How do I install a LSD carrier into a open differential?

[CruxGNZ]

Here's what I have:

-'78 complete R200 3.54 gears

-300ZX clutch type carrier

 

I have searched only to find posts that had no really solid information. I want to make my '78 R200 an LSD. So, I want a 3.54 LSD. I contacted Craig Taylor of Taylor Race Engineering, he was mentioned in one of the posts when I searched for this topic. Here's what he wrote back:

_____________________________________________________________

Dear Mat,

 

Thanks for your note.

 

I believe that you are indicating that you want to use the 300ZX dfferential

housing and LSD carrier, and to install the 3.54 ring and pinion into that

housing. Is this correct?

 

Assuming that the ring gear flange is in the same position for both

differentials (ring gear carrier), we would determine the setup of the ring

and pinion in the 280Z case, then remove that ring and pinion, and install

them into the 300 ZX housing. This also requires that the pinion shaft be

the same diameter, length, and spline in both housings.

 

Let me know if we can help.

 

Sincerely,

 

Craig

_____________________________________________________________

Well actually I wanted to use the '78 280Z housing with the 3.54 gears and install the 300ZX LSD carrier. Can this be done? I still have to write him back and let him know this, but I wanted to see if I can get some replies from you guys too. I am also a novice at rear end's, this will be my first one. So if you have any tips or tricks, please drop me a few. I know there are some sleeves to get around the 10 mm and 12 mm bolt issue, if need be.

 

!M!

[CruxGNZ]

Okay, I don't know how I missed this, but I searched again (very determined) with different search words and found this:

LSD carrier in open differential

 

Now the post by Mike C says that I need to check the backlash from the original 3.70 LSD gearset, but I can't, I only have the carrier from the rear end. How do I go about doing this? Do I just install the LSD carrier and then shim it to get the correct backlash?

 

Here are the parts I think I need to make this '78 R200 ready to run

 

1. New bearings for the carrier (can't remember the name of the darn things)

2. Possibly need shims from Nissan

3. A dial indicator w/ magnetic base.

4. LSD gear oil

5. New R200 seals.

 

Is this all I need?

 

Oh yes, I need to take apart the LSD carrier to clean it out (long story, had to do with shipping the thing) Anyone have any tips on cleaning this thing? Any parts that will fly out and scatter on the floor, leaving me to crawl around on my knees for hours?

 

!M!

[Mike C]

Mat, You only need to know the backlash on the 3.70 if you plan on using them again. If you are going to use the LSD in your 3.54 geared diff, check the backlash on the 3.54. Then when installing the new carrier, you want to get the backlash back to the same point. Check out http://www.mscdirect.com for a magnetic base and dial indicator for around $25.

 

LSD oil and non LSD oil is the same for domestic diffs. The difference comes with the friction modifier spec'ed by manufacturers to eliminate chatter. If your 3.54 open diff carrier bearings are in good shape, you can pull and use them.

 

I bought a Precision Gear LSD for my 3.54s. I'm not sure when I'll have time to swap them, but will pic document the swap when I do. I'm not sure yet, but it looks like an OEM shim setup from a 62-66 12 bolt Chevy might work in place of the Nissan shims. They use two small steel shims per side unlike the later GM diffs that use two large cast iron shims per side. The advantage to this is instead of buying shims one at a time, a complete set can be had for around $75.

 

I have not pulled a Nissan LSD apart, so I can't answer that!

[CruxGNZ]

Thanks Mike! I'll let you guys know if I run into any problems.

 

!M!

[zcarnut]

The LSD carrier housing length dimension will affect the pre-load on the side bearings. So, this will need to be re-checked, even if you re-use the side bearings.

 

The LSD carrier housing is under spring tension so after you unbolt it from the ring gear run bolts through two of the ring bolt holes and secure with nuts and washers. Then remove the phillips head screws that hold the LSD housing together.

 

Gradually loosen the two bolts you put in to relieve the tension. Reverse the process for re-assembly. The LSD shims, spacers and spider gears should be cleaned and inspected for wear. The shims and spacers go back in a certain order so mark everything!

 

There was a web site about re-building the Nissan Motorsport LSD used in the Roadster rear end (solid axle). However, this Roadster one is almost identical to the one used in the Z31, so the web site has some information on it. Do a search for it.

 

Still, the best technical reference is the 1988 or 1989 300ZX factory service manual.

[zcarnut]

I found the Roadster LSD site:

 

http://www.gordon-glasgow.org/lsdtech.html

[ecp48]

I have been researching this on a variety of sites. I can't remember where it came up, but supposedly the Late R200 differentials used a large diameter Ring Gear. This might screw up your use of the LSD in the early 3.54 housing.

 

I was looking at using the 300ZX Turbo LSD and my present 3.90 Gear set when this came up.

 

Other than what I've stated, I have no personal knowledge.

 

ecp48

[CruxGNZ]

Thanks for finding that web page Steve! Really appreciate that. I'm going to take it apart tonight. I am going to take pictures and make scetches along the way, so I can put it back together in the same order. Thank you for the tip on taking apart the carrier, should work out great the way I see it.

 

I have been researching this on a variety of sites. I can't remember where it came up, but supposedly the Late R200 differentials used a large diameter Ring Gear. This might screw up your use of the LSD in the early 3.54 housing.

 

So far the only thing that would stop me is the ring rear bolts. '84-'89 R200's use 12 mm ring gear bolts and earlier R200's use 10 mm ring gear bolts. I will need sleeves to install this carrier in to the early model ('78 in my case) R200. I think SCCA or Ross C had these offered on thier sites or I'm going to machine them myself.

 

!M!

[ecp48]

Thanks Mat73GNZ,

 

I knew I'd read there was a difference, but didn't realize it was the bolt size.

 

ecp48

[Mike C]

I bought a 3.54 diff from an engine fired 85 turbo. It had the 12mm ring gear. For $100 I figured it was a fair option to spacers. Noone is quite sure on when it switched from 10-12mm, but sometime between 83-85. 84 seems the logical conclusion with the model change, but you can't always apply logic to car manufacturers...

[Guest zfan]

I have wanted to do the same thing. I have a 300zxt 1987 r200 in my 71Z but like the 3.54 gears more than the 3.70's. It's always something

 

Mike

[dmanzo57]

I'm with Mike C on this one. I picked up a 3.5 open diff out of a '86 300zxt for $50 and swapped in the LSD unit. I used the shims from the LSD diff and the backlash ended up the same as before I started the swap, .007".

 

Don

[CruxGNZ]

Here is what I did. Instead of re-reading what was posted by you guys on here, I just went out and pulled everything apart on the R-200 3.54 differential, just to get things going while waiting for parts and seals to arrive. Once I get something in my head, like "pull apart differential", I'm on a mission to do just that, kind of like how Homer Simpson says, "Must find doughnut". After re-reading what was posted by Mike C

If you are going to use the LSD in your 3.54 geared diff, check the backlash on the 3.54

, I realized that I didn't do that, DOH!

 

So, now what do I do? Since my dumb@ss didn't check the backlash, how will I install this? When I pulled the R200 differential apart, there wasn't any shims. There was a bearing race (I left the race in) a large washer and then the oil seal on both sides. Was this washer a shim?

 

!M!

[spotfitz]

There was a bearing race (I left the race in) a large washer and then the oil seal on both sides. Was this washer a shim?

 

!M!

In a word, yes

[JMortensen]

If Mike C was right that 12 bolt Chevy shims will work, and you need to change the backlash, then you should buy some SuperShims. Instead of getting a stack of thin shims you get 2 thick shims (1 per side) that open up. Once open you can put the thin shims inside. This is advantageous because you don't have to fight to get a stack of thin shims in on the side of the carrier which is a real lifesaver.

 

If you buy 12 bolt chevy carrier shims from most people you will get a stack of shims in varying thickness. I think Mike C was thinking of factory shims. I didn't see anyone mention carrier preload, but you can also use the SuperShims to adjust that as well. You get the backlash right with 0 preload, then add .004 to each side so the backlash stays the same and the preload is there. Preload is absolutely necessary. Without it the ring gear will deflect away from the pinion when you put power to the diff.

 

You can get the shims from these guys:

 

http://www.ringpinion.com

 

They also have tech articles if you aren't sure how to measure, etc.

 

Jon

[Mike C]

The early 12 bolts, 64-67, use thin "washer" style shims like the Nissan diff. The later 12 bolts, 68 and up, use the stack of shims as mentioned above, and yes, the interlocking "super shims" are easier to use. But they won't work on the Nissan diff.

 

Mat, if you will measure the "washer" that came out of your r200, I will measure the OEM 12 bolt shims I have for OD, ID, and thickness range. You will be fine on setting up your LSD if you get the backlash into the middle of the recommended range as specified in the Nissan service manual.

 

I installed a set of used 3.42 in a '74 Trans Am last week. When I pulled the gears from an '87 Blazer, I marked the pinion depth but not backlash. I set backlash to the tight side of the range (I couldn't get it in the middle no matter how much I switched and shifted shims!) and it was smooth and quiet.

[CruxGNZ]

Mike, that's good to hear. All I have to do then is get it to within specs and I will be fine.

 

I will measure the "washer" and post the results when I get home tommorow (8/18 ). I'm in Joliet, IL right now at my buddies place. We went to see the Air and Sea show in Chicago today, man was that show awsome! Almost had 3 planes break the sound barrier. I have proof of this too, it's all on video, you can see the cone forming around the plane, it was too cool.

 

!M!

[CruxGNZ]

Mike,

Here's what I have, there is a total of three "washers" but I will call them shims from here on out. Here is the measurements I took. The thicker shim on the passenger side was to the outside, then the thinner shim inboard.

 

Passenger side

Shim #1

3 3/8" O.D.

2 3/4" I.D.

3/32" Thickness

 

Shim #2 (thick shim)

3 5/16" O.D.

2 9/16" I.D.

21/64" Thickness

 

Drivers side

Only shim

3 5/16" O.D.

2 3/4" I.D.

3/32" Thickness

 

The two shims that are placed against the case (furthest outboard) are somewhat puzzling. You would think that they should be the same I.D. and O.D., but I'm new to rear ends.

 

!M!

[RB26powered74zcar]

BTW, I have a couple diffs apart and in buckets if their would be a bunch of differnt thickness shims, I may have what you may not and vice versa....

just an offer, I have a dial indicator and could check for a size if need be...

 

j.

[Mike C]

Got home late tonight Mat, but I'll measure the shims for you tomorrow and post OD, ID, and thickness range.

 

I think the "bigger" shims are used to get the diff in the general range for a particular gearset, then a little shim is used to get correct preload. Most likelly you will just reinstall the shims that came out in the same spot. I have done gearsets in 10 bolts and re-used the GM cast iron shims with no apparent ill effects...

 

I have found that there is significant variance in the OD and ID of aftermarket shim sets, but thickness is the only real issue.