j_tso

iTrader: (2)

In other words, your crush tube hasn't been crushed yet.

Like peejay says, it takes A LOT of torque to crush it down. However, once you start reading a little lb/in for preload proceed very slowly because if there's too much you need a new tube.

Thanks for the offer on the gears, but I'm going to have another spare when I pull the one that's in the car.

Edit:
While it does make sense to crush a new sleeve to get the right preload, you might save yourself a sore arm by using the old one. The manual says if you can tighten the nut 94 ft/lb (up to 130 ft/lb) and reach the correct preload you're good to go.

GSLSEforme

There are 3 crush collars at play here. The original one from RX differential. The original one from the Miata differential and the new one you purchased. 2 used and 1 new.
New is 57+mm. Which is the one that you have measured? at 56mm,the one from RX diff or Miata diff. Are you using the newly purchased crush collar in pinion assembly you have currently put together? If this is the case,the responses of the previous posters is correct.
A subtle shortcut i use on these and other brand of diff setups that use a crush collar is to put the new crush collar in a press and begin-just begin-the deformation process there.

The initial deformation of crush collar is what takes the large amount of torque on all crush collars not just the brand you are working with. Further tightening of pinion nut on assembled pinion parts in diff will now only require @1/3 amount of torque to further crush the collar to proper pinion bearing preload and greatly eases the tightening/checking tightening process to checking pinion bearing preload. These crush collars are one time use only. If you are currently assembling the pinion setup in diff housing to then install assembled carrier/ring gear to check gear contact pattern and it's not correct,you will need another crush collar to do final assembly. Technically,you will need a new crush collar for every adjustment you make to shimpack to get tooth contact pattern correct.

I suggest you currently tighten the crush collar only enough to take up all play in the assembly and feel just the slightest tension on the bearings as you rotate pinion. This will be easier as you don't have installed pinion seal lip to add to turning torque.Use a copper hammer or block of wood and smack end of pinion in diff housing once and same for companion flange to seat bearings in races and recheck "feel" of turning resistance. If it now feels looser having done this,slightly tighten pinion nut to regain same level of turning tension of pinion
Assemble carrier/ring gear into diff housing,adjust backlash to spec and put gear marking compound on ring gear and check contact pattern. If it's perfect,great,if not disassemble to increase/decrease thickness of pinion shimpack as necessary. Measure length of "crushed" collar 56.80mm is minimum length spec,if you only lightly tightened pinion bearings the collar will be longer than this length and can be reused. If not you need a new one.

Removing pinion to adjust shimpack for proper tooth contact may damage(likely) both pinion bearings and why i referenced "setup bearings" in a prior post.

Regarding solid shimmed spacer in lieu of crush collar,i mentioned this in same prior post. To get the dimension for installed shimmed solid spacer,use the dimension of final assembly crush collar length minus a slight amount using combination of shims supplied with solid spacer and assemble pinion into diff housing and tighten pinion nut and measure turning resistance/torque and add/remove shims to get required pinion turning torque . I like to assemble new pinion bearings to higher end of turning torque specs. This spec and solid spacer will keep proper pinion bearing preload longer and keep differential in spec longer under hard use.

Holdfast

I torqued it down to 130 that the max the factory manual said to go. That made my new crush sleeve 56.8mm. The 55mm crush sleeve. Was out of the rx7 pinion. Its too short. The miata pinion didnt have a crush sleeve or front bearing when i bought it off ebay. I torqued it down but didnt want to crush it past the 56.8mm. Then i would have two 55mm crush tubes that are too short. With the 56mm crush tube in there i cant get any tension on the bearing. The min length is 56.85 my old rx7 crush tube is 55.7 i put the old 55.7 in there and it has perfect tension. I

GSLSEforme

What is your turning torque,lbs?
Are you assembling differential to check tooth contact at this point?

GSLSEforme

Look into Weir Performance for crush sleeve eliminator kit. I have used their products several times with good results.

Holdfast

i just got the diff bearings in today. So thats next. First. Im going to the gm dealer to get the gear contract paint. The spec limit for the crush tube highth is 56..8. Thats where im at with my new tube after i torqued it down to the recommended max 130ft pounds. But i could still lift up on the pinion shaft. The old one 55.7 installed it has tenion on the bearing. But dont wsnt to use that one because the pinion was too far forward and the wear pattern was on the outside tip of the ring gear.. So im going to ge with the 56.8 crush tube and see how the pattern looks

j_tso

iTrader: (2)

Tension on the bearing is preload. If you can't turn the flange there's too much. You need to measure how much torque it takes to turn the pinion with an in/lb torque wrench.
The crush sleeve controls the preload.

The shim pressed between the pinion gear and inner pinion bearing controls how deep the pattern goes.

GSLSEforme

It needs to be understood that pinion depth is set by the thickness of shim between pinion and rear pinion bearing.
The crush collar only sets pinion bearing preload. The dimension of the crush collar is secondary to the in/lb spec reading when turning the pinion. Likewise the 130 ft lb tightening spec is the minimum tightness the pinion nut can be. It takes more force-and higher torque to crush the collar to achieve correct preload. Correct pinion bearing preload is what you’re trying to achieve here.

Did you change the previous”new”pinion bearing races and install the races in diff housing that came with your latest bearings?
If not you should,they might be dimensionally inaccurate as the previous bearings were.

What you are trying to achieve at this point is tightening pinion nut to just past the point at which there is no in/out movement of pinion assembly and a very slight amount of drag.
You are only setting up for pinion depth readings and full pinion bearing preload is not necessary at this point. You want the pinion assembly to have no movement other than rotational.

Reread my original post,I know it’s long but it contains these details. Also note it says to use the used crush collar if possible for setup as you only need it to take up space to bring pinion assembly up to tight enough there is no in/out movement-only rotational.

The crush collar is a one time use piece and why I said to use the previous used one for setup. You will need to purchase another for final assembly.

I don’t make a practice of pressing a new pinion bearing off to change the shim(s) and pressing it back on again. Seldom can this be done,no matter how careful you are,without binding/distorting the new bearing.
This is mentioned in my 1st post also regarding “setup” bearings. The good quality bearings you are going to use on final assembly are only installed after pinion depth(tooth contact) is known to be correct.

By now you are understanding why crush collars are a pain in the ***.

If you were going to install a solid spacer,it is now when you substitute it for crush collar before final assembly.
Measure length of crush collar and select supplied shims of enough thickness(that came with spacer) that make length of spacer+shim(s) to be slightly longer than measured crush collar and install pinion assembly and tighten. Tightening of pinion nut now is not as crucial as previously as you’re not trying to achieve preload by crushing spacer as you were with collar. Proper pinion bearing preload is determined by spacer shim selection.
Test turning torque of pinion,carrier/ring gear not yet reinstalled-you are measuring pinion bearing preload only.
My preference is to setup preload on the tighter end of spec. As long as you are within preload specs you are good. Remember to add 1-2 in/lb for drag of not yet installed pinion seal to total preload reading.
Example: if your installed selected spacer shim(s) brings your turning torque reading in at low end of spec,installation of pinion seal will add 1-2 in/lb to that.

Hope this is helpful and not adding to any confusion you may have.

Holdfast

I used the races that came with the bearings. I just kept tighten it till i had no up and down movement on the pinion. Then measure it with the inch pound torque wrench. After that everything else went together with no problems. The pattern looked good so i didnt have to change shims. Bearing preload on the diff side bearings was tedious. Keeping the back lash in spec at the same time. Had to buy a cheapo 12inch calipars to get the bearing caps within specs. Putting it in now.

Holdfast

Does anyone make new axles for the 84-85 GSL ? My splines on the axles have a lot of play. I thought it was to much backlash on the R&P. So before i went any further i took it back out to double check. Everything was ok. Would i have to replace the spines in the diff also?

GSLSEforme

What's mileage on your car,was the differential in the car prior to your swapping ring and pinions original to the car? Did you have these"play" complaints prior to your swapping ring and pinion gears and bearings or is this something that has occurred since reassembly as you make no mention of this condition prior to diff work.

The work you did would have no bearing on the play you say you now have in axles. The splines? in the diff you refer to are called spider gears,2 pinion and 2 side gears. They and the axle splines will have some play. The spider gears have shims and specs to adjust the clearance in them. You make no mention of disassembling LSD unit to check any of these parts. Has this car seen any time on dragstrip with slicks? The engines in these cars don't develop a lot of torque load on differential parts on launching in stock configuration. V8 engines are the opposite of a rotary engine in this regard. Never seen axle splines worn enough in a stock car that needed to be replaced because of wear. In your case,you had the axles out,twice now, did you happen to pay attention to wear pattern in splines while out of car?
I have twisted and broken axles in 1st gens but only with repeated dragstrip abuse. "Normal" street driving does not wear parts like this.

Until you respond here,i surmise there's something amiss with parts replaced and their setup.Couple Questions...
The play you feel-when driving car- is when you shift,let off gas then initially accelerate again?
Is the gearset quiet on accel/cruise/decel or some noise?
What was actual final pinion bearing preload #?
What were ring gear backlash readings,did you check ring gear in 4 locations,and average these readings? What were 4 readings and your average?
Did you preload carrier bearings and check ring gear backlash afterwards?

Holdfast

I did have a lot of back lash before i started the r&p swap. But thought it would be gone after i rebuilt it. I did look at the splines when the axles were out. They are worn but still looked good. My back lash i measured at 4 points on the gear .06mm. The rear end is not tbe original. I got it from the junkyard about 3-4 years ago it had 110k on the car when i got it. There was nothing wrong with it other than the backlash before i swapped the 4.10. I do drive the hell out of it. Rear rims are 7inch wide with some good Dunlops 205/50/15. Car dyno at 200hp but i got a lot more out of it after it was dyno on my own playing with the tune. So i know its over 200hp. I checked the back lash after side bearing preload of 185.40mm measured across the two bearing caps back lash was .06mm.. Not right away i had to play with it for awhile before it was all set right.

GSLSEforme

I think you need to revisit LSD section of rear diff and check spider gears for wear and see what oe shims measure at. If spiders are not excessively worn there are a range of shims from Mazda that can tighten them up
A fair amount of slop in driveline can be found here.

What was your final pinion bearing preload?

Holdfast

It was worth all the trouble putting that 4.10 r&p in. After finally getting the right axle seals and rebuilding the rear calipers. I got it going again and boy does it GO!!. This car hauls ***!! The gears ratios of the miata gearbox are perfect now with the 4.10. Amazingly it has no gear whine or problems so far. I highly recomend the 4.10 r&p with the miata gearbox to anyone thinking of doing it. Its perfect for a street car. I think a lower ratio like 4.33 or 4.77 would be too low in a street driven car. I think i will need to rebuild the lsd in the near future. I tried to take it apart but couldnt get the Phillips head screws off. I stripped one trying. Thanks to everyone on here for all the advice getting me through it.

jes

you can use the pumpkin with some mods & driveshaft... you will loose spine engagement depth unless you use custom axles...
towards the bottom of the page I have pictures related to the rear end...:
https://rx7-gsl-tii.us/TIIswap/

Holdfast

Nice car. Was it a big hassle getting it the bar certification? I almost did that myself. Was going to swap the whole engine and harness from a s4. But once i got the harness and saw the size i changed my mind. i dont have to smog now that i have it registered in the sticks. Do u still drive your car ? Im out in east bay area.

jes

It takes patience & perseverance to get the BAR label, it's been a while so I don't know if things are any different now. Advice from a friend that I agree with, change as littlte as possible before getting the label... also don't use any thing shiny. smog techs seem to be like crows, ooooo shiny, where's the EO #? I used brass tubing for a vacuum line & made the mistake of polishing it, FAIL! yes I still drive the car on special occasions, but it's realistically a garage queen... last trip was to an autocross, next will be freeway warm up on the way to smog test... I was at SS21 last year.

Holdfast

lol ive heard that before.. I was able to avoid that hassel by registering the car up north in the sticks at my parents house where there's no smog required. My goal is to eventually go to a track day or autocross to see what the car can do. I entered that new time attack event at thunder hill few months ago. But my miata/fb transmission had to be rebuilt.