Diy:diff Shimming For R33 Gtst

[Rolls]

can do just as good ones with less understeer and discomfort if the preload is just set correctly, drive like a stock LSD and lock up under power every time.

just all these stupid wannabe drifters that think the more locked it is the more sick it is

Edited January 28, 2011 by Rolls

[ClutchBurndout-:(]

lol i know right, oh wells, ill have to live with the "wanna be sick doriftor" spec diff then untill i find another stock one

[Rolls]

It is just shims, they can be easily removed or changed. No need to find a whole new diff.

[ClutchBurndout-:(]

It is just shims, they can be easily removed or changed. No need to find a whole new diff.

im no mechanic, with my luck if i did the above tutorial, something bad would happen and id be without a car lol, wanna do it for me?

[Rolls]

hence me suggesting going to a diff guy, won't be expensive

[ClutchBurndout-:(]

ill check it out

cheers!

[brother_david]

just buy them from Nissan, like $6 or something, pretty sure the metal would cost more than that if you made them yourself, plus there's a possibility of stuffing it up.

A friend of mine works at Rolls Royce Marine so i would put him on the job, also when i was going to order shims for the valves on my RB26 head they said it would take up to 2 months to get it to Sweden. Ended up with ordering them from RHD instead, at 1/4 of the price too.

So no one knows the dimensions?

[Rolls]

call nissan, they probably know lol

[brother_david]

Haha they should anyway

[SargeRX8]

How do I tell from the outside if my diff is shimmed? Would both half shafts turn the same way if I turn them via the half shaft? An open diff will turn in opposite directions when a locked/shimmed diff botht turn the same way.... Correct?

[W0rp3D]

How do I tell from the outside if my diff is shimmed? Would both half shafts turn the same way if I turn them via the half shaft? An open diff will turn in opposite directions when a locked/shimmed diff botht turn the same way.... Correct?

You can't, any LSD or locker should spin the same way, if they turn opposite then you know it is screwed and needs shimming, if there is fresh red/orange gasket goo used on it then it will be a sign that it has been opened but it may have been rebuilt.

[Rolls]

You can't, any LSD or locker should spin the same way, if they turn opposite then you know it is screwed and needs shimming, if there is fresh red/orange gasket goo used on it then it will be a sign that it has been opened but it may have been rebuilt.

Pretty sure an open diff will spin opposite ways.

[tm_r33]

yer rolls your right mate. open difff will turn each half shaft in opposite directions. a worn lsd with fark all pre load will do the same thing.

a shimmed diff with a jag load of preload will turn both half shafts in same direction

[Bauerpower]

For the first time in its life my 33 has finally seen some decent hp after a turbo upgrade (gt3076 on 20psi) and an ecu of course. Not to my surprise the LSD had no chance at doing its job and started to 1 leg it everywhere. After reading the instructions on diff shimming thort I would give it a go until I got the diff apart and discovered what the shims do. I probly should have read a bit more into some of the posts. Nonetheless something needed to be done and I disagree with mashing the spider gears together. So I grabbed the viscus clutch and set to work.

Started by cutting open the clutch in the lathe. I cut down the center of the weld. Once open i could see I was slightly off target. Find the center then move half a mm left would be the gun place.

Pretty easy to see why It wasn't the best it could be. Silicone oil can get diluted easily, especially from wearing plates.

Quite a simple device realy. 2 banks of plates. one set driven by the inner spline and one by the outer consecutively placed one after the other. Cant remember the exact number but its about 50 plates all up.

The inner plates have a spacer ring around the outside to ensure the plates never touch.

Once all the plates were removed and cleaned it makes it a bit easier to see.

I got onto an online rc car store and purchased a jar of 300000weight (not a typo) silicone diff oil. Its the thickest they had and also comes with a warning not to use as a personal lubricant. Bummer.

Takes a while for the bubble to reach the other side.

Tomorrow I try to get it all back together again. I will post up more and the results soon.

[SargeRX8]

Is that an Active LSD?

[Bauerpower]

Is that an Active LSD?

No, its a standard LSD clutch from an r33 gtst. There a sealed unit. Until I cut it open anyway. Active LSD's are an ecu pressure controlled clutch pack and was a factory option fro the gtst and came standard in the gtr v-spec. Viscus LSD's rely on a large amount of surfaces area with an extremely thick oil between them to create resistance. The faster you turn it the more resistance you get and even more if you step up the grade of oil.

For active LSD info go to Active LSD Information

Edited April 15, 2011 by Bauerpower

[datsun_1600]

Awesome work there man - it'll be really interesting to see the results.

Jeff

[Bauerpower]

The clutch had to be assembled a bit differently then planed. Originally I was going to assemble the unit dry then using a syringe inject the oil through one of the holes (I knocked the balls out and drilled and tapped them) but the oil proved to be way too thick for that. So I assembled it wet and altered my welding method.

All parts ready to go.

A very slow process, spooning oil in with a small flat blade(use anything the shit is that thick) and then firmly pushing the plate down.

You may have notoiced the blue dots. The plates do have notches in them so I decided to use them. Every plate I put in I made sure it was 1 spline to the left of the previous plate. I imagine if they were all lined up it would become very notchy in its operation.

The last 6 plates I stopped adding oil for 2 reasons. Firstly to keep some oil away from the weld and secondly to leave some space for expansion. There was some air pockets when I took it apart so I thort I better do the same.

Used the shaft to align then tack in place.

Welding became tricky as I didn't want to burn the oil or melt the seals in the center. So I just welded 1/8 section at a time then allowed it to cool.

Once together the difference is immediately noticeable. Before i could insert a shaft into the spline and turn it easily by hand. Now I have to put the unit in the vice and turn it slowly with a lever. I cant wait to get it in the car and test it, hopefully today if I get my sump back on in time. It was one legging stock size street tiers before and I'm putting on a pair of 18x9 slicks for the test. Should be interesting.

[datsun_1600]

Are you using a mig to weld it back together ? Sweet pics mate.

[Bauerpower]

I used the tig for that one, it sits neat in the center so I tiged it to minimize grinding. Sorry, I forgot to take a pic of the finished product. I was gonna test it now but there's a bit of rain around so no slicks. Feels reeely good though. I got my mate on one wheel and me on the other and we were struggling to overcome the LSD but it does turn slowly.