talked to him after the next race and he said it worked great.

 

I have no idea what Nismo is doing putting them together like that. It just

doesn't make sense. But it does sound similar to the setup you found, so I'm

thinking it maybe wasn't a PO issue after all. Interesting.

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  • 4 months later...
Guest Luigi

Been absent from here for awhile. I will check my 300zx factory manual tonight. If memory serves (big if) the factory says 14-27lbs. I made a strap with an 3/8" extension in it and checked mine, it was ~20 lbs. used a snap on torque-o-meter. I didn't have clutches so I put it together. Works OK. launches good. BUT NO TRACK TIME YET. so I guess I'm saying the trial and error method is it. Also, I mentioned this in a post a long time ago, these rear ends build heat so watch fluid type and level, consider a cooler and if you are in there open up the backlash a BIT.

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  • 2 years later...

So after seeing my Diff yesterday, what do you personally think I should do, shim wise, to my LSD for my day to day driving?

 

I want to be able to have the diff as a daily driver but want that aggressive kick in the butt (both tires ripping out from under me ) when I feel like showing off. Just remember that I'm just under 175 RWHP and would love to drift around the parking lot every once in a while.

 

I'm thinking 30 odd pounds of break-away but what will the present set up do? both tires slipping easily or will it only kick in when I get real aggressive with the throttle?

 

Just me throwing questions in the air.

 

Dave.

Zs-ondabrain from CZCC

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For a street car the stock setup is OK, and it is torque sensitive so I doubt you'd spin tires too often, but when I had mine like that it would occasionally spin one tire when I was going over a severely cambered turn. If you want to shim it up a bit we can get some shim stock from http://www.mcmaster.com. I think I used part #9011K85. We can go off of my previous shimming measurements and just throw in 4 shims at .004 thickness each and that should get roughly 45 lbs breakaway.

 

You can run it just the way it is and I'm sure it would be just fine, but since we're in there anyway and it only costs about $15 or $20 to do it, if it were my car I'd do it. You're going to LOVE the difference it makes.

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  • 2 years later...
  • 2 years later...
  • 3 months later...

Hello everyone.

 

I bought used R200 lsd unit and after opened it, discovered that other side was missing all disks and springs. Well as you might quess, these parts are pita to get, especially for a guy living near north pole...

 

Hope some day I found parts to put this together. Be wiser, never buy parts without pictures of all parts icluded.....

So incase some one needs to get friction plates made, I desided to share this cad drawing I made to everyone.

 

Download

 

post-27964-092651100 1332449935_thumb.jpg

 

 

 

 

Br

Silli

Finland

Edited by Silli
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  • 3 weeks later...
  • 1 month later...

Someone please advice.

I have now tested my rebuilt R200 with all new bearings and used pinion/ring-gears. It kept wining before rebuilt and now wining is still there. When I cruise around 60 mph or more wininig is loud, if I accelerate or declerate it goes silent. Gear contact pattern is quite spot on, backlash is 0.13mm and preload is around 2 nm. So everything is in specs......

 

Do I try bit more backlash or less. I dont want to pull pinion bearing out to readjust pinion hight as most cases it wont come out in one peace.

 

Thanks in advance

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Mine does the same. I have the solid front diff mount which I assumed was the cause.

 

What diff mount are you using?

Rear mount is original rubbered one, the whole member has polybushings allaround.
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  • 6 months later...

The first "clutch upgrade"  I did was on my 3.90 CLSD.  Used 6 new clutches from Savage42 to replace the 2 old ones, removed the two outer spacers, installed 4 shims.  Bench tested wet to 62#.  Chattered (banged) like crazy in car-went to three tubes of Trans-X and it only chatters occasionally.

 

Built-up a 3.54 this week using the carrier from a 3.70 CLSD into the case and ring gear of the 3.54 open.  Used 4 nissan clutches and 2 clutches form Savage42.  No shims to try to avoid ratcheting or chatter I have in the 3.90.  Just put it all together, back in case for wet test.  Its a spool.  Back to the drawing board.

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The Nissan clutches are thicker than Gary's clutches. Run 4 of his with the 2 stock Nissan clutches and that should get you in the ballpark. If you did it the other way, I think you'd have something like .020" thicker clutch stack. You can double check in the other FAQ thread about adding clutches.

 

I just PM'd this to RebekahsZ, but might be useful for others too:

 

 

There's two interrelated things going on:

1. Preload friction: This is the load on the clutch pack when you're off the gas. It has an effect on the total lockup also.

2. Clutch friction: By installing the extra clutches you're adding A LOT more surface area for friction to be generated. If you do that, then I don't think the extra shimming is really necessary. Without having tested it, I would think that you would have WAAAAAY more lockup with the extra clutches than you would with the stock unit shimmed to 100 lbs.

 

I think of it like a single disk clutch that a street car uses vs a triple disk NASCAR clutch for a transmission. You can run a super tight single pressure plate where you are basically doing a leg press with your left foot every time you switch gears, or run a triple plate with very light weight pressure plate springs, and the multiple surfaces will still hold down a ton more power than the single.

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That would make sense if the Nissan clutch discs are thicker. I don't have good enough quality calipers to measure an appreciable difference but that would make sense. In my other diff I used all 6 new clutches. I will try that again and report back. I want this diff to be a good bit looser than the other one. My target is 30-40 pounds. That is a SWAG- I just know I didn't like 62. I do so need to invest in some good calipers and dial indicators. Santa?

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Wrapping it up for the night (is it still night?).  Gonna summarize the past 3-ish day's work on this diff.  This is my second R200 CLSD build up.  First CLSD was last spring: a 3.90 out of a Z31.  Car is a drag/autocross/sunny-day commuter.  I read all over this site and decided to swap out the 2 clutches for 6 clutches from Savage42.  Cut 4 shims of .004 and slapped it all together=62# breakaway wet.  Put it in car and couldn't tolerate the banging on slow turns.  On advice, drained the diff, started over with 3 tubes of Trans-X and topped it off with Synthetic LSD 75W-140 oil.  Still banged-a lot.  Felt like I was living out a Ricky Martin song.  Did about an hour of circles both ways in a parking lot-that helped a lot, so now the diff only bangs about once in a commute.  Decided the 3.90 is perfect for 1/4-mile (one track in the state), but kind of in-between shifts for the 1/8-mile (4 tracks within an hour).  So, I got a 3.54 open from one member and a 3.70 Z31 CLSD from another member and put them together.  Put the 3.54 ring gear on the CLSD carrier and plugged it into the 3.54 case.  Now the fun starts.

 

In order to have lots of clutches, but no banging, for this diff I wanted to do something different from my 3.90 diff.  Here is a review of the options I tried.

1. 6 clutch mod + 2 shims = spool, which means that I got to 120# breakaway torque before quitting.

2. 6 clutch mod + no shims = spool

3. Stock configuration: 2 clutches and put back big spacer washers = 13# breakaway.

4,5,6.  Tried different combinations of Datsun clutches and Savage42 clutches=spool every time.

Threw in the towel for the clutch mod.

7. Stock configuration + 2 shims (phillips head screws only, ring gear not installed-this was the only trial that didn't include torqueing the ring gear to 60#) = 19#

8. Stock configuration + 2 shims (installed and torqued ring gear) = 24#

9. Stock configuration + 4 shims = 32# breakaway.

 

Thought about trying 5 shims, but I've had enough.  Wet bench testing was done with synthetic LSD 75W140 gear oil mixed with 1 tube of Trans-X.  Gonna run straight synthetic LSD 75W140 with no Trans-X until first oil change, which will be pretty quick if this one bangs too.  Cleaned up, cleaned the ring gear bolts and ring gear and put it together with blue locktite, 60# for each ring gear bolt and 70# for the bearing cap bolts.  It seems that this project, for me, defies a "cook-book."  The real miracle is that I didn't bust my azz walking around in all that oil.  None of my tools should rust.  Justification for all this:  all the cool kids are doin' it.

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