05-03-2012, 10:16 AM
Join Date: Jan 2009
Location: Atlanta, GA
My Ride: 2002 330i Orient Blu
I've already gone down this road and luckily came across a 4-clutch LSD from turner for a great price, but here's my two cents regarding retrofitting the older unit as you are attempting. Instead of doing all the machining and spacer for the top hat, which by the way will require you to make a spacer for the inside of the unit to keep the clutch pack stack preloaded as original (you could add additional clutch stacks if you measure it out right); just machine a spacer for the ring gear so that it lines up with the e46 pinion.
Looking at your photo below; measure the offset between the open and LSD unit where the ring gear sits and machine a spacer of that thickness. Then you can mess with the order of the clutch pack stack inside the LSD to center the spider gears so that they match the open unit or do some machining to perform the offset and add additional clutches. I'm pretty sure the measurement you come up with for the ring gear spacer will also be how much the spider gears need to move.
But not to be a bummer, the wangan dude is right when he says you have to do a lot of grinding in the diff case to be able to make this unit fit. And with all that grinding, you'd better make sure not a single piece of trash makes to to the pinion gear bearings otherwise goodbye diff. When I got the turner diff I still had to remove material inside the case
to make it work, but it was a very small amount and I used a file and packed a ton a grease around the pinion to keep shavings out of the front of the case.
Anyhow, goodluck buddy. Pm me with any questions; and if you ever sell those schrick cams I expect to be the first one you contact.
Originally Posted by aggieE46
So, here's where we are:
As you can see from the picture, the units themselves seem to be the same height. I haven't measured, but they're pretty darn close. So to add to my excellent illustrations, here's what I'm supposed to do next. The LSD must be modified so that the ring gear is in the same position as it is on the open differential. As you can see, it's too long. I will need to have the bearing seat and shoulder milled down so that it matches. That's the next step.
I'll get ahead of myself and say that after that, the unit itself will be too short. I will then have to have a spacer made to space the bolt-on cover out towards the driver's side. That will make the LSD unit the exact length of the open unit and put the ring gear in the same position as it is on the open unit.
Enjoy the update!
After a fresh wash and wax.....
Too many mods to list, but the best one is my 3.23 LSD from Turner mated to an M3 box with UUC dssr and SSK ;)