This November I purchased my first Porsche, a 2004 C2 6 speed with 30K miles. The car’s history is as follows: first owner drove it 3 years (12K mi) when the IMS bearing failed and the engine was replaced under warranty. Soon after she was injured and the car was stored covered in a garage until 2010 (2yr 8mo) then sold to the PO I purchased it from. He is a rennlist and PCA member with (2) 944’s that he raced. His PPI and subsequent 3 yrs of driving 18K mi required only one minor repair, tires, and oil changes. My PPI and Post PI (paranoid I know) were also clean. I am very happy with the car and believe that I got a good car for a good price (I don’t want to hear otherwise).

So my questions are:
Since the engine was replaced in 2007 by Porsche OEM parts were used for the IMS bearing but did they use the “improved” version or the original? How would I determine this?

Could they have replaced the 996 with a 997 (highly unlikely)?

Is there any reason to expect that the replacement engine is superior or inferior to the original?

Appreciate any constructive comments.
Steve

 

By 2007 any factory replacement engine would have any and all improvements up to that point in time including the larger "improved" bearing found in the 997 in 2007.

 

A fixed IMS bearing that you have to crack the block to change is not what I consider an improved version. Bearings will not last forever.

 

This may not be so great after all. Like others have said, you now have a six year old engine that will need the case split to replace the IMSB which is now a PM item. (at least you can remove the bearings outer seal). Let the panic begin.

 

He hardly has any miles on it, the engine will last for a very long time.

 

Relax and enjoy your car. You have 18k miles on it FFS.

 

Take a look at the series number on the oil pan, if it's after M9603AT66565897 you most likely have the bigger bearing/ 997 assembly.


I've got 60K on a motor that's identical to yours, 114K on the chassis

 

If you find that you have the improved bearing, your comfort is knowing that the improved bearing appears to be much more reliable than any of the previous bearings.
While the new bearing requires much more expense to replace, the likelihood of failure is much lower, and the other forum members are weighing in on that trade-off.

I have a similar situation to yours where my engine was rebuilt in 2011 (by the prior owner) with the newer bearing, and personally I take comfort in the improved bearing.

 

OP, if you find that you have the non serviceable 997 style bearing and you're still uneasy about it, you can always go the DOF route which is also made for 997 engines.

http://tunersmotorsports.com/?page_id=103

 

I see no need for panic. Have no intention of doing a PM IMSB. Will drive it, maintain it, and enjoy it.

Excellent point I will file away

As I see it I have a 3 yr engine with 18 K on which I will put another 18K over the next 3 years. Still a low mileage engine.

 

enjoy the 996 guys... these are awesome cars. My advice, do not lug these engines, stay in the high RPM range.

 

My situation is almost identical. I'm the second owner of a 2003 996 with about 30,000 miles. I bought the car back in October. According to dealer service records, original engine was replaced due to IMS bearing failure in 2007 at about 23,000 miles. The clutch was also replaced at the time. Replacement engine serial number indicated a rebuilt 2005 engine. I just had a Porsche specialist here in New Jersey drop the trans to check the IMS bearing-it is the "improved" large bearing. They just closed it back up and told me not to worry. I may try a DIY install of the DOF system next spring, but I feel a lot more confident now. I won't complain-turns out I have a low mileage Porsche 911 with an almost new engine and clutch!

 

Again the earliest confirmed rebuilt number that got the new 997 IM assembly is M9603AT66565897. Next time I've got the car up, I'll shove a boroscope into mine (serial number couple hundred after the number above) to confirm.

 

+1 on this

 

I challenge anyone to find more than one documented IMSB failure on a big bearing engine....I don't want stories lads - I want evidence.


I tried this once already - I got one response, but that's it. The big Porsche bearings are simply not prone to failure.

I have a big bearing motor in my car with 80,000 miles. Not a lot I know, but it also wasn't weeping or leaking or looking anything but healthy when I replaced my clutch last year.

edit

That DOF looks pretty cool actually, I hadn't heard of it before this. Maybe at the next clutch change, although even these guys say:

"We have even seen IMS bearing failures on early 997/987 models...."

and we all know by now that the early 997 engines used the smaller IMSB.