997 engine life span with IMS?

[Eat-um-up]

I recently learned that my newly acquired 2005 997S could be subject to the smaller IMS and may need to have it changed. Sorry to ask these questions for the bazillionth time. Im just not clear as i mostly get 996 results in search and the 997 stuff sort of says, large bearing move on.

What my research has found that this is true for only early 2005's made before march 2005.

So far I have not been able to figure out my cars build date (cant find the sticker) and the engine number is M9770168511872.

This post suggests that my engine has the large bearing that can't be replaced without doing an engine rebuild.

first off, am i right in that conclusion that my engine should have the larger IMS?

If that is the case then there's no point in changing the bearing until its time for a new engine.

I have also read that its a good idea to have the bearing seal pulled from the bearing.

just how eager should i be to take the car in and have the seal pulled? or should i just wait until there is another reason to pull the trans?

I have a manual and clutches seem to last quite a long while. Is there any consensus on how many miles that larger IMS is good for?

[JFP in PA]

Originally Posted by Eat-um-up

I recently learned that my newly acquired 2005 997S could be subject to the smaller IMS and may need to have it changed. Sorry to ask these questions for the bazillionth time. Im just not clear as i mostly get 996 results in search and the 997 stuff sort of says, large bearing move on.

What my research has found that this is true for only early 2005's made before march 2005.

So far I have not been able to figure out my cars build date (cant find the sticker) and the engine number is M9770168511872.

This post suggests that my engine has the large bearing that can't be replaced without doing an engine rebuild.

first off, am i right in that conclusion that my engine should have the larger IMS?

If that is the case then there's no point in changing the bearing until its time for a new engine.

I have also read that its a good idea to have the bearing seal pulled from the bearing.

just how eager should i be to take the car in and have the seal pulled? or should i just wait until there is another reason to pull the trans?

I have a manual and clutches seem to last quite a long while. Is there any consensus on how many miles that larger IMS is good for?

2005 was a transition year, meaning the car could have either bearing in it. The worse news is that the ONLY way to know which bearing is in it is to take it apart and look. All other "internet methods" are wrong, taking it apart is the only way.

[tonythetarga]

+1
Here’s the good news. It takes about 4-5 hrs of labor to R and R the trans. Check which bearing you have. If it’s the 996 style, replace with an LNE bearing. If it’s the big one, pull the seal.
You’ll sleep much better. If you’re tracking the car aggressively, then the equation changes, but as a driver you should have no worries.

[Eat-um-up]

hmm. i am hoping that I can avoid pulling the trans just for that. The dealership did the clutch and main seal on it earlier this year.

I did go by the parts counter at the dealership this morning and had them look up the IMS bearing part by my VIN.

They were unable to find a bearing listed. the exploded diagram showed the cover > seal > Intermediate shaft. No bearing listed or depicted.

Does anyone know if this is indicative of being the larger bearing or would i see the same result from the part counter if I had been looking up say a 2004 part?

[tonythetarga]

Reread JFP’s response, then search his posts. He’s not guessing. The VIN or parts book won’t give you the answer. It needs to be physically inspected.

[Eat-um-up]

Originally Posted by tonythetarga

Reread JFP’s response, then search his posts. He’s not guessing. The VIN or parts book won’t give you the answer. It needs to be physically inspected.

Theres of course no substitute for a physical inspection. When it comes to used anything you are always guessing to an extent on the products history.


But as i said, I'm tying to make a calculated guess on if i really should spend the money to have it looked at now or if I feel like I can take the risk to wait a bit.

[yelcab1]

OK, if you don't want to pay for the 6 hours of R/R gearbox to ascertain the truth, then continue driving the vehicle, change oil more often, cut open the oil filter each time to look for flakes, and check cam deviation with a Durametric every month.

[Eat-um-up]

Originally Posted by yelcab1

OK, if you don't want to pay for the 6 hours of R/R gearbox to ascertain the truth, then continue driving the vehicle, change oil more often, cut open the oil filter each time to look for flakes, and check cam deviation with a Durametric every month.

Well the plan was to have it looked at. the question really was how long can I wait since I thought all 997's were large bearings at the time of purchase. messed up my homework there. anyway, it turns out having it checked for me isn't an option.

For my situation im just going to have to "trust" that is updated since it on the production date (04/05) and the engine number. So I'll be taking your sound advice yelcab1. watch the oil, check the computer. maybe look into an extend warranty. The one shop that had any IMS experience told me to just watch the oil and shut it off immediately if the check engine light ever came on (to check cams). I guess this happened to a client once. she thought it would make it home and it didn't. He had also never heard of pulling the dust seal off the bearing too.

I do have a couple of follow up questions if anyone knows the answer.

Would you know what values or pattern I would be looking for on that deviation? still researching the Duramatic vs the iCarsoft. looking at cam data isn't something I've done before.

On my Audi the manual indicates that if the check engine light flashes, then shut the car down as its a critical failure. if its just on, then its minor and basically an emissions fault.
Does the 911 function similarly? Specifically to the cams in this case. Should it detect out of bounds would it flash or just light up?

In anyone is curious to the why I'm stuck ill explain that next. But unless im out for an engine rebuild, I am out of in town shops who will touch the IMS on my particular car.

The shops in town that service the car are unwilling to do the work to check it out. One just said they are too afraid of the job. I can admire that they recognize their limitations. The other only knows how to check by pulling the cover plate. it also involves cam locks and the whole bit. At that point the only cost difference is 5 minutes of labor and the bearing. Those are the only two shops here that I know of that work on the water cooled 911's.

There is a long story behind it involving some kit that bores out the block to make the large bearing serviceable (which he did once and does not like). He also does not want to tie up a lift while he waits for a part to come in. So rather than potentially wasting a bunch of time and a lot of money, he has opted to not accept the job.

[yelcab1]

First, it's a good mechanic that knows his limitation and is honest about the tying up the rack reason. I have only one lift, and it means I cannot do anything else if a broken car is sitting on it for any reason. I can respect his reasons.

Second, you are in Bakersfield and it's not LA or Bay Area where there are 100,000 Porsches. You might want to learn how to do this or job it out to someone who is willing to take it on, out of town even.

As for the Porsche vs Audi thing, I have both but I do not know there is a distinction between flashing vs solid CEL. Both are bad to me. I do not remember ever seeing a flashing CEL on any of my Porches, or the ones I worked on. However, if there is ever a IMS related CEL on your Porsche, it is actually too late. You are way past time to open your wallet to a large check. Don't count on the CEL to catch your IMS problem. The thing to do is to take care of it preemptively.

As for the deviation pattern to look for, you want to see no more than 6 degrees of cam deviation from perfect alignment. You also want both cams to have fairly close to each other values. Widely different values mean some kind of problems even if it is not IMS related. Chain wear, chain pads wear, tensioner assembly issues. When you step on the gas to 3000 rpm, you want to see a jump in actual cam degrees to 20 to 30 advance (don't quote me on that number, but it is big).

[Eat-um-up]

I have to agree about respecting the reasons from these mechanics. As far as out of town, that's not something that's in the cards for me logistically.

One of these days ill probably end up doing the inspection myself. I don't know anyone who has the skill set or means here.

Thank you for the information on checking the cams.

[BYprodriver]

Originally Posted by Eat-um-up

I have to agree about respecting the reasons from these mechanics. As far as out of town, that's not something that's in the cards for me logistically.

One of these days ill probably end up doing the inspection myself. I don't know anyone who has the skill set or means here.

Thank you for the information on checking the cams.

For starters send a oil sample to LN Enginneriing to have it analized. for metallic contect.

[Fighterpilot]

I am somewhat confused - which is not necessarily difficult. Most if not all 05 997s will have a M96 engine, correct? If an 05 has a M97 engine, was it a factory replacement after the lawsuit? Had the previous small bearing M96 been replaced with the newer engine? My 06 997 has the larger single race bearing, built in October of 05. The last "small bearing" M96 was engine number M96-6950745. Production of the larger single race bearing began with engine M96-6950746. My engine number is 69603037. PCA published an article regarding the class action law suit filed by an Oregon Chapter many years ago, of which, Porsche settled with some engine replacements and some LN bearing replacements. The lawsuit discovered an approximate 10% failure rate for small bearing M96s, then an approximate 1% failure rate for the larger. Anything metal on metal is going to wear, over time! Every mechanic I've talked to (mostly Porsche shops) has told me, "With your engine number, drive it like you stole it!!"

[Eat-um-up]

Truthfully I do not know if my engine has ever been replaced. I would expect not.

From what I have come to understand mine has an M97 because its an S model (3.8 instead of the 3.6). Some of the 3.8's also have the smaller bearings. based on charts in the wild mine should have the larger bearing.

But as conflicting results have been reported, its best to have a personal look for that 22mm nut. Still not sure what the lifespan of the large bearing is with the dust seal removed vs not removing it.

[JFP in PA]

Originally Posted by Fighterpilot

I am somewhat confused - which is not necessarily difficult. Most if not all 05 997s will have a M96 engine, correct? If an 05 has a M97 engine, was it a factory replacement after the lawsuit? Had the previous small bearing M96 been replaced with the newer engine? My 06 997 has the larger single race bearing, built in October of 05. The last "small bearing" M96 was engine number M96-6950745. Production of the larger single race bearing began with engine M96-6950746. My engine number is 69603037. PCA published an article regarding the class action law suit filed by an Oregon Chapter many years ago, of which, Porsche settled with some engine replacements and some LN bearing replacements. The lawsuit discovered an approximate 10% failure rate for small bearing M96s, then an approximate 1% failure rate for the larger. Anything metal on metal is going to wear, over time! Every mechanic I've talked to (mostly Porsche shops) has told me, "With your engine number, drive it like you stole it!!"

The use of either the VIN or engine numbers has proven over time to be useless in determining what style bearing is in these cars. The only way to know what you are dealing with is to pull it apart and look.