Shimming the R200 Clutch LSD

[Ezzie]

Has anyone ever shimmed the R200 clutch type LSD diff from the '88 300ZX Turbo for a higher breakaway setting?? I think stock it is rated at 47 lbs. of torque. If so, how did you go about it. I looked up the P/N's of all the bits in the clutch pack for both the Z31 and the R32 on Nissan FAST JDM and it looks like the R32 diff (short nose) uses an extra friction disc on either side as compared to the Z31 variant (long nose) but they are the same P/N. The Nissan Competition CLSD retrofit is also different (uses a spring disc instead of a diff spacer at either end of the pack).

[JMortensen]

http://forums.hybridz.org/showthread.php?t=92629&highlight=shimming+r200

 

Try the search function. Looked up "shimming r200" and found my old post.

 

If you need the pictures PM me, but there should be enough there without the pics to let you know what needs to be done.

[CruxGNZ]

Jon, if you have pictures, post the links to them in your thread that's mentioned above. Visual learners, like myself, would appreciate it.

 

!M!

[JMortensen]

Well I guess I don't have them anymore. I checked but couldn't find them on my hard drive.

[Ezzie]

My objective is to do a mod to the stock 300ZX CLSD to get more durability and a slightly higher breakaway torque (65 lbs. seems about right for my application). The 300ZX diffs. I have bought used and taken apart all seem to have failed first by burning out the single friction disc on either side of the pressure rings. By looking at the Nissan Competition AND the stock BNR32 (Skyline GT-R) setups of the R200, they seem to be using 4 friction disks (2 on either side of the pack) instead of the 2 (one on either side). Both of the "street" versions seem to use a different part for the friction discs and plates as do the Nissan Competition ones.

 

300ZX:

Qty Part #

4 38432-N9000 friction plate (?mm)

2 38433-N9000 friction disk 1.75mm

- or alternate -

38433-N9001 friction disk 1.85mm

4 38435-N3210 spring plate 1.75mm

2 38437-71S00 diff spacer 3.2mm

 

BNR32:

4 38432-N9000 friction plate (?mm)

4 38433-N9000 friction disk 1.75mm

- or alternate -

38433-N9001 friction disk 1.85mm

4 38435-N3210 spring plate 1.75mm

2 38437-71S01 diff spacer (?mm)

 

So it raises these questions:

 

1. What are the differences between the 38432-N3210 and 38432-N9000 friction plates? (BTW - the N3210's are cheaper than the N9000's)

2. Ditto for the 38433-N3210 and 38433-N9000 friction discs?

3. If I were to add the extra 2 friction disks to the 300ZX pack - I would also have to change the diff spacers to the BNR32 one as well?

4. Is it better to have 4 friction disks (as used in the Nissan Competition and Skyline BNR32 clutch packs) as opposed to the 2 only used in the 300ZX pack?

5. And if so, why??

6. Would I be able to get about a 65 lb. breakaway if I merely subbed in the thicker friction discs (either the N3211 or N9001)?

7 Neither the 300ZX nor the BNR32 use the spring discs (38436-N3210) in their packs like the Nissan Competition ones do - instead they seem to use the spacers. Is this to get enough room for the extra discs and is this better?

 

Anybody know the answers to any of these questions??

[JMortensen]

1. I'd wager a guess that the N9000 plates are the ones with the grooves and the N3210 is the flat one like Mat had in his diff. That parts list is totally different than what I got from Nissan when I asked them so I can't say for sure, but your list does match what was in my diff. The grooved discs are going to hold oil, which should help them run cooler and chatter less.

 

2. Same as 1.

 

3. Yes.

 

4 and 5. Using the spacers doesn't seem like a good idea to me, because all the limiting of the slip is done by one disc and 2 plates. If you spread that work (and heat) through more plates they should last longer. As it is people are getting many years out of the 300ZX LSD without a problem, so maybe this is making a bigger deal out of it than it needs to be, but theoretically more discs = better.

 

6. First things first. Measure the breakaway as the diff sits now. VERIFY that the parts match the parts list. My diff matches your parts list, but Mat's doesn't match ANY parts list I've seen so far, and Gordon shared his experience of pulling open a Nissan Comp diff and having it be the same as mine inside. What you need to do is add thickness to the clutch stack to increase the breakaway, so yes, adding thicker discs will increase the breakaway. Notice though that I got from ~10 to 45 lbs by adding .020" shim, and when I added the 5th shim it jumped from 45 to 100. So adding the .1mm thicker disc is the same as adding the last .004 shim. If you are actually at 45 lbs breakaway and you remove the standard thickness disc and replace it with the thicker one, you should end up ~100 lbs. The other thing you can do is put a .002" shim on one side or the other.

 

7. The ultimate end goal is to not spin a tire. More clutch stack thickness = more lockup. More spring tension on the stack means more BREAKAWAY, but not more lockup. So by making the stack thicker you'll be less likely to spin a tire. By adding more springs and not increasing the stack thickness, you might just cause more understeer by making the diff more resistant to slippage, but not really add any lockup at all.