IMS settlement follow up - 986 Forum - The Community for Porsche Boxster & Cayman Owners

kashmir · 09-23-2013, 01:08 PM

Quote:

Originally Posted by Trey T

Prior to 1996 when the Boxster came out, what type of bearings did they use for the IMS?

On air cooled 911 it is a lapped bearing with an insert to support the rear journal.

Trey T · 09-23-2013, 03:37 PM

Do you know why they change it to roller bearing? is it because of assembly issue?

Quote:

Originally Posted by kashmir

On air cooled 911 it is a lapped bearing with an insert to support the rear journal.

kashmir · 09-23-2013, 04:17 PM

Quote:

Originally Posted by Trey T

Do you know why they change it to roller bearing? is it because of assembly issue?

The other side of the IMS shaft has the lapped bearing and the 8mm key that drives the oil pump, so there is plenty of lubrication on that side of the engine. It does cost money to cast into the block the oil passages. Plus it is easy to the drive cage bearing into the block on the flywheel side so you have speed of assembly. The original duel row bearing is only use by Porsche, to save more cost after they thought it was safe to build cars that way, they started to use an over the counter single row bearing that is also used in a GM alternator I believe and that is when things started to go "Tic Tic Boom!!''

thom4782 · 09-23-2013, 04:45 PM

The total failure rates - dual 1% and single 8% - were provided during the discovery process of the IMS class action lawsuit. The 7% is the incremental difference between to two.

Trey T · 09-24-2013, 09:28 AM

I see. Thanks.

Quote:

Originally Posted by kashmir

The other side of the IMS shaft has the lapped bearing and the 8mm key that drives the oil pump, so there is plenty of lubrication on that side of the engine. It does cost money to cast into the block the oil passages. Plus it is easy to the drive cage bearing into the block on the flywheel side so you have speed of assembly. The original duel row bearing is only use by Porsche, to save more cost after they thought it was safe to build cars that way, they started to use an over the counter single row bearing that is also used in a GM alternator I believe and that is when things started to go "Tic Tic Boom!!''