02-05 motor question
Three Wheelin'
Joined: May 2010
Posts: 1,851
Likes: 9
From: Nor Cal
All normally aspirated 996/7 911's up until 2008 have an IMS bearing and are therefore susceptible to IMS bearing failure.
All 911 including and after 2009 do not have an IMS bearing as they moved a totally new DFI engine design.
Turbo engines are based on a completely different design, and therefore do not suffer IMS bearing failure.
All 911 including and after 2009 do not have an IMS bearing as they moved a totally new DFI engine design.
Turbo engines are based on a completely different design, and therefore do not suffer IMS bearing failure.
Last edited by logray; Oct 10, 2011 at 11:20 PM.
Race Director
Joined: Sep 2006
Posts: 19,035
Likes: 269
From: Bentonville, AR
All 2002 to 2005 and even up to 2008 engines can suffer from an RMS leak. In fact the GT2/GT3 engine can be more prone to RMS leaks than the other engines since Porsche used a lower friction seal which may not seal quite as well. It doesn't help either that many of these cars do not get used regularly and the seal dries out, shrinks, and leaks. A new seal is installed and the car sits unused for long periods and leaks again. (Another problem I read about is the seal is different and some few times the new seal was installed the wrong way 'round which had the new seal leaking again in no time.)
Anyhow, the last couple of years before the switchover -- from 2006 up to and including 2008 -- may have less risk but we won't know until these cars start to get older and accumulate more miles.
Still, many cars from every model year do not leak or once fixed do not leak again. And many many cars do *not* suffer an IMS failure.
Sincerely,
Macster.
Drifting
Joined: Apr 2006
Posts: 2,032
Likes: 29
From: Out West
Turbo and GT3 use a totally different motor known as the GT1. It's essentially the last air cooled design with a water cooled top end. I believe it was the basis for the GT1 racer and is very understressed for use in the GT3 and the Turbo. The GT1 motor uses a true dry sump and is unaffected by high G cornering and braking forces as far as oil starvation.
The M96 motor used in the first gen Boxster and water cooled n/a Carreras except the GT3 was the first Porsche motor to use lokasil cylinders which in some ways is looking inferior to nikasil liners used previously. The early motor castings were plagued with porosity, many of which were sleeved only to have the sleeves slip causing catastrophic engine failure. Many heads were cracking as well for no apparent reason other than a design flaw and generally in the same area and only on one bank causing coolant and oil intermix resulting in motor failure. Intermediate shafts on early motors were known to break. A rare occurance but happening often enough that Porsche redesigned the shafts and supporting bearings several times. The latest factory design ran up to '05 in the 997 then was changed for '06 where the problem, I believe is pretty much nonexistant.
The M96 motor used in the first gen Boxster and water cooled n/a Carreras except the GT3 was the first Porsche motor to use lokasil cylinders which in some ways is looking inferior to nikasil liners used previously. The early motor castings were plagued with porosity, many of which were sleeved only to have the sleeves slip causing catastrophic engine failure. Many heads were cracking as well for no apparent reason other than a design flaw and generally in the same area and only on one bank causing coolant and oil intermix resulting in motor failure. Intermediate shafts on early motors were known to break. A rare occurance but happening often enough that Porsche redesigned the shafts and supporting bearings several times. The latest factory design ran up to '05 in the 997 then was changed for '06 where the problem, I believe is pretty much nonexistant.
Three Wheelin'
Joined: May 2010
Posts: 1,851
Likes: 9
From: Nor Cal
"Just to add myself to the statistics, my 2005 Boxster had 27,000 miles when the IMS failed, all service done by the dealership, and never been abused etc. In fact, most people say I drive like a grandmother, haha. My failure occured while coasting down a long downgrade."
http://www.renntech.org/forums/topic...ost__p__210347
Honestly, a separate forum for IMS posts, perhaps a sub forum, is a GREAT idea.
http://www.renntech.org/forums/topic...ost__p__210347
Honestly, a separate forum for IMS posts, perhaps a sub forum, is a GREAT idea.
Parts Specialist
Rennlist Member
Rennlist Member
Joined: Aug 2008
Posts: 16,326
Likes: 30
while there are a few that do...I dont have a complete list of those handy
