Quaife LSD Installation in R180 - With Questions About Installation Also

[inline6]

I have been rebuilding my differential for the last couple of evenings.  It is a "K" R180 from the front of a Nissan 4X4 truck.  From running it in my 240z, I know it was in good condition before disassembly.  And, when I took it apart, I checked backlash and it was within spec.  So, I don't believe it ever had been apart before.
 

I purchased a Quaife LSD for it.  I also purchased all new bearings and seals.  

For the differential case and the drive pinion shaft, I was very careful to install races and the tapered bearings, fully seating them in their correct positions.  I also was sure to use the spacers and shims that were removed back in their original locations.

Using old bearing as an installation tool for the front pinion bearing.

Using a homemade tool to hold the pinion from turning while setting the torque to 135 ft-lbs (factory manual specifies 122.9 -144.6 ft-lbs_

 

To get the Quaife in the case, it was required to "Fettle":

 

 

It took a lot of fettling, but I very carefully ground only where needed until the carrier just fit. In fact, I had to leave one of the main gear bolts off until the carrier was partly in the case, and then torque that last bolt through the side axle opening.  This fettling was an unpleasant surprise that added 4 hours of time to grind on the case.  I had to be extremely careful with packing the case cavity and other preparation to keep the metal shavings from the carrier and from installed pinion shaft (and bearings).

At this point, and here is where I stopped, I have installed the side retainers, left and right, with their respective shims in their original positions, with the 5 bolts on each just snugged down, not torqued.

 

 

Now, I could use some guidance.  

What I have not done that I may need to:

• I didn't measure the amount of turning force on the pinion shaft.  I don't have a suitable tool to measure that.  I see that this is supposed to be done without the pinion seal installed.  I have already installed that.  There is preload on the pinion bearings - I can tell by rotating the shaft by hand.  I just don't know how much.
• I did not remove the fresh paint (and primer) from the sides of the case where the side retainers seat.  I am wondering if those thousandths of an inch matter.  Given the side retainer shims originally used are quite thin, paint in this location may be an issue?
• I didn't measure the amount of main gear backlash with a dial gauge yet.  I just moved the main gear by hand back and forth.  Doing so, the amount of movement is noticeable.  I'd guess .015" to .020".  

I do have a dial gauge and magnetic base and plan to measure the back lash when I pick back up on this.  

I was hoping, perhaps naively, that I would be able to use the existing pinion and side retainer shims even with replacing the stock carrier with the Quaife LSD unit, but it looks like I have more work ahead of me.  The factory shop manual is difficult to understand, and I don't have the factory tools being referenced.  

Anyone have any guidance on how to proceed?  

I am thinking about buying the tool to check pinion turning force.  I am thinking to not removing the pinion seal, because I would likely destroy it in the process, but instead just factor in 1-2 additional inch-lbs into the reading I measure from having that in place.  So, if I measure 2 inch-lbs more than the factory upper limit, I'd call that good, for example.  

I am also thinking about removing the paint from under the side retainers and reinstalling them with fasteners torqued to spec to check the main gear lash measurement.  From there, I may need to order various side shims and attempt to get back lash correct?  Then check the gear mesh pattern to see if everything is set up the way it should be?

 

 

Edited September 15, 2023 by inline6

[Yarb]

I think you have done a remarkable job so far. I wish I had the expertise or could point you to someone that who does. Best of luck. There is an answer out there.

[Patcon]

I can't answer most of your questions, but I do think you are correct to remove the excess paint

[SteveJ]

You may want to search around Hybridz.org to see if any of your questions can be answered there.

[zKars]

There is a gentleman named Sal Ceja on several of the FB Datsun groups that sells shims for our diffs. He may also be able to supply technical help. 

[inline6]

On 9/15/2023 at 9:17 AM, SteveJ said:

You may want to search around Hybridz.org to see if any of your questions can be answered there.

Thanks, I found some relevant posts.  One of the frequenters of that site said, "It's been my experience that the backlash doesn't change notably. It changed .0005" on my own diff, and I've never come across any posts from someone whose backlash needed to be readjusted after installing the LSD."

On 9/15/2023 at 8:41 AM, Patcon said:

I can't answer most of your questions, but I do think you are correct to remove the excess paint

Before disassembling to remove the paint from under the side retainers, I measured the back lash, and it was about .014".  The factory spec is roughly .004" - .008" (the factory service manual is not near me right now).  I then removed the side retainers and scraped off the paint with a razor blade, and reassembled.  After doing so, I put the side retainers back on, snugged the 5 retaining bolts, and measured back lash at .020".  That was surprising to me, but I figured maybe I didn't measure it properly the first time.  

The factory workshop manual says that if there is too much back lash, to move shims from the left retainer to the right retainer.  As assembled from the factory, the left retainer has one shim that I measured at .011" thick.  The right retainer has two shims, one is .016" and one is .020".  So, I took the side retainers off again and moved the shim from the left, and stacked all three on the right.  I reassembled and measured back lash at .012-.013".  

Darn it.  

I found several pages back in this build thread, where I measured backlash before disassembling this diff, and it was .005".  So, referencing the info from the Hybrid Z post, I appear to be in an unusual situation where swapping out the open carrier for an LSD has perhaps changed things substantially.  Of course, in this instance I changed pinion bearings, so perhaps the pinion height has been altered now.

As a next step, I will measure the turning resistance on the pinion shaft to rule out that I over torqued the pinion nut and have too much pinion bearing preload.  I ordered a torque wrench which should allow me to check that properly - it will be here Monday.  However, I don't have much hope that the amount of preload on the pinion bearings is my problem. 

Doing something other than using the shims that came with the differential is a departure into the wilderness - this is not something I have ever done before.  So, I really am feeling lost about how to get this diff set up properly at this point.

  

 

 

 

[Patcon]

I wondered if the bearings could change the backlash?

[inline6]

I have some gear marking compound coming also.  I plan to check rotation torque and adjust if necessary by backing off the pinion nut a bit and retorquing.  Then, I will assemble the carrier in place again with no shims on the left and all on the right.  I'll check back lash for kicks (because I am sure it won't change).  And then, I will put the gear marking compound on and see what's what.  My guess is that the pinion height has changed, probably due to differences in the pinion bearings.  

I don't know how (at the moment) to figure out what to change with the pinion shims.  I will research.

Edited September 17, 2023 by inline6

[inline6]

I measured the turning torque on the pinion nut tonight.  Factory spec without the oil seal is 7-10 kg-cm without the oil seal in place, or 6.1 to 8.7 in-lbs.  I measured 15 in-lbs.  I think that is a bit much based on a Youtube video I watched, where before installation and after installation of the pinion oil seal, the turning torque was measured at about 14 on an R200.  

I will back the nut off some, torque the nut to the low end of the factory range instead of 135 ft-lbs, and re-measure.  Will try to get it to be around 10 in-lbs.

Edited September 20, 2023 by inline6

[inline6]

Tonight I backed the pinion nut off and reset torque to the low end of the specification.  While I had done 135 ft lbs before, I did 124 point something this time, just a couple of ft-lbs above the 122.9 minimum spec.  Interestingly, the inch-lbs of turning torque dropped from 14 to 10, which is much closer to the upper end of the turning torque specification.  Keep in mind that I measured this with the pinion seal in place, which is not how the factory manual calls for that to be done.  You are supposed to check the turning torque without the pinion seal installed in place, and then remove the nut, install the seal and torque the nut again.  

I think that is kind of ridiculous.  So, I am willing to gamble that the 10 inch-lbs I am seeing with the seal installed is just fine.

After doing that, I reinstalled the carrier and side retainers, and check the gear wipe pattern: 

front side of ring gear (first pic), back side of ring gear (second pic):

  

 

  

 

The first pair of pics shows where I applied the yellow paint directly to the ring gear.  I went back and forth through that with the pinion gear to get the first set of impressions.  After that, I kept rotating the pinion gear around until the paint that transferred from the ring gear to the pinion gear made another set of marks on "clean" teeth on the ring gear.  The transfer of paint from the pinion to the clean teeth on the ring gear is captured in the second pair of pics.

What I see is "toe" contact on the coast side of the ring gear (first pic).  And I see heel contact on the drive side of the ring gear (second pic).  According to the shop manual, I will need to "increase the thickness of the drive pinion adjusting shim and washer so that the drive pinion is moved to the drive gear".

As I see it currently, I'm going to have to remove the carrier from the case (which requires removing one of the ring gear bolts in order for it to clear the case), and to remove the pinion gear, and bearings so that I can add a shim of unknown thickness to shift the pinion gear towards the ring gear.  If I guess wrong on the shim I install, then I won't know until I assemble everything again.  If wrong, it all has to come apart again.  I guess again... rinse repeat... I think I see hours of time and frustration for this little project in my future.

Anyone have factory tools for me to use to get this thing set up properly without a bunch of hassle?  Or ideas for how to save that time and hassle?

 

Edited October 20, 2023 by inline6

[dutchzcarguy]

Maybe you could put a picture here of the tools you need?  Maybe someone has them but does not know that they are the needed ones? 

I follow your work on this because i recently bought a diff in parts with new bearings.. and.. i have to put it together some time (i guess job 2987 that i need to do some time..) 🙈

Before i bought it i looked it over how to build the diff .. i remember something like you have to paint some teeth and let it drive the other teeth over the painted ones and look at the "dents" in the paint.. not at what the paint does to the clean teeth.. ??  In pic 1 is that with the indents? They have to be in the middle of the teeth's so it's not a bad start..

You need a small shim to correct it to the middle, i think there is a way to determin on what side you have to ad a shim..   As i said i need to do this some time but also never opened up a diff.. it's interesting to see though..

Edit.. Also try to stop the outgoing axle when turning the ingoing axle (Maybe someone needs to help you with that) then you get better indentations in your (fresh thin layer of) paint.

Edited October 4, 2023 by dutchzcarguy

[inline6]

17 hours ago, dutchzcarguy said:

In pic 1, is that with the indents? They have to be in the middle of the teeth's so it's not a bad start..

You need a small shim to correct it to the middle, i think there is a way to determine on what side you have to add a shim..   As i said i need to do this some time but also never opened up a diff.. it's interesting to see though..

Edit.. Also try to stop the outgoing axle when turning the ingoing axle (Maybe someone needs to help you with that) then you get better indentations in your (fresh thin layer of) paint.

Picture 1 and 2 is using the standard method.  Pictures 3 and 4 is just my idea to see if it is any more clear to see the contact areas.  The pattern can be hard to see clearly.

For what it is worth... here are pictures of the tools for setting pinion gear (height):

There is a fake pinion shaft and a bar with square ends.

 

The plan at this point includes removing pretty much everything and pulling the bearings off of the pinion to get to the washer that is #1 in this picture:

There were no shims (#2 in the above picture) on this differential.  There was only a washer.  I need to measure the thickness of this and then either, add a shim (#2) of the correct thickness, or replace the washer (#1) with a thicker one. 

On Subaru websites, I see only spacers (#1) available:

https://www.subarupartwholesale.com/a/Subaru__STI/49247923__6023356/DIFFERENTIAL-INDIVIDUAL/G11-195-03.html

Nissan websites show both the spacers and shims as discontinued.

Edited October 5, 2023 by inline6