07-25-2013, 11:02 PM
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#1
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Registered User
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
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very very good info in this thread!!
Thank you Husker for a thorough explanation
What many do not discuss with the 05.5 and up M97 engines? The bearing is MUCH MUCH bigger than the M96 bearings (I mean diameter bigger) which means it turns at a lower rpm than the M96 bearing (it's already turning half of crankshaft speed) + it has more ball bearings!!
I haven't seen a failure of this larger M97 bearing (yet) and I have had 8-10 of them come through the shop (engines) and 15-20 987/Cayman customers.
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07-26-2013, 07:35 AM
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#2
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Join Date: Nov 2004
Location: New Jersey
Posts: 8,709
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Quote:
Originally Posted by pothole
Sorry, what? The 2.9 engine isn't DFI, but all the 9A1-based engines (so all 987.2 and 997.s wet sump engines) have no IMS, have closed deck bores and revised cooling.
What exactly is it you think the 'mid-engine' models are missing?
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must have been off my meds. Got my Caymans wrong. 987.1 Caymans did not get m97 updates found on the m97 Carreras.
Quote:
Originally Posted by Brad Roberts
I haven't seen a failure of this larger M97 bearing (yet) and I have had 8-10 of them come through the shop (engines) and 15-20 987/Cayman customers.
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But we also haven't yet seen a huge number of m97 Cayman and Carrera with really high mileage either. One of the reasons Porsche is near the top of the reliability rankings is due to low mileage, only the Cayenne sees consistent daily driving among its owners. As a class, Cayman, Carrera, Boxsters take over a decade to see high mileage...precisely when they start becoming affordable to most with more limited budgets. Once these new bearings start going well north of 100K miles and they start to become really contaminated/dry out/under-perform and the then current owner opts not to spend the considerable amount of money to crack open the engine to swap out the old m97 IMSB for fresh one, what's going to become of these engines? I really can't think of any reason that these bearings are going to sit still in the engine forever. Fahrvergnügen?
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Last edited by Perfectlap; 07-26-2013 at 07:42 AM.
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07-26-2013, 08:25 AM
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#3
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Registered User
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
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Perfect?
I have multiple 987 customers with over 100k on them. Most are in the 80k range right now.
This is SoCal. We driver our cars  We don't own a *winter* car or have *winter* tires
Now that I think back, I have at least 2 in the 115k range.
My Texas shop owners have all reported 987's well into the 90k+ range.
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Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
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07-26-2013, 11:52 AM
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#4
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Registered User
Join Date: Nov 2004
Location: New Jersey
Posts: 8,709
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Quote:
Originally Posted by Brad Roberts
Now that I think back, I have at least 2 in the 115k range.
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That's sort of my point. You're running a shop and even then you only see a handful north of 100K. It's too early to give the m97 IMSB the all clear since, and this is the important part, most are still in their reasonable life expectancy period.
Firgure the m96 single row that fails, under suboptimal care/use, was only good for ~50-70K or less, I would presume that the m97 bearing would be good for double at most? Probably less since once the bearing is contaminated, neglected for too long, the drop-off comes quickly.
The other issues seems to be, as you point out, your cars are actively driven by its owners. Will an m97 IMSB that was driven meekly, short shifted, etc. and sat for long periods (typical Porsche usage), fare as well once the bearing is long past the 'sell by date' -- and ALL bearings have one. In other words, m97 IMSB's seem to be doing a good job during their life expectancy, but the overwhelming majority of these non-serviceable bearings will not be retired when they should be.
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GT3 Recaro Seats - Boxster Red
GT3 Aero / Carrera 18" 5 spoke / Potenza RE-11
Fabspeed Headers & Noise Maker
BORN: March 2000 - FINLAND
IMS#1 REPLACED: April 2010 - NEW JERSEY -- LNE DUAL ROW
Last edited by Perfectlap; 07-26-2013 at 12:00 PM.
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