320i lsd conversion

[felix_666]

I'm pretty sure you still need spacers due to difference in diff width, like i mentioned it will visually look right but there is a reason why the cv's are able to slide around an inch or so.

[peteinjp]

here is a pic of the 76 flanges side by side with the 320's. Just get the snap ring grooves machined off and your good to go. This is the easiest and cheapest way to go- uses your axles and no spacers.

[1669]

here is a pic of the 76 flanges side by side with the 320's. Just get the snap ring grooves machined off and your good to go. This is the easiest and cheapest way to go- uses your axles and no spacers.

who has machined 76 flanges they want to sell?

[peteinjp]

Any machine shop can do it for cheap- you may not even need to machine them. try getting in touch with varco, torres, 2002ad etc etc and see if you can fine some.

[OldSkool]

So if you're starting with a '73 2002 that already has the 5-speed conversion done...

... what do you need to do to fit an LSD from a '79 320is?

And what ratio was the diff in a '79 320is? Is there an easy reference somewhere?

[finkbuilt]

So, is there a way to tell if your 76 flanges are really of the "pop out" variety? I have a 76 diff, and I am banging on these flanges pretty hard, but they aren't coming out. I really dont want to bend them.

I dont see any bolt on the exterior center of the flange. Are some 76 flanges pop-outs and others not? I've got my LSD sitting there on the bench and I am drooling, and there is a big empty space between my rear axles where the 76 diff used to be.

-s

here is a pic of the 76 flanges side by side with the 320's. Just get the snap ring grooves machined off and your good to go. This is the easiest and cheapest way to go- uses your axles and no spacers.

[peteinjp]

The 76's are held in with a circlip- you have to pull the rear cover. The machining involved is just to put the groove in for the spring clip used on the 320 set-up and I also beveled the (inboard) end like the 320 unit so it would slide in easier.

[Bill_Riblett]

And what ratio was the diff in a '79 320is? Is there an easy reference somewhere?

77-79 320 diffs were 3.64 ratio. 80-83 320 diffs were 3.9 ratio.

There is a FAQ on this website about diffs:

http://www.bmw2002faq.com/content/view/17/32/

[finkbuilt]

Oh, Thanks.

So.... Of course, the answer to the next question is "of course you should machine the detent into the flanges". But what would happen if i just slid the 76ers in there and bolted it up?

I mean, they can't really go anywhere, right?

has anyone just skipped the machining, and how's that working out for you?

The 76's are held in with a circlip- you have to pull the rear cover. The machining involved is just to put the groove in for the spring clip used on the 320 set-up and I also beveled the (inboard) end like the 320 unit so it would slide in easier.

[TobyB]

Depending on how tight they are, they might manage

to slide out just enough to let the seal ride off its sealing

surface, causing leaks.

But I bet they wouldn't.

t

[peteinjp]

Maybe- maybe you could put them into the 320 unit with the circlips used in the 76. Other wise I'd get the grooves cut. It was only about 20 bucks and it took a day or so.

[finkbuilt]

Maybe- maybe you could put them into the 320 unit with the circlips used in the 76. Other wise I'd get the grooves cut. It was only about 20 bucks and it took a day or so.

You may be able to try that with an open diff, but not with an LSD. (the output shaft ends are covered by the clutch pack housing - or whatever you call it).

[finkbuilt]

Well, I volunteer to be the Guinea Pig. I'm not worried that anything catastrophic is going to happen.

I put the 76 parts on - finned rear cover, and output flanges - and installed it. the overall width flange to flange face came out 1/16th narrower than the 76 open diff originally was. I went with it. No drilling, no spacers, original axles.

Seems to work fine (love the traction!). I will keep an eye on it, and if I hear any strange sounds, or leaking in the coming days. I will pop them out and put the grooves in.

I had the 76 diff already, I put it in to get the 3.9:1 to compliment my 5 speed (couldnt afford an LSD at the time). If I did not already have it, I probably would have gone with the drilled flange and spacer approach.

Here is how the LSD looks wearing 76 parts:

Depending on how tight they are, they might manage

to slide out just enough to let the seal ride off its sealing

surface, causing leaks.

But I bet they wouldn't.

t