Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > BMW > 3 Series
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools Search this Thread
Old 02-21-2002, 06:15 AM   #1
hayden747
AF Newbie
 
Join Date: Feb 2002
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Question 320 e21 DIFF problem, suggestions ?

Hi everyone, the problem I'm having started as soon as I upgraded the engine in my 1979 BMW E21 320. After installing a larger model engine, and programmable EFI I had problems with the diff. On the very first day I got the car going the diff LITERALLY exploded ( in second gear at full power) , the actual structure of the crownwheel & spider gear carrier sheared in half, leaving bolts, oil, and bits of broken metal all over the road.
I discovered this was due to 2 design faults, the main one being the way that the roll-pin which retains the main pin the spider gears sit on is installed. The hole for it is drilled parallel to the line of shear force ( creating a stress - riser ) rather than perpendicular to the line of shear force ( which minimises weakness, as in Nissan diffs )
I was thinking of maybe installing a LSD from a series 5 RX7, but this would involve a lot of modification of driveshafts and mounting points.
Any sensible suggestions on how to fix this problem would be appreciated. I have already got another second hand diff and am being careful not to use too much power. I had thought of grinding away the material from the outer side of the roll pin hole, to make a channel in the material, then getting that channel filled up by TIG welding, but I have been told that because the carrier is made of cast material it makes welding the material successfully very difficult.
Are there any other bmw diffs of diff parts that might be easy to fit without too much modification ?
Thanks.
hayden747 is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Bookmarks
Go Back   Automotive Forums .com Car Chat > BMW > 3 Series

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 12:55 PM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts