JD ARTHUR

John, it takes a while for a failure to happen. During that time if yours is one the ones thats going to eventually fail it will be shedding metal. You will only see the metal caught in the filter, some will be bypassed and will be effing up bearings. A stock dual row lasts longer which means it can be shedding metal longer before it fails completely. Of course many bearings are doing just fine and shedding nothing. In the short time I've been on this site there's been some complete failures. The ODDS are that your car will be fine. I chose to replace my bearing and even went to the extreme of shipping my car all the way to Jakes shop. I had no metal in anything but I'm planning on keeping the car many years regardless of how many miles I drive it and I just didn't want to have the issue on my mind.

tlisotta

Thanks JD. I am in the hunt for a 2002 - 2004. I may look at 2005 997s as well. So - factoring in the cost of the replacement is on my mind. Thanks for the reply. The good news is hopefully a shop in Texas will get certified.

alpine003

This should be other members resolution too for all the worry warts on here as well. Hate to see elevated blood pressure levels, ulcers, migraines, etc . all over a car.

alpine003

LOL, I can safely say these are the "mechanics" that would least likely pass Jakes certification, let alone hand out sound advice.

5CHN3LL

I think you mean Rake Jaby.

Quadcammer

Its a completely different design for the intermediate or layshaft. Not to mention one is a plain bearing.

the ims solutions mimics this but the overall design is just different.

5CHN3LL

I see the same basic (incorrect) conclusions posted over and over and over again. While it is obviously true that the IMS issue is overblown, you guys who keep quoting "only X percent of cars have the issue" need to think that through. Only X percent of cars had the issue at a specific point in time. Time has now run forward. It's ridiculous to think that the numbers reflect current reality - so please quit it with the 2%, or 3.14%, or whatever other numbers you've cooked up in your head to convince yourself of whatever you wanted to believe.

Everyone knows what happens if something goes south, so just decide if you're willing to stomach the risk - but the fictitious stats just have to go.

aggravation

Yea, Porsche's accounting of failures is going to be low even if they aren't trying to downplay the figures.
There is no way to know how many owners had a 996, engine was destroyed by IMSB failure out of warranty period, and all they know is their mechanic told them it was new engine time and they walked away from it without ever having their incident added to the tally.

5CHN3LL

Regardless of who said what, the number of failed somethings will continue to grow over time as long as there are >0 somethings still in use. The numbers people have dug up/made up are, at best, a snapshot of reality at a specific time in the past.

johnireland

While it might be fun to psychoanalyze the posters here, it might be more productive to answer the questions.

1. Which of the "fixes" best emulates the 996 Turbo bearing lubrication design? LN? EPS? Others?

2. Which year/engines did the large single bearing come into service?

3. Which sealed bearing solution best matches or exceeds the factory OEM large bearing and can be fitted into cars with the small single bearings?

I bring up the percentages of failures and non-failures because they do reflect that some designs were better than others, and solutions that do not change the basic design may offer no more security than the original bearings.

While for the moment I am not changing my bearing, I see no reason not to continue investigating all the options that are available...and to explore more fully the explanations as to the source of failures.

Oil contamination of the sealed bearing grease is one explanation. Low oil levels leading to low oil pressure at the cam chain gear is another. Bearing design size is another (based on which version fails the most).

Saying "we already talked about it before, read the old threads" is not an answer that I find satisfactory. Those who don't like IMS threads know that they don't have to read them. Those who are curious and want to discuss it should not be intimidated by attempts at ridicule from forum members who think this is all below them.

aftCG

Yep. The low number of double row failures has an empty echo at my house, where the failure rate is hovering right at 100%.

My car was running perfectly with no rattle and I found metal in the filter (what now seems to be a small amount compared to some pictures I've seen). My pan was clean. My bearing was full of glitter, but spun "okay".

Initially I hoped to install a new bearing and flush. It was that single line item from Jake "please use a competitors product" which caused me to suck it up and tear down the engine.

Damn glad I did. My main and rod bearings were quite worn, my #6 rod bearing had taken at least one turn around the crank, two of my six oil spray nozzles were plugged solid, two barely worked. My chain ramps were quite tired.

I've had the entire mess ultrasonically cleaned (again, on Jake's advice), had my crank polished and maganfluxed and started collecting the parts.

My bearing carrier is back together and my crank spins and measures out beautifully. I have several hundred dollars worth of parts and tools on my christmas wish list. If santa doesn't come through I'll have some smoking plastic in my wallet by the new year.

DTMiller

That's a shame.

JD ARTHUR

I agree with 5CHN3LL that the percentage numbers don't mean anything. They are always changing and they were probably never accurate anyway. The bottom line as he said is "are you willing to stomach the risk". I completely disagree that it's "obvious the IMS issue is overblown" but thats just my opinion amongst all the others. John Ireland most of the answers to your questions are not hard to find, but they are all just speculation. My personal opinion is the factory had some problems with the original double row bearing but they had many many more with the single row bearing. Its just speculation but many say the sealed bearings original grease dried up, some say it washed away. Jake thinks it needs to be not sealed on one side so that oil can get on it. I tend to go with what Jake thinks since he has devoted hundreds maybe thousands of hours to this problem. However if Jake thought his fix was as good as it could get he would not have developed the SOLUTION which is a plain bearing fed under pressure. Once again I agree with him and think that is the ultimate fix for the issue. Unfortunately the engines with the original double row bearing can not be fitted with that modification. It all really comes down to what you can stomach. Plenty of owners can stomach the thing without a fix with great results some wish they hadn't, back to square one.

5CHN3LL

The Rennlist 5-Step IMSB Program

1) A guy acquires a 996.
2) The guy posts a passel of "never-before-considered" IMS theory. Also, Earth is round, fire hot.
3) The guy:
A) Retrofits bearing
B) Says, "psh" at retrofit, but magically needs new clutch within months, "might as well, since it's apart anyway"
4) The guy thinks about other stuff for a while.
5) The guy bitches about n00bs creating new IMS threads.

5CHN3LL

Alternatively, there's the accelerated program for advanced students:

1) A guy acquires a 996.
2) The guy freaks out, disassembles and reassembles his 996 so obsessively that a tweaker would be impressed, and ultimately sells it after 200 miles and $10,000 worth of preventive maintenance. Pelican and other parts vendors high-five.