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E21 Lsd In A 2002 - Axle Woes

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Hi everyone, I know that this has been discussed by many but I'm having some issues with what I thought was common knowledge posted on the internet.

 

I've been trying to build a set of axles for a late E21 LSD I've picked up (3.91:1, 10mm threaded holes on the flanges). I've seen quite a few ways to do this, from getting axle flanges redrilled to 8mm and using 5mm or 1/4" spacers, to swapping flanges, to drilling CVs out to 10mm.

 

The route I'm trying to take is one that I've seen posted more than once: Take a stock 2002 CV, a stock 2002 axle shaft, and a '79-only E21 CV, and build an axle which requires no drilling, spacers, or tapping. However, upon building an axle with this combination, I'm left with an axle which is roughly 1/8" shorter than a stock 2002 axle - I figure this number by taking the offset from the flange face of the midpoint of each CV. The CVs from the '79 E21 appear to be moved inward (toward the axle shaft) by about .150" when compared to the 2002 CV.

 

Now because the differential is about 10mm more narrow on the E21 compared to the 2002, this is obviously not ideal.

 

My understanding of this combination, and the reason I wanted to build them this way, is that the '79 E21 CVs are thicker by the correct amount to make up the distance that would normally be taken up by a spacer. But from what I've measured, this is not the case, and they are actually effectively shorter than a standard 2002 CV.

 

There are two possibilities that I can think of - the inner CVs I have are not actually from an '79 E21. I can't really verify this as I found them in a crate of misc. 2002 and E21 halfshafts, but they are stamped with "04/79" and bolt up to the differential I have, so I assume they are correct, but being that I've never seen any pictures or dimensions of these one-year-only CVs I can't be 100% sure. The other, more likely possibility, is that I don't like the data that I've collected and can't accept that something I read on the internet is untrue :P

 

Has anybody else struggled with this? I thought this would be a straightforward process but as I look at more axles and measure more dimensions, it seems like BMW changed something about the axles approximately every 5 minutes. I'll have some pictures up later today of some problem areas I'm having.

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'79 E21 CV:

 

0HiN4Ut.jpg

 

OObeHRT.jpg

 

d6exr9s.jpg

 

'02 CV:

 

hULfCIa.jpg

 

5mre44C.jpg

 

Now I've measured the E21 axle shaft vs. the 2002 axle shaft, and the overall dimension is different between them (at 15.25" vs 15.625", respectively) but the length between the splined sections is the same, at 12.75" - best as I can tell, this is the only dimension that matters as when the CVs are seated all the way (with the cupped washers, I will add) this is the limiting factor.

 

So now my question is, should I be using the supposedly longer '80-'83 shafts with '79 inner CVs and 2002 outer CVs??

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Yes, I'm sorry for failing to clarify. I've always used '80 and newer E21 shafts. I actually didn't realize that early / late E21 shafts were different.

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well, either your pics are mislabeled or you are confused as to which is which.  the pics labeled 320 cv's are actually 2002 cv's.  here is pic of axles with 320 at one end (inner) and 2002 at the other (outer)...

DSCN5653.jpg

Edited by mlytle

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to save folks from having to down load that file and make it show up in a search, here is the text...

<i am making no claim that any of the below is accurate, i am just posting it>

-----------------------------------------

I have done the same measurements and agree with the following: 
 
Ok, I did post about a month ago on this, but I've since had completely apart 2002, early 320i and late 320i CV joints and halfshafts(axles)(to 1982). I measured everything in detail, and here's the final skinny on the whole situation: 
2002 CV joints and halfshafts (except I don't know about 02s prior to 1970) and early 320i CV joints and halfshafts are EXACTLY the same thing, up until 1978. Period, end of story. There might be a couple of thou. differenced here or there, but it's negligible, and might just be due to the supplier BMW used. 
 
In 1979, and only 1979, the CV joints in 320i's changed from 8mm bolts to 10mm bolts. Otherwise, the CV joints and halfshafts have the exactly the same style CV joints and the overall length from outer face to outer face of CV joints. 
 
In 1980, the halfshafts changed to a longer version, but still using exactly the same splined shafts ends. They are longer by 9/16" overall. Also in 1980, the CV joints were changed to a 'thinner' style. They have a 3mm shorter outer bearing race surface as compared to the earlier ones, but the bearing cage and inner bearing race are the same. The earlier 320i (and 02) ones are thicker as they have a sort of built in 'spacer' in effect due to the design of the end cap on them. 
 
And early 320i diffs. to 1978 all have 8mm bolts, the same as 02s. 1979 and on diffs. use 10mm bolts. 
 
So, as an end result, you need spacers in any event, but the thickness varies. The thickness allows for the CV joint bearings to ride in the center of the joints, as they were designed to. DO NOT try to get away without using them, however tempting it may look. The bearing cages move back and forth and project beyond the limit of travel of the bearings against the races. As a result, you would chance the cages punching out the end caps on the CV joints. 
 
If you have an early 320i diff. (open or LSD) you need 02 outer CV joints and 02 or early 320i axles. You can use 02 or early 320i inner CV joints. You will need a 1/4" spacer between the inner CV joint and diff. You can use the early 02 CV joint bolts that used a nut on one side, as they'll be longer. I'd suggest getting new ones though. 
 
If you have a later 320i diff., you have two options. You can use 02 outer CV joints and 02 or early 320i axles and 1979 only 320 CV joints on the inboard end. You will need the same 1/4" spacers with this setup, but will need longer 10mm bolts. Alternatively, you can use 02 CV joints on the outboard end, later 320i axles and later 320i CV joints on the inboard sides. With this setup, you will need 3/16" spacers and longer 10mm bolts. 
 
Whew! I hope that's perfectly clear. The mistake I made earlier was that I was in a mad dash in and out of a salvage yard, and accidentally included the thickness of the diff. flange when I mic'd. the 79 320i CV joint. 
 
For those trudging around salvage yards, keep in mind that the outer CV joints normally wear out sooner than the inners, because of the constant up and down pounding from the wheel movement while driving. So don't just buy one side expecting to two good CV joints. Also, it's very labor intensive for salvage yards to remove the CV joints. You'll get a much better deal at a yard that will let you remove them yourself. That way, you'll also get to inspect them before getting them home. I got a package deal at one salvage yard by buying the complete subframe including diff., CV joints, axles, complete brakes (good for 02 upgrade) and useless stuff like trailing arms. BUT, it had an LSD that I knew about and they didn't!! 
 
Various 02 aftermarket places have the 1/4" spacers and longer bolts. One such place though is flogging .375" (3/8") thick spacers. I have no idea how these would work. 
 
Hope this helps. 
 
Gil 
72 Tii
-----------------------------------------------
<again, NMNA>
Edited by mlytle

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You're supposed to use the E21 inner joints AND shafts along with 2002 outer joints. I've done this many times and it works perfectly.

 

This, with 10mm E21 shafts.  

 

t

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to save folks from having to down load that file and make it show up in a search, here is the text...

Click on it and select "open".  No download necessary.

Edited by jimk

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Click on it and say "open".  No download necessary.

depends on what browser you are using, and what security settings you have....not always the case that it just "opens"...

 

plus putting the text in the thread makes it show up in a search for the next person.. :)

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Slight thread hijack...

 

I have a 3.64 LSD from (presumably) a 79 or earlier 320 that I have not yet tried to install...will my 2002 axle shafts fit--both lengthwise and bolt size?   How can I tell?

 

TIA

mike

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depends on what browser you are using, and what security settings you have....not always the case that it just "opens"...

 

plus putting the text in the thread makes it show up in a search for the next person.. :)

Sorry you went thru all that trouble, next time I'll keep the info to myself.

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Sorry you went thru all that trouble, next time I'll keep the info to myself.

did santa leave you a piece of coal?   :)

it was good you had the info.  i was just trying to help others find it...

Edited by mlytle

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Slight thread hijack...

 

I have a 3.64 LSD from (presumably) a 79 or earlier 320 that I have not yet tried to install...will my 2002 axle shafts fit--both lengthwise and bolt size?   How can I tell?

 

TIA

mike

from the jeff ireland differentials guide in the articles section of the faq..

"Early e21 ('77 and '78) 320i's have four bolts holding the side covers, but the output flanges are held in by a C-clip inside the diff. These diffs usually have 8mm bolts for the CV joints but some use the later 10mm bolts. These early diffs are the same width as the 2002 diff so no spacers are necessary if you are putting one in a 2002."

 

it appears if you have four bolt side covers the diff should be same width as a 2002 diff.

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JimK, Mlytle, and everyone,

 

ALL of this info helps. I have been in halfshaft hell for a week. I am refurbing my rear suspension and upgrading to an E21 lsd in the process. Turns out I have just about everything- 2002 CVs on 2002 shafts, 320i/2002 CVs on some shaft, some of the presumably early 320i shafts with the thin ends, and several damaged 2002 CVs. Some shafts have the cup washer, some do not. To further complicate it, i have 2 lsd 3.90 diffs, one with 10mm bolt flanges, one with 8mm.

 

So I have 2 questions:

1. Is the 10mm bolt E21 diff any better or stronger than the 8mm? I will be running twin webbers on a mild engine, not a turbo or anything too crazy.

 

2. What is the ideal length, end to end, for a fully assembled halfshaft with two CVs, for a 2002 with a E21 LSD diff? This seems to be the bottom line question, so I can figure out what spacers, if any, I need to use regrdless of what axle/CV combo I put together, and which diff I use.

 

Thanks, and merry Christmas!!


JimK, Mlytle, and everyone,

 

ALL of this info helps. I have been in halfshaft hell for a week. I am refurbing my rear suspension and upgrading to an E21 lsd in the process. Turns out I have just about everything- 2002 CVs on 2002 shafts, 320i/2002 CVs on some shaft, some of the presumably early 320i shafts with the thin ends, and several damaged 2002 CVs. Some shafts have the cup washer, some do not. To further complicate it, i have 2 lsd 3.90 diffs, one with 10mm bolt flanges, one with 8mm.

 

So I have 2 questions:

1. Is the 10mm bolt E21 diff any better or stronger than the 8mm? I will be running twin webbers on a mild engine, not a turbo or anything too crazy.

 

2. What is the ideal length, end to end, for a fully assembled halfshaft with two CVs, for a 2002 with a E21 LSD diff? This seems to be the bottom line question, so I can figure out what spacers, if any, I need to use regrdless of what axle/CV combo I put together, and which diff I use.

 

Thanks, and merry Christmas!!

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