Shimmming Up The Viscous Diff Project Underway.

[CEF11E]

I have just picked up a S14 R200 diff with viscous centre and have ordered the OEM nissan shims and plan on removing the current shims and installing 1.01 mm ones (factory ones are 0.80mm) There are 2 shims in the LSD and this will take the total preload up .42mm offering a tighter than factory viscous LSD. you can install 1 shim plus the 2 already there bringing the total up to 2.40mm but you will basically have a locked diff and are risking the spider gears binding.

The LSD cost me $100 and the shims about $10 each. and anything has to be better than an open wheeling diff. I am not expecting a mechanical 2 way or anything but will be happy with anything better than current.

The Diff I have in my car at the moment has a 4.3 ratio and the diff I have just bought has a 4.08 ratio. I don't really want to pull my old diff apart and am thinking of just using the 4.08 pinion and ring gear. How much difference will there be? between the 2 ratios? I have never really understood final drive ratios.

Also can you measure nissan diff ratios from the number of teeth on the ring gear? the one I have just got has 37 teeth. I would really like to confirm it's ratio is 4.08. Can anyone in the know about ratios please comment.

Thanks!

I will post up the results as soon as it is in. I am installing it on the weekend.

I have heard some really good results and will keep you all posted.

[MANWHORE]

Got a q for ya. Are you going to be doing it yourself?

I'll be watching this carefully, because I've always been worried about doing the diff myself, because I thought it had to be aligned etc.

[CEF11E]

Yep, I will bo doing it myself. the Pinion and crown wheel have to be aligned.

Most diff places align it with a hammer!

[salad]

Not sure if this helps or not but this is the guide I used when I shimmed a diff a while ago

http://www.d1nz.org.nz/forum/viewtopic.php...a84e160bbe32105

There was only 1 factory preload shim in mine though (R32).

Here' a list of shims + prices that I found from another thread.

0.80mm = 3842440f60 price = $10.12

0.85mm = 3842440f62 price = $14.67

0.90mm = 3842440f63 price = $9.97

1.01mm = 3842440f67 price = $9.79

1.05mm = 3842440f68 price = $14.40

1.10mm = 3842440f70 price = $6.37

1.20mm = 3842440f73 price = $6.37

1.30mm = 3842440f76 price = $10.89

1.40mm = 3842440f80 price = $6.37

1.49mm = 3842440f83 price = $6.37

For a tight VLSD that's not locked, I would personally got 1.2 or 1.3mm shim without the stock shim. But I dont know, I havn't tried personally, just a guess. The one I shimmed up was for a guy that wanted it locked, so I put in a 1.49mm + the stock 0.8mm.

Using the different final drive will put your speedo out as the speedo reads off the gearbox and assumes a final drive rato. If you've got the whole diff, count the number of teeth on crown and divide by the number on the pinion.

You will have 5% less acceleration but 5% higher top speed.

Edited January 25, 2007 by salad

[CEF11E]

Thanks Salad,

yep. I have pulled the centre apart and found there to be 2 preload washers

1 on the onderside of the viscous centre and one on the other sode of the spider gears carrier ( opposite ends of the housing)

I found that when I put the second shim in the whole assembly would not screw down completly leaving a 1mm gap between the 2 halfs of the pumpkin.

Did you find the same thing?

[felixy69]

i made shims from metal oil cans "motul 300v cans"

stuck them one on each side of the stock bnr32 diff..i wonder how it's goingto work !

[Cubes]

CEF11E,

Could you count the spline on your half shafts (that slide in to the viscous hub)

I have a good tight VLSD Q45 Infinity viscous hub here that I'm toying with throwing in to mine for a quick fix.

Long story short I picked up what was supposed to be a GTR diff and axles, turned out to be GTR axles but with a Q45 Infinity vlsd centre and half shafts.

The Q45 Infinity runs the same half shaft/axle 6 bolt (1x6) pattern as the GTR. Unable to tell the difference until you rip the back cover off and notice its a VLSD unit.

I had a hell of a time trying to get the unit back in to the housing. :S

[CEF11E]

Let me guess? blocks of wood and a hammer?

sure will count the 1/2 shaft splines today for you.

The diff I am using is a S14diff with 3x2 halfshafts so I am not sure it will be the same.

[dead32]

gl with this mate.. just make sure you get the preload right

[Cubes]

Let me guess? blocks of wood and a hammer?

sure will count the 1/2 shaft splines today for you.

The diff I am using is a S14diff with 3x2 halfshafts so I am not sure it will be the same.

It will be fine. The 3x2 halfshafts are interchangeable with the 1x5 halfshafts.

yes Blocks of wood and a mini sledge hammer.

[CEF11E]

the half shafts have 29 splines.

anyone have any experience with preload and diffs? can you give me any tips?

Thanks!

[salad]

Thanks Salad,

yep. I have pulled the centre apart and found there to be 2 preload washers

1 on the onderside of the viscous centre and one on the other sode of the spider gears carrier ( opposite ends of the housing)

I found that when I put the second shim in the whole assembly would not screw down completly leaving a 1mm gap between the 2 halfs of the pumpkin.

Did you find the same thing?

I dont remember one being on the other side of the spider gears carrier, although it may have been stuck to the housing?

There was a gap when I slid the 2 parts back together, but once the screws were tightened the gaps were pretty much gone.

[Cubes]

hrmm..

My Q45 half shafts that bolt up to the GTR axles run a 30spline.

The GTR axles run a 31spline in to the hub.

[Cubes]

I dont remember one being on the other side of the spider gears carrier, although it may have been stuck to the housing?

There was a gap when I slid the 2 parts back together, but once the screws were tightened the gaps were pretty much gone.

Hows the VLSD you shimmed holding up?

[salad]

I was actually just trying to sell my old VLSD centre so I just shimmed it to sell it. Sold it to a guy on NS.com and havn't heard back from him since, so I assume it's still goin. I can get onto him and ask him how it's goin if you want?

I shimmed it the same way as a couple of my mates did aswell, and theirs are still going after over a year of track and daily driving.

Edited January 27, 2007 by salad

[Cubes]

So when you say you put in a 1.49mm + the stock 0.8mm you had a total of 3 shims?

Or did you remove one of the 0.8mm shims at the opposite end of the spider gears?

I'm assuming you had a total of 3 shims.

[salad]

Yeah, left the stock ones and added one.

I didn't realise there was one on top of the spider gears though. Guess it makes sense that there would be one there. Must've been stuck to the housing so I didn't see it.

I was mainly going off the guide I posted earlier. It said if I wanted it very solid, put 2 extra stock shims in, so extra 1.6mm, I put in an extra 1.49mm, close enough.

Edited January 27, 2007 by salad

[CEF11E]

I am still deciding what level of shimming to use.

I bought 2 1.01 shims and think I will use one of those either side. I am not after a locked diff and the centre will not screw together with 3 shims in it there is a 1mm gap.

I can not turn the centre at all by hand using the 1/2 shafts with the 2 1.1mm shims in so i presume it will be fairly tight.

[Cubes]

I'll be watching this thread carefully.

[jnr32r]

I put in a 1.2mm + the std 0.8mm shim in mine and i hated for the first few weeks, as it felt like i was driving a train when turning corners with a constant "clanking" sound.

A couple of months later sound and locked feeling has worn off and still not open wheeling... Plus the car feels so much more predictable... it reminds me of when i first got the car with 64K Km on it....

Mistake i made when assembling it together was not putting in shafts before tightening crown, as splines did not line up and hence shafts would not go in all the way...