The owner of the 2002 C4 I am trying to buy has shown me receipts for a new motor he had installed in 08. His old engine had IMS baring failure and was ruined. The papers say this was a replacement engine from Porsche and I have a printout reflecting the new motor serial number. The seller told me that the shop said that this new engine (made in 08) would no longer have the IMS baring issue. Could this be true? Anyone hear that Porsche replacement motors have address the baring problem?


Thanks!

 

That new (or more likely remanufactured) engine still has an IMS bearing, it is the larger single-row bearing and while it is less likely to be an issue than the one in the original engine of that year car, it is still possible for it to have the failure issue. As opposed to older engines, in this engine with this newer bearing it is more difficult to replace the bearing, i.e. it requires disassembly of the engine to do so as the bearing is larger than the access hole and thus cannot come out that way.

I have the same thing in my car ('02 car, replacement engine in '09) and am not concerned about it. I realize my failure to be concerned will not have any effect whatsoever on whether or not you are concerned about it :-) I follow the conventional wisdom prescribed within these pages of trying to keep the RPM's over 2500, and generally trying to drive it as if I stole it (but safely and legally at all times of course).

 

You still have an IMS bearing.

Replace it whenever you do your clutch. Try not to worry about it.

 

Walter Rohrl,

Right now the replacement engine has 20K and I was more worried about resale than it failing again. I though it would be nice to say that the problem was addressed.

The thing that disturbs me about what you said is that the "new" motor now has a baring that can't be replaced? There are kits like LN engineering kit that made replacing look easy to me. Do you know how I would know if this block is one of the ones where you can't pull the IMS?

PS:
are you saying lugging this engine is what causes some of the issues?

 

It's not the block, it's the bearing itself. The hole at the end of the block is the same for all, the later bearing itself is of a different diameter. As Porsche developed the engine, as they remanufactured them, they switched to the newest production bearing during the reun, over the years there were several changes. An engine from '08 (assuming it was reman'd in '07 or '08 would have had the latest 997 bearing instead of the 996 bearing (and some 997's have apparently had bearing failure). I'm not really explaining it well, but the LN Engineering Website has a good explanation of the various bearings and the issues with the larger one. Apparently it IS theoretically possible to get it out of the hole, but the way I understood it, it somehow involves crushing it inside the engine using s special tool and then getting it out somehow. I'm not a total expert on this and don't pretend to be, just passing on my knowledge and fairly sure that I am not incorrect. (But if I am wrong, I do welcome someone pointing it out and setting me straight, but please be gentle...)

 

My research (mainly this website) indicates that using rev's higher than 2500 increases the possibility of the engine "splash" lubricating the bearing. The benefits and reality of this is apparently somewhat debatable based on the location of the bearing relative to any "splashable" oil but that's the generally accepted recommendation, i.e. try to cruise at least at 2500 rpms, don't be doing 55 on the freeway in 6th gear etc. Again, I have not myself disassembled one of these engines myself or even held one of these bearings in my hand. However after reading a lot about it, if I still had my original engine I'd be replacing the bearing, with this engine I am not worrying about it. Cost to replace vs probability of the latest bearings failure leads me to believe that the cost is not worth the potential payoff. This could be foolish on my part long term, but statistically I am going for it. I have plenty of insurance for plenty of things in my life that I could not cover myself, but if this engine fails, while I would certainly notice the hit to my pocketbook, life would go on even though I'd probably be driving the minivan for awhile... :-) but I'd fix it or replace it and then go on driving it. Actually I'd probably buy a wreck with documentation and transplant that engine. It's like the old movie with the great title: "Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb..."

Not sure if any of that helps but I had the same questions last year when I bought my car.

 

I re-read the LN site and now have no idea where I saw the thing I mentioned about "crushing" or destroying the larger (newest-style) bearing to get it out. Could have been an article in a British Porsche magazine or another site, not sure anymore except I did see it...somewhere. If anyone else knows about this, please post.

LN currently says if the engine is from '06-08 the bearing is not serviceable without disassembly of the engine.

In reference to your concern about resale, I took the fact that my car had a newly remanufactured factory engine with 5000 miles on it (and 63K on the chassis) as a huge advantage over other cars that had 63,000 miles on their original engine (without a huge increase in the price). It made the car significantly more attractive to me. I'm not sure if everyone else would agree with me, but I don't see why not. If the engine was merely rebuilt or a used engine installed by someone without a widely known great reputation, that'd be a different story.

 

Even if the M97 bearing were destroyed or "crushed" its outer race is still the largest diameter of the unit and would remain in place. I'd never consider such an exercise, especially when we can disassemble the engine so easily and reassemble it with another shaft.

Crushing things inside an engine is not a precision activity.

 

Jake,

So lets just say that the M96 IMS is regular maintenance item... interval every 50K (stock bearing)

What would be the replacement mileage for a LM M96 bearing be?

What would be the replacement mileage for a stock M97 type bearing be?

Thanks!!

 

OMG!!! 997s can have bearing failures?!!! When will it ever stop?

To the OP, don't worry about it. Yes, it's possible the bearing will fail. It's also possible you'll be struck by lightening. I hope neither happens, and I doubt either will.