Which "Center Support Bearing" for "early model" E30 w/ M54 swap? (two options)

[Dave325esE30S54]

Which "Center Support Bearing" for "early model" E30 w/ M54 swap? (two options)

Hey everyone, I am trying to figure out which CSB to use for my swap into my 10/86 325es that is getting an M54B30 w/ ZHP 6spd.

The E30 changed its DriveShaft in late 87, and the CSB along with it, so there are two CSB options, an early and a late model, but I don't know if the CSB corresponds to the early/late BODY or the early/late DS. I am half guessing the body/mount-point did not change, and it corresponds to the DS change, so that would mean I want the late model CSB to work with the E36 DS, but that is just a guess.

I already figured out the front section from a Z4 M/S54 6spd Manual and the rear section from an E36 M3 Automatic (or a number of E36 Automatics), but I am struggling to find clarity on which E30 CSB to use. If I was putting this into an 88+, this would be no problem, because I would use a "late model" CSB, but everywhere I look everyone just says "use an E30 CSB", not which combo of early/late, etc...

Help/Guidance with this would be greatly appreciated!

[mtech325]

Based on this thread, you would need the early CSB to match with your chassis:

https://www.r3vlimited.com/board/forum/e30-technical-forums/24v-engine-swaps/m50-52-s50-52/327903-driveshaft-center-bearing-design

[ForcedFirebird]

The CSB has to match chassis as identified in the previous post BUT, when using an e36 drive shaft, you have to mount the bearing in reverse - not sure how you would do that with an early model since the CSB is offset mount in comparison to a late (and E36) with a centered mount.

Also, the 6 speed is a fair bit longer than the 5 speeds, so your shift selector rod, and support are going to have to be shortened, and the selector will need to be curved to go over the large Giubo. I have never used the Euro E36 s50b32 selector/support as we have fabrication equipment at work, but it is said to fit.

The simplest way to sort the drive shaft is to have a competent machinists and fabricator to cut the 3 finger yoke off a big Giubo drive shaft, and cut the stock e30 shaft. Then lathe turn a step in the yoke so it can press in the shaft, and be welded back in taking care to orient the yoke same as it was when removed. Many e30 drive shafts will grow narrower as it approaches the transmission, so a 318i shaft is guaranteed to have the thick part long enough for the modification (m42 and m10 shafts are much longer). A local car we built at work has been running this mod in his s54/6speed that is now supercharged for about a year with zero issues.

You have the mix and match reversed for the front and rear shafts. All e30 and e36 rear halves are the same length, the front is what is shorter/longer to compensate the trans length.