Jtuned_andy

I dont know how this can be considered an acceptable practice by any respectable car tuning community.

By incorrectly shimming the differential you are causing strain on the gear mesh. this will cause unnecessary wear on the gears, heat build up, and possibly failure of parts under certain circumstances.

if the engineers at the factory had thought this was a good idea, you wouldn't be hunting around on the internet for a $5 mod to lock up your differential better.

thats my 2 cents as someone who actually has experience working with differentials and transmissions

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Bambi

1. Welcome to Zilvia/the 240sx community.

2. Most people here just got a cheap J30 differential and haven't reported any extreme failure. I myself haven't heard of such a thing yet. Worst case scenario you drive home with an open diff vs. having a welded diff and not being able to go anywhere.

3. I don't understand what you're trying to get at with that statement. All of us do things to our cars that weren't intended to be done and that also harm or wear the car/part/system that is modded. Such as boosting a KA or going crazy with suspension mods to get more angle. Cheap diffs with a cheap mod to be most likely used to abuse the car itself anyways.

4. I respect your input but here, on this forum, the majority drifts and ruin their cars. :P

As for myself I'm just sick of an open diff, bought a VLSD for $80 and just want to get both wheels going.

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holslut s13

You really should go through all the pages of this thread before asking stupid questions that have been broached already. Me and other members have gone over shim sizes used in previous posts.. C'mon jus read bro

ov1989

sub'd i will need to look at this very soon

EvoVIII808

3 months into my shimmed diff. at first it was was full locked, and now its alot like a 1.5. No problems to date.

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Bambi

Okay. Thanks for posting your concerns opinions while providing zero help or benifitial input. I will now go read every page, every post, every paragraph, every sentence, every single word, and when I'm done I'll write a brief essay and we can go over it and you can let me know how stupid or well put together it is. We'll keep in touch, bro.

Nice! J30 or s13 VLSD? If you dont mind me asking.. Did you stack shims or just replace the one you had? You seem to have the effect/setup I'm trying to go for (1.5 or close to and NOT a 2 way or welded feel). Just not sure of I should stave shims or replace what I have with one larger one.

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EvoVIII808

I have J30 with 1.01mm stacked ontop of the stock (1.27mm) It was fully locked for about a month but drives and feel alot better now. You also get alittle more noise from the diff but nothing bad. (i have everything stripped out so mine may be louder then others) Can see some of the info on page 5. took me about 2hr 30min to do. Was my first time so i took my time, measured everything, and checked everything twice.

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240SilviaX

Bambi, 1st off do you want to drift your daily or mountain/canyon run your daily? 2nd, the 240 and J30 vlsd unit is pretty much the same besides the ratio (ring gear) and the position that the vlsd unit inside of the case because of the thinner(240) and fatter(J30) ring gears so the bearing shims (look @ post #127, part 21) are used in different spots to make the ring and pinion mesh correctly (edit{ and the axle output shafts are different sizes due to the differences of ring gear thickness}). And obviously the casing is different due to the S14/J30/Z32 mounting style of the diff to the sub frame and the ABS sensor. If you want to drift look at Evo's and holslut's posts and you can find that their combos of shims make the diff lock up,, If you read my post #128 ill even copy and paste it for you,,>>"" my stock shim size out of my J30 was 1.13 and the other one around a .80. I think every J30/240 vlsd has its own diff sizes from the factory. What I did cuz I didnt want such an aggressive rear end (canyon/mountains) is measured the slack with the stock shims in place with a feeler gauge with the unit together. so there was .20mm in slack and I added up the 1.13 shim size and added .10 more for stiffen it up and got 1.43... 1.13+.20+.10=1.43 and conveniently there is a 1.43 shim and went and ordered from Nissan. I have only driven the car around the neighborhood with no chirping or ratcheting. Still need to go on a better test drive w/o a slipping clutch to get a better feel of this diff. plus I still have the other shim that I replaced and if needed to tighten up a lil more""..
Now I have driven this car with a brand new clutch with the shimmed vlsd for 2 months.. its nice, no grinding or chirping. will lock up most of the time on a wet surface not hard but just enough to get you sideways.. and I only added .10mm of shim after the slack was accounted for. I could of added more like .30mm over (not adding that size shim on top of another , ex, (stock shim[1 side] 1.13) +(.20 slack I measured with feeler gauge)+(.10 what I thought would be enough to tightened it up)=1.43mm which is nissan part # 38424-40F81 ..with a lil searching online you can find the 20 or so sizes/part# you can order from nissan.. If you have any questions you can ask me @ the Irvine meet .. Holslut has a valid point if you have read everything you would of noticed that everything in this post has been mentioned somewhere in this thread,, no need for attitude,, just sayin. hope this was enough info for you to start on your vlsd ..

240SilviaX

I wonder if KoolAidMan687 shimmed his bearings correctly or left it how they were with the J30 ring gear , cuz if he didnt shim the bearings correctly when using the 240 ring causing improper mesh or the ring and pinion are far apart from each other causing broken teeth leading to failure.. you got to make sure that your gear mesh is within spec or that will happen

Bambi

Yeah I plan on taking my time as well. Well thanks for the feedback, I've been writing out a couple notes and just added some of your info with sizes/etc..

Would like to drift my daily but if possible still have something reasonable to drive through a canyon without having the rear end trying to slide out. But again, drifting is the goal/priority so if a "happy medium" can't be somehow met a shimmed set up for drifting it is, just not all out aggressive. I would like to have something daily friendly and still be able to get both wheels going when trying to drift dry or wet. ...if any of that makes sense.


Anyways, being that I have an S13 VLSD I wont have to mess with the ring gear, output shafts, etc. That that would mean I'm really just taking it out, opening it up, checking which shim I have and then either stacking or replacing it with a larger one (all sizes depending on what I originally have), putting everything back together and done? And the shim to change/stack would be #17? (as seen below)




Also the only thing I don't think I totally grasp is correctly measuring the slack. I understand I'll need a feeler gauge to do so but that's about it. That threw me off a bit. I was thinking just taking the O.G. shim measuring it and then just finding out what size I'll need to stack on top of it and done? Having trouble visualizing it.


And you have 1.43 but that won't lock up very well right? So for my 'need' I believe would have to go bigger than 1.43 and more so into the realm of EvoVIII808 of 2.28 (1.01 + 1.27) or just barely below that.


And finally, thanks for putting up with my shit. I'll buy a drink or a snack or something from somewhere by the meet on Weds. You've been a great help with this.



edit: also this kind of goes for anyone/everyone to answer... did you guys go by factory torque specs when putting everything back together or just tighten it down to what you thought was good? i.e. using the numbers from above.

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240SilviaX

#'s 17 and 14 is what out need to measure.. the slack is what the vlsd has worn down between the shims and mating surfaces due to wear over the 16-20 or so years of use, you measure with a feeler gauge to get a measurement of what has been worn down. then you add that measurement to your #17 shim size then add about .30mm to .60mm to that and you can find your shim size or combo of shims to get to that size..

240SilviaX

always use factory torque specs.. very important,, been working on cars for a living since HS

Bambi

Ah! Okay NOW I get it. I'll be getting to work on it tomorrow, thanks again.

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240SilviaX

take pictures with your phone of the internals and the vlsd unit together so i can point out where to measure it... when you measure the slack sit the vlsd on the ring gear bolts side down (bearing on floor/bench) and you should see the the #14 shim and stick the feeler gauge in between the gear and shim or between shim and casing

240SilviaX

bambi ,, did u still need the ash tray ?? if so I will bring it tomorrow nite

Bambi

Alright will do. Today I didnt get to make any progress other than drain the diff completely and take the cover off and just as I did that I had to go to class so my day consisted of that and work.

And how much for that ash tray?

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240SilviaX

$10,,,,,,,,

Bambi

Alright cool with me dude

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240SilviaX

Jtuned_andy ,, do you really think drifting is acceptable practice by any respectable car tuning community?? dropping the clutch/ clutch kicking, slamming gears,, redlining for multiple seconds on end, burning your tires, yanking your ebrake causing flat spots and stretching your cables (if not hydraulic), smacking walls or flying off of course causing body damage ect.ect. I think over shimming a diff is the least of our worry's and its a cheaper solution to dropping a grand on a LSD that might break after heavy use?? $100 or $1000? your choice as it is ours ..

240SilviaX

PS I been a mechanic since my senior year of HS.. Ive worked at body shops, Midas/ exhaust , Firestone, some ma and pa shops, to building 600+hp dart block small block fords and Mustang GT's and Cobra's at my current job so ya coming from someone with mechanical experience I think its fine.. and if does break then Ill go pull another from the yard for $50

Bambi

Same exact story here, except it didn't go as far down as 1.25. Just between 1.27 and 1.30. I too also bought the 1.01 and a 1.49 (didn't/don't think I would use but still handy maybe someday) but being that we seem to share the same stock size shim and you ended up with the results I'm looking to get I think I'll follow in your foot steps and throw the 1.01 in there.

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EvoVIII808

just Remember It Will Be Full Lock atfirst

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Bambi

Yeah I understand, hopefully for not too long but I'm wiling to put up with it for a bit as long as the end result is what I'm hoping for.

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psychos13

how much life till it wears out?

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EvoVIII808

Unknown, i dont beat on my car much. Mostly drive it to and from work. It hasnt been on the track in 3yrs. so with daily driving im assuming it will last a life time.
And if the shim gets to worn down, open up the diff and replace it or buy a cheap diff and do it all over again.

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Bambi

Okay so today I made the first attempt at putting the VLSD into the stock/open diff. pumpkin...

After a few attempts, mallet, and a brass hammer I got in there all snug. By the look and feel of everything there seemed to be a good amount of backlash too. But after finding and using the dial indicator I found out my back lash was of by 1 1,000th so I took everything out to start over. It seems like I'll need the vlsd to be slightly more to the left to correct the back lash so I've taken my shims from both the original open diff. and VLSD diff. and measured all of their thicknesses with a micrometer. I'll be putting everything back in with a different combination of shims this time having a thicker one on the right side and a slightly thinner one on the left to get it to slightly shift the whole unit in the correct position to HOOOOOOOOOPEFULLY correct my backlash and bee within factory spec. Then I'll take some gear paint and check the pattern and if all goes well I'll have a perfectly functioning diff. without any whining and extreme wear.

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ghoti

The same as having and Un-shimmed diff. All shimming does is "engage/lock" the diff much quicker.

Life expectancy depends on how you drive your car.

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Bambi

No, not exactly. Yes to how you drive the car but for example the post I just made was on backlash (which is in other words, 'play'). If you have none at all or too much then you're going to advance the wear of the differential. And when I say no I mean more so that re-assembly is where you have to be worried and not so much on the actual shimming of the diff..


Now I know I did basically come off as "dgaf drift car bro" but in all seriousness yes, if you don't do this correctly you'll likely increase the rate of wear of your gears and possibly have a weird contact/pattern (which you can check by looking at the pattern that's already on the ring gear and using some gear paint to see if it has the same original pattern )and between them and you'll have that annoying whine x100000. And again, all this shit is cheap anyways so fuck it do what you want. I bought the s13 vlsd for $80 and the spare/extra open diff. for $10 so say I fuck up I wont be all that devastated.


Hope I made at least some sense, typing on a tiny iPhone 'keyboard' is a bitch.

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Daviticus

Wrong.

The "locking" everyone speaks of is the incorrect mesh between the spider gears causing an internal bind. This ACCELERATES wear on the spider gears and they will eventually wear thin, or break. Its' the same concept as the OBX LSD insert for open diffs - it presses outward against the spider gears and cause bind against the case, causing the desired lock-up.

But, like everyone has said, it's a cheapo diff, so no harm no foul if it breaks.

-edit-

Previous post in this thread as visual aid for my explanation: http://zilvia.net/f/s-chassis/200226...ml#post2992103

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- Welp, that blowed up real good. -

ghoti

Incorrect mesh between spider gears has to do with backlash, which is determined on how you put the washers back on when assembling the diff.

The "locking" happens inside the VLSD sealed unit.

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