Looking at 07'-08' 987 Cayman Base - IMS Question

[Atlmike]

In preparation for acquiring an 07'-08' base Cayman early next year, I bought Wayne's 101 Projects for your Porsche Boxster to get a feel for what maintenance I could comfortably perform myself. I've read about the IMS issue here, in the book, and in Excellence. The bearing design in the 06'-08' 987's is mentioned as being irreplaceable in Wayne's book. Does that mean that any issue with the IMS bearing would necessitate a complete replacement engine?

Thanks for all your insights,

Mike

[mikefocke]

Can the IMS on a third generation IMS (large single bearing) be replaced? Yes, but it involves a complete teardown of the engine block involving removal of the engine from the chassis. LN would take your IMS shaft and redo it with a new ceramic bearing and return it to your mechanic for installation in the split block they have lying on their workbench. Only someone very experienced in the engine internals should attempt this. A few have been done, but not many. $$$

Do the third gen bearings fail as often as the earlier ones? No. The exact frequency is unknown.

[Atlmike]

Thanks mikefocke,

The lower instance of bearing failure on the 987's has me feeling much less apprehensive about picking up an 07'-08'. Everything I've read seems to point to 10-12% failure rate of the 01'-05' 986 bearings, with the 987's and double row, early 986's having a hypothesized failure rate of 1-2%.

Thanks again,

Mike

[Sapientoni]

Hi Guys,
I am currently engineering/investigating an in car modification to allow changing of the 2006 + IMS bearing. I have acquired a 2006 S with some kind of engine failure and it will be modified to MY specs. I'll let you know how it turns out. This modification may be my retirement job.
Later dudes!

[JFP in PA]

Originally Posted by Sapientoni

Hi Guys,
I am currently engineering/investigating an in car modification to allow changing of the 2006 + IMS bearing. I have acquired a 2006 S with some kind of engine failure and it will be modified to MY specs. I'll let you know how it turns out. This modification may be my retirement job.
Later dudes!

Good luck, but I believe Jake Raby has already beaten you to the punch.......

[Sapientoni]

You can't remove and replace the IMS with the engine together with his fix, I don't believe.

[JFP in PA]

Originally Posted by Sapientoni

You can't remove and replace the IMS with the engine together with his fix, I don't believe.

That is the general consensus, but I have also heard that Jake has found a way, but one that in his words "ain't pretty". I wouldn't be surprised if he had, he is pretty creative with these engines. You might want to do some searching in that area before you risk your retirement on it....

[tonythetarga]

Back to the OP question. If you do get the car, you might want to find one with reasonable mileage and then have the bearing seal removed to allow oil to freely lube the bearing. The failures involve just enough oil to get behind the seal and melt away the grease but not enough oil to lube the bearing. The trans has to come out, the flywheel off and the IMS door removed to expose the bearing seal for removal. Another company has an oil fed system with filtered oil being sent to the bearing, however, the seal removal works well as long as you frequently change the oil.

[EBS_Don]

Well, you're talking about pulling a 62mm OD bearing through a 58mm hole. Machining the bore to clear the bearing would make quite the mess inside the case and then you would have to make a billet flange with a custom seal to cover the new hole you made. The risk of particle contamination would make the use of an open faced bearing just about impossible. Other solutions would have to come into play...

[Atlmike]

I realize this is complete Monday morning quarterbacking, but I wonder why Porsche, after all the issues with the IMS bearing in the earlier cars, didn't make it easy to get at in the 06'-08' cars?

[Sapientoni]

This problem is not reserved just for the Cayman and Boxter. The 996's have the same engines ergo, the same problems.

[Sapientoni]

The IMS bearing fact, it's a roller bearing. The failure point is the metal surface of the balls and races breaking up or "spalling" after a few billion contacts and microscopic flexing of the surfaces. Lubrication might not even be a factor. The inner race of the failed one I removed showed damage while the surface on the non pressured side of the race looked new. I don't know how many of the current "eternal fixes" have done 8 years in service or how many miles. Even hours of dyno are not the punishment the common engines face as a daily driver.

[howe00]

Lubrication is NOT the problem the bearing CAGE is. Install a full complement ball bearing and its fixed for good.