pogo993

I am looking for a 997.

Regarding IMS (I know, do we really need to go there again...) But this is a good question....

Would is make sense to look at 65K - 80K mile cars over 25K-40K Mile models.
If IMS was going to be an issue would it have already happened by say 70K?

If it goes and I'm rebuilding an engine, would saving some money on the buy (getting a hire mile car) make sense? I would normally look at lower mile cars but in this case would higher maybe be better.
Am I way over thinking this thing? Does the internet have me needlessly spooked on this issue .... maybe should shut up and buy a car?.....

semicycler

Honestly the IMS bearing is not an issue except perhaps for early 2005's with the smaller, replaceable bearing. If you are truly spooked about it, look at 997.2's instead starting with MY2009. They do not have an intermediate shaft, so no IMS bearing. Or look at early 2005's and plan to replace the bearing proactively building that into the price. Or buy a 2005 that was already done. So yes you are overthinking the IMS issue for 997's.

But bore scoring is an issue for 997's. Why it occurs is not clear. It's a low percentage failure but a very costly one. I don't have numbers but would bet it's far less than the IMS bearing failures on the 996's. Due diligence during your hunt is important. Check the DME overrevs, check the service history or lack thereof, and pay extra attention to cars stored outside and started in below freezing weather. I'm not saying avoid these cars because the true cause of scoring is unknown - these correlations to a failure are loose at best. Just make sure the PPI is thorough and you can purchase knowing the car was well cared for. And if you find a gem and truly want piece of mind pay to have the cylinders inspected with a camera during the PPI.

tomc_mets

^ Great advice. Pay the extra dough, & go 997.2.
T

Ben Z

On mid-'05 through '08 cars, the IMS bearing is much beefier but the same design. That means it's vulnerable to the same processes that destroy the smaller bearings, it just takes longer. Maybe so long that it never happens before normal wear and tear necessitates a rebuild. But if it's going to happen, it would happen at higher mileage than the smaller bearing.

Bore scoring seems to be variable, but it is a progressive process too. Perhaps being started a lot in sub-freezing temps quickens the process, but my piston skirts were showing scoring (an early sign prior to actual bore scoring) in the low 60K mile range, and my car has never been out of the tropics.

As for the economics of buying a high-mileage car hoping to mitigate costs in case of an engine rebuild, remember that the rest of the driveline, all the peripherals, and every other mechanical bit also has a finite life, and those will have also gone the added miles.

Dennis C

I think the IMSB issue is overblown in general. I know that it is a real issue and that it definitely happens to some people, but I think the vast majority of 996 owners and 997 owners have never heard of the IMSB and never have a problem. I owned a 2002 C4S, a car that came from the factory with the smaller single-row bearing. This was apparently the most likely IMSB to fail. I had it changed to the LN ceramic bearing proactively at about 125K miles when my clutch was changed. My original bearing had no signs of impending failure.

I think you should just find a car that you like, and buy it. Don't overanalyze it. There are very few people who ever experience the joy of shopping for a Porsche. Don't ruin an otherwise fun experience by thinking about failure modes. Every single Porsche that you consider has some kind of potential failure that could cost you a significant amount of money. Do your best to minimize your risk, and enjoy the car!

Own Goal

Read those stickies at the top of the 997 forum. Might also go to the L&N site since they are the pros on fixes I think. All that said, my latest is a 997.2, my last was a '06 Gen 1 Cayman S with M97 3.4. It was fine as long as I had it with no problems.
Right now you can get a base 997.2 in low $40's with less than 50k miles if a manual. Loaded up S with PDK more like low $50k and up. If got a nice clean 997.1. will still be out mid to upper $30's. Sort of easy choice all things considered.
Oh, I took the cold weather car cylinder deal to heart when shopping. In Texas so bought a Texas car. Fla or Ca would have been fine also.

Ben Z

My car has never been north of Sarasota and the precursor to bore scoring (piston-skirt scoring) was evident by the low 60K's. Perhaps had it been in a cold climate it would have had scored bores and been using oil by that mileage. So based on my own experience I feel like cold weather operation may merely accelerate the scoring problem. However (and I could be mistaken) the .2 engine has different cylinder lining material and water jacket configuration, so M96/7 data would not apply to the 9A1 cars.

NavyHorn

Pogo993,

I'm one of the newest 997.2 owners on the forum, but let me offer this. I was petrified by all these potential pitfalls, and it kept from buying for quite a while. Ultimately, I found the combo I really wanted, got a PPI, bought a 2/24 Fidelity platinum warranty, was reassured/bolstered by several Rennlisters (one in this thread), and have been smiling ever since.