Jim996cab

Happy Sunday,

Changed the oil for the first time since buying the 2000 996 cab 6-speed 2 weeks ago (low 27,000 miles.) No glitter in the oil, and none in the oil filter pleats that I cut open.

When I first bought it, I thought for certain I would immediately have the IMSB upgraded. However, the more reading I do, I’m considering not doing it till new clutch or whatever. It seems the odds of bearing failure or pretty low, especially on the dual-row models.

A fellow Rennlister tells me that mine is the dual-row version (built 11-99).

Having said that, I’m not finding search answers for my question: can someone tell me when the dual-row bearings were used?

Thank you.

-Jim

wyovino

I haven't seen any firm answers on that but I know that my build date 01/00 has a double-row. Even some 2001's have double row bearings.

su8pack1

My 2000 has a build date of 11/4/99 and never an IMSB problem at 93,000 miles. I have most, but not all paperwork going back to new and no mention of it being replaced.

Barn996

I believe that MY1998,1999,2000 have the double row bearing.

Splitting Atoms

The experts that have posted on this site have stated that the MY1999 are all dual row (assuming they have their original engines). The MY2000 and 2001 are a mix. It appears that many of the earlier MY2000 are dual row. If I had a 2000 or 2001, I would look at the IMS cover bolt at the first opportunity (clutch replacement, RMS leak, etc) to see what I had.

dporto

There's a good chance it's a dual row bearing. That being said, there are no hard and fast rules. My '99 has a replacement/swapped engine in it from 2000 (M96-04) and it is indeed a dual row... No longer though because I installed "The Solution" (dual row version) a little over a year ago.

808Bill

If your oil was not changed annually, there could be some etching caused by stale oil. Do you have all the service history? I'd install the Solution and never give it another thought...There are many other "modes of failure" you can then focus on.

sparks259

peterp

My 2000 996 (production date 6/1/2000) has dual row IMS.

sparks259

wyo

my 2000 C2 has the duel row - I think that not having a duel row bearing in an MK1 3.4 car is rare - all of the 1999, 2000 and 2001 were not included in the class action based on Porsches records that they used the duel row in all of these cars, but as many of you know there are examples of MK1 cars being torn down and revealing that they have a single row bearing.
It has also been said that they changed to the single in mid year of the 2001 model but who really knows

Stephen Tinker

I guess it comes down to when the engine was built, not when the chassis / power train was assembled (ie build date), as to assess if you have a double or single row bearing. Manufacturers usually have crate loads of built motors sitting on palettes waiting to be co-joined to their chassis.
My old Boxster S was assembled in January 2001 but still had a double row bearing when I replaced it back in 2010, so the engine was assembled quite some time before final installation into the chassis.

NuttyProfessor

According to PCA, Jake Raby, and LN, the dual row bearing was phased out in model year 2000. If you watch any of the PCA videos with Jake, he makes a very valid point that although the dual row bearing is the most durable of the three designs, it produces twice the wear material that will contaminate the engine when it goes bad. Also, he also mentions that you can't buy any car, whether it be a 1999 or 2000 car and assume it's going to have the original dual row bearing. It's highly likely one of the owners swapped out the bearing giving you a false sense of security.

NuttyProfessor

You make an excellent point! The engine could have been assembled at a much earlier dated than the entire car was manufactured. That's probably why a small hand full of 2001 cars have shown to have the dual row bearing.

peterp

I'm not at all sure this is accurate (my own car seems to be a violation of what's stated), but according to this post -> https://rennlist.com/forums/997-foru...ml#post7944762

996 had Double Row for engine numbers up to 661 14164
996 have Single Row from engine number 661 14165 onward


Boxster: Double Row: up to 651 12851 (M96.22)
Boxster: Single Row: from 651 12852 onward (M96.22)
Boxster: Double Row: up to 671 11237 (M96.21)
Boxster: Single Row: from 671 11238 onward (M96.21)