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JMortensen

R200 LSD's and breakaway SHIMMING DONE!

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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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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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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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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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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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The problem with the stock config is that you've only got the two clutches, one per side, driving the wheels. The ones with the outer tabs ride with the case. The reason that the clutches were made in the first place is because these diffs had a reputation for stripping the clutches at about 300whp. With your usage I think you're going to need the extra clutches to make it last. I'd suggest you take it apart and put the extra clutches back in. You can see some pics of stripped clutches here: http://forums.hybridz.org/topic/46653-cncd-lsd-clutches/page-2

 

I went and looked it up, and the stock clutch is .070" thick, and the replacements that were made in the original group buy were .063". So if people were getting about 45 lbs breakaway with 4 aftermarket clutches, that means they had .014" less total thickness than you have with the 4 stockers and 2 aftermarket clutches config that you PM'd me about. I'd just get a couple more from Gary if you need them and swap them in.

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I guess if I strip 'em, I strip 'em. I tried using all six new clutch discs and stacked it all up as described and it was a spool. I can't imagine what I did that was wrong. If each big spacer is the same thickness of two clutches, it should work, but for some reason it didn't. It was fine on my other diff. Maybe I was drinking beer on the first one do I was better lubricated.

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Ok, Jon, I'm gonna spend some more money and time on this. I got spme good sleep last night, so im re-motivated. Can you send a photo to my email [email protected] of the best style gauge for measuring the clutches and plates and ill go buy one and take some measurements. Maybe ill have some thousandths milled off the inside of the carrier lid then shim back up. Let me get one thing straight on the clutch stack up: a driven clutch goes directly against the center section, then friction plate-clutch-plate-clutch-friction plate-spring plate-spring plate-shims(if needed) then the lid. Mirror stack up on the other side. I don't like the idea of having a driven clutch right up against the center section, but if that is correct, I'm game. That is how I've been stacking them up. That is the way I'm reading the instructions in the early posts. Maybe there is something I'm just stacking wrong?

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The stack sounds right. As to a measuring device for the clutches, I'd suggest a micrometer. It doesn't have to be super accurate, Harbor Freight would be fine on that one. http://www.harborfreight.com/0-to-1-inch-range-digital-micrometer-895.html

 

You could mill the case, but really, I have to wonder if something else is going on. If everyone else (including you on your other diff) gets basically the same result, and on this one you get something totally different, it makes me think there is some other problem. I don't know what that problem might be off the top of my head, but seems like something is wrong there.

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I would just shim it to what is the "best" recommended stack for your powerlevel and then install it and drive it around a bit. I had the same problem assembling my obx and I just said eff it and installed it. A drive later and I could move the tires with my hand. Weird but true.

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There is a harbor freight nearby where I'm visiting for the holidays so the plan is to get one tomorrow. Kaito I was tempted to do that, but it has kind of sucked driving with an intermittent spool with the diff currently in my car. I just got an email from duragg (this forum and its members are great). His clutch stack is quite a bit different. It looks from his pictures that he put a clutch between his spring plates. Is it ok to put a clutch between or even directly against the two spring plates? Also, is there no problem having the inside driven clutch riding directly on the center section (dissimilar metals)? Duragg appears to have three driven clutches, and only three plates with tabs on the outside (can't tell if they atre spring plates or friction plates). I have 3 clutches, 2 grooved plates with tabs on the outside and 2 springs plates with tabs on the outside.

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Cross checked this thread and the clutch thread along with some photos from duragg. Comparing pictures, it looks like duragg has a power brute just like bjhines. The spring plates in the power brute look to be wavey looking at the wear pattern in the pictures. Apples and oranges again.

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Tore Z31 diff carrier down again.  Started by measuring all the discs and plates with my new Harbor Freight micrometer.

 

Savage42 clutch discs:  4 were 0.0623", 2 were 0.0633".

Stock clutch discs:  varied between 0.0685 and 0.0691" (I have 4 stock discs, 2 from this diff and 2 from my other one).

Stock clutch plates: varied between 0.0666 and 0.0695" (there are 4 clutch plates in the stock diff)

Stock spring plates: varied from 0.0688 and 0.0690" (there are 4 spring plates in the stock diff)

Stock spacer: 0.1275 and 0.1280" (there are two).

 

I inspected the clutch discs from Savage42.  Three of the 4 had some burs that looked like weld splatter on the "gear teeth."  I had previously judged these to be in a position that made the burs inconsequential.  That is true, unless the burred discs is placed directly on the "center section."  I cleanned all the burs off with a dremel tool.

 

Put it all together with all 6 new clutches and no shims. Dipped each clutch part in diff oil.  Wet test in the vice was 45# with both a breaking-style torque wrench and a wand-style torque wrench.  Breakaway was 45 both with and without the ring gear on and torqued.  Slapped it into the case, added 2 tubes of Trans-X and a quart of synthetic 75W-140 oil.  Put an Energy Suspension insulator on the front awaiting a new RT mount.  Diff cover is tapped for an NPT 3/8" fitting for external venting to a puke tank.  I think the problem was a combination of using too many stock discs to the point that there was more added total clutch thickness than the thickness removed by removing the spacers, and possibly burs on the clutch discs. Thanks everybody, especially for encouraging me to not give up.  Mission Accomplished. 

post-5903-0-76742800-1357099682_thumb.jpg

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