LSDs lets talk

[BarryG]

the sideloader case and cover



and the guts of a LSD



My problem is the bottom 2 disks, if i put them in i can't close the cover tight. I'm told you can change or replace some parts to get more lockup.

If you know more than me and I'm sure you do feel free to chime in.

 

[srennoc]

LSD Carrier

Barry,
Do you have a digital caliper? If not, get one
You need to measure your housing, cover, inner & outer discs, belleville springs & document it. The stack needs to be built within .1mm to .4mm clearance to work correctly. Any thing larger will slip & burn the clutches up.
It looks like you have purchased two new 2.0MM inner discs. The early carrier will only hold two inner & two outer discs on a side loader. Use to replace your old. No room to machine housing to hold more like later 188mm units. Did your diff have a 4MM spacer in it? if so, you can remove it to add one additional inner & outer discs that measure 4MM combined.
Outer discs are available from Porsche in various sizes to shim up the preload of housing.. BMW does not supply these anymore. I have all the part #s if needed. Also bimmerdiffs.com sells the needed parts.. Replace your 8MM carrier bolts with new 12.9 pieces.
The process is written up in the blue shop binders..25% LSD not 40%
Call if you need help

T

 

[BarryG]

I talked to Terry today and we discovered my diff is a stock 40% lockup from a early 70 e3.
Here's the stamp on the housing.



So there's a 25% 40% & a 75% stock lockup.

more to come.

Barry

 

[BarryG]

Come to find out the 2.0mm inner disks that are in the first pic were extra pieces that were not in my diff. They were throwen into the box of parts after it was taken apart. go figure
It all fits correctly, just need to get new the parts.

B

 

[DerSchwede]

Yes, 40% LSD up til bieginning of '71, then they switched to 25%. You can easily tell from the type of housing which part you have - even if the stampings are gone; you open the early part where the cromw wheel is fitted, the later style has the cover on the other side.

Oh, most 40% LSD has special molybdene covered inner discs. But there are two different housings depending on if you have the early type with or without those discs and they are NOT interchangable!!!

Cheers
A

 

[Peter Coomaraswamy]

Barry, I'm sure this is a dumb question but what do the percentages mean regarding "Lock-up" 40%, 75% etc,?

Thanks

 

[BarryG]

got this from the cs registry.

//www.e9-driven.com/Public/Library/BMW-E9-Manual/pages/en/33145930.html

Peter, I am very new to the lsd diff... I believe that a 25% takes more torque/ throttle/power and a 75% less.

look at the V where my finger is pointed , see how the belvel gear rod rides up on the v.. That puts pressure outward on the clutch which creates lockup.

I could be wrong , again I'm just learning.

bimmerworld has these. 188mm

http://store.bimmerworld.com/motorsport-limited-slip-clutches-p584.aspx

Check out this site.
http://www.bimmerdiffs.com/

 

[Peter Coomaraswamy]

Thanks Barry, When I met with sfdon he checked out my coupe and said the rear was "open" so the lsd is the very last thing on my list....I think