Planet-9 Porsche Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
75 Posts
Discussion Starter #1
I know there is a lot said online but still, the test of time is ongoing. I was wondering. Is it that the IMS will fail no matter what on the M97 engines, and bores score just depending on mileage? Are all cars on the same spectrum - from zero to scoring and burning oil until the pistons just lock? Are the bearing balls just wearing and wearing with mileage so that failure is inevitable?

I'm quite new here and will appreciate your opinions,

Thanks.
 

·
Registered
Joined
·
51 Posts
I have a 987.1 Cayman S as well. In my reading and understanding, the IMS bearing was designed to be a larger, permanently lubricated bearing, similar to a wheel bearing. It would stand to reason that if a wheel bearing, exposed to the elements, can last for 200,000 miles, then a bearing splashing around in oil should have no problems. Right? The problem comes from the fact that the bearing is mounted into the end of the intermediate shaft. This shaft is hollow. When the motor and shaft heat up and cool down, the air in the shaft expands and contracts. This pushes air, motor oil and the lubricating grease in and out of the bearing. Over time, there is no grease left in the bearing and only some amount of old motor oil. With the ridiculously long oil change intervals recommended by Porsche and the tendency for these cars to sit for long periods, this small amount of oil becomes a less than ideal lubricant. The bearing is more than strong enough to handle the load for which it was designed. But, once it looses it's lubrication and starts to run dry, it is only a matter of time and miles (this time and miles could be over 200,000) before it starts to pit and fail. There are some companies that will sell you different solutions to this problem. Some of these solutions will direct a pressure feed from the engine to pour oil onto the bearing continuously. If the engine can have rod bearing failure and bore scoring from a less than adequate oil feed, pumping some of this oil to the IMS seems like it could be dangerous. LN engineering recommends that the front seal be removed from the bearing. This will allow fresh motor oil to splash into/onto the bearing somewhat continuously. This is not ideal, nor is it any guarantee against failure. I removed mine and inspected the bearing as best I could at about 80,000 miles. There was an obvious sucking, vacuum sound when I removed the front seal. The bearing seemed fine. I could not detect any pitting or slack. Will it fail? I don't know, but I really don't think it will. My car now has 85,000 miles. Most of these are very spirited miles. I change the oil often. It is very easy to change and Walmart sells 5quarts of Mobile 10W/40 for less than $30.

As for bore scoring, I'll let someone else answer. But, I think that is talked about more than it happens (it is probably more prevalent than non-986 IMS failure). Also, it may be more related to HPDE's and over-revs. I have been to 2 track days, so far. I will say that I was surprised at just how fast drivers push their cars at these events. Even in the green group. You could never do anything close to that kind of driving on the street, no matter how much disregard you may have for traffic laws. The guys on the 6 O'clock news running from the cops don't drive that hard.

If your cars checks out fine now, change your oil regularly, drive it like you own it, and you'll probably be just fine.
 

·
Registered
Joined
·
2,192 Posts
IMS failure in the 987 series is ridiculously overstated. It's reported, by very reliable sources and experience, to be less than 1% of all 987s. You're just as likely to be hit by lightening. Bore scoring is an issue I haven't done any research on but from all appearances, it seems to be track use related, for the most part, and still an issue that under 10% seem to experience (my own estimate based on all the Porsche blogs and forums I review regularly).
 

·
Registered
Joined
·
818 Posts
Bore scoring is a whole different issue for the M97 engine. Jake Ruby has a 4 part u tube on this subject. In part 3B, Focus on Bore Scoring Symptoms, Jake covers, Ferostan coating, Shooty tail pipes, Oil Consumption, Oil change intervals, Black engine oil, Durametric misfire codes, Wear debris.
 

·
Registered
Joined
·
463 Posts
I'm no expert, but my impression after having watched the video series on bore scoring is that it is a tolerance build up type of issue, where if a few things go against you, you could have a problem, but if not, it should never be an issue. Over the years I've owned my 07, I've read MANY MORE comments about the IMS issue than bore-scoring, but more people talking about actual bore-scoring failures than IMS failures. I actively keep my brain from worrying about either issue, helped by the fact that I have a never-tracked 2.7l engine.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #6
Apex - thanks for the excellent recommendation to watch the videos. What a crapshoot. My girlfriend was laughing at me because it looked like I'm watching video lectures before some exams - we are both medical doctors and this format is familiar. I see an observation bias of people like Jake, who receive only the worst cases one after another. On the other hand, like we say in the medical world - 5% chance of dying is not high for someone else, but when it happens to you - it is high enough.

It makes me reconsider tracking the car before I save money for a rebuild.
 

·
Registered
Joined
·
818 Posts
Borski- Just being aware of the potential risks are important to know. You can then try to avoid possible causes that are not reversible.
 

·
Registered
Joined
·
21 Posts
I know there is a lot said online but still, the test of time is ongoing. I was wondering. Is it that the IMS will fail no matter what on the M97 engines, and bores score just depending on mileage? Are all cars on the same spectrum - from zero to scoring and burning oil until the pistons just lock? Are the bearing balls just wearing and wearing with mileage so that failure is inevitable?

I'm quite new here and will appreciate your opinions,

Thanks.
An excellent question, and I don't have an answer, but if you, as i have, carefully read everything, and try to understand the primary cause or circumstances that lead to IMS failure, it does seem it's just a matter of time. Nothing I've read has supplied a definitive why or why not it happens. Consequently, I parted with a 996 (even with the IMS upgrade), but taking a gamble on 987 (base ), since I just like the car.
 

·
Registered
Joined
·
463 Posts

·
Registered
Joined
·
10 Posts
my 06 S has 87kmiles with 1000 miles on three local tracks. It's general driven very hard, as it's a toy. I have no problems! I have a magnetic drain plug that I pull about every 2Kmiles and swap for the stock one losing about a 1/4 qts, I inspect it and put it back. I figure that I can catch a IMS problem before it turns into a mess. Bore scoring is more common in cold climates, I also think it can get started if you let the engine idle when cold, as the high amounts of fuel needed to idle a cold engine washes off the oil film in the cylinders and contaminates your oil with gas.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #11
@KKiani - I was waiting for examples like yours, I've heard them before. Some crucial factors make these engines work without wearing down. At least not as much as its dreaded in many stories.
 

·
Registered
Joined
·
818 Posts
You can google "how many miles on your 987.1? Its an older P9 thread, but some answers will surprise you.
 

·
Registered
Joined
·
75 Posts
Discussion Starter #13
@Apex, I went for it and it is impressive. There is a guy speaking about rebuilding the engine to 4.0 and not wanting to switch to a GT4 instead. It is a puzzle, 987 with a custom built race engine sounds amazing. If you can afford it - it is a win win situation.
 
1 - 13 of 13 Posts
Top