IMS bearing question

[mikefocke]

The original bearing and its associated mounting contains several failure causes, not just the one caused by bearing wear. Look at the description of some of the kits to get hints of which components they have found it wise to upgrade.

There are widely circulating instructions on how to replace an IMS bearing that are wrong. Beware.

Consider the cost and time to acquire a complete set of (or to make) tools. There are specialized tools recommended. Sometimes you can rent them for one time use.

[maytag]

Originally Posted by mikefocke

Consider the cost and time to acquire a complete set of (or to make) tools. There are specialized tools recommended. Sometimes you can rent them for one time use.

Or if you're handy: Build your own. Once you SEE the tools, you realize how simple they are.

[911monty]

Originally Posted by mikefocke

The original bearing and its associated mounting contains several failure causes, not just the one caused by bearing wear. Look at the description of some of the kits to get hints of which components they have found it wise to upgrade.

There are widely circulating instructions on how to replace an IMS bearing that are wrong. Beware.

Consider the cost and time to acquire a complete set of (or to make) tools. There are specialized tools recommended. Sometimes you can rent them for one time use.

Originally Posted by maytag

Or if you're handy: Build your own. Once you SEE the tools, you realize how simple they are.

Did you guys look at the pictures in his post that clearly shows the IM shaft and bearing in his hands? Specialized tools, instructions???? But yes new bolt and cover would be a good choice.

[Homeoboxter]

Originally Posted by BFeller

Which oil you going to run?

I`m so far from that stage that I haven`t even thought about it. Why are you asking?

[Homeoboxter]

For the reassembly, is there a real service manual available for the engine? I bought the Bentley workshop manual as that was the most recommended, but basically it says not much about the engine. I will need torque settings, timing chain instructions, etc..

[BFeller]

Originally Posted by Homeoboxter

I`m so far from that stage that I haven`t even thought about it. Why are you asking?

Just playing around, Because oil discussions get as confusing as IMSB discussions.

[JFP in PA]

Originally Posted by Homeoboxter

For the reassembly, is there a real service manual available for the engine? I bought the Bentley workshop manual as that was the most recommended, but basically it says not much about the engine. I will need torque settings, timing chain instructions, etc..

That information was never published by Porsche. Jake Raby published books on the subject.

[BobRickel]

Your original question was asking if anyone had experience with replacement bearing kits. I installed the EPS IMS kit in my 1997 Boxster about 3 years and 35K miles ago. I have not had the first problem with it and the peace of mind knowing it is not going to be a problem releases me to enjoy driving the heck out of my Boxster.

[BOOTLEG]

Thanks Bob. That was exactly what I was looking for as I am mulling the variety of options. Short, factual with no malice towards others.

[elgyqc]

I have not been on the board long, but when I bought my first boxster the IMS paranoia drove me to read a lot on the question. The result of all that reading was that I am no longer paranoid and I don't feel it is necessary to immediately tear my cars apart to replace the IMSB. The clutch on my Blue Boxster feels tired so I am seriously considering doing the clutch and IMSB on it this winter while I am getting the maintenance up to date.

I was impressed by the videos made by Ben Burner on the IMS. He sourced the bearing and other parts himself, built his own tools and did a whole series of videos that go from the choice of bearing, tear-down and reassembly and cost breakdown. I like the way he approached the problem and will probably follow his example. This video explains his choice of bearing:
https://www.youtube.com/watch?v=IxdvSq_byZw

Now just give me a minute to hide behind a brick wall...

[paulofto]

Originally Posted by elgyqc

Now just give me a minute to hide behind a brick wall...

Hilarious!

Safe place until a grenade gets lobbed over the wall!

[thom4782]

Words are cheap There's theory (opinions). There's reality (statistically verifiable failure rates from actual installations). They are not the same!

So ask the various IMS suppliers how many of their units have been installed. Ask what their failure rates are? If they won't or can't provide you with statistically reliable numbers, they are just talking theory.

Theory is great. Just know when you put an IMS in your car, then theory turns into an experiment, which may or may not work out. And if the experiment fails, it will cost you thousands to remedy.

[Homeoboxter]

Originally Posted by elgyqc

I have not been on the board long, but when I bought my first boxster the IMS paranoia drove me to read a lot on the question. The result of all that reading was that I am no longer paranoid and I don't feel it is necessary to immediately tear my cars apart to replace the IMSB. The clutch on my Blue Boxster feels tired so I am seriously considering doing the clutch and IMSB on it this winter while I am getting the maintenance up to date.

I was impressed by the videos made by Ben Burner on the IMS. He sourced the bearing and other parts himself, built his own tools and did a whole series of videos that go from the choice of bearing, tear-down and reassembly and cost breakdown. I like the way he approached the problem and will probably follow his example. This video explains his choice of bearing:
https://www.youtube.com/watch?v=IxdvSq_byZw

Now just give me a minute to hide behind a brick wall...

I like this guy, he spent a considerable time on this matter. I saw another video from him in which he cut a bunch of IMSBs apart and looked into them. I agree with him, it`s ridiculous how much these "solutions" cost for a car that`s worth not more than 5k. I have read numerous articles on the web on replacing the IMSB and the original two-row bearing that was replaced was in nearly perfect condition.

[Homeoboxter]

I liked the youtube video, I saw another one from him where he cuts IMS bearings apart and looks into them, that`s a good one, too. I`ve seen many reports on the web about replacing the original IMSB that was otherwise in perfect condition, especially the dual row ones. The original ones apparently last for 100k miles at least, and afterward when they get replaced to a new one, those cars are still running within the next 100k miles probably (or at least cars over 200k miles are rare), so there`s no way to really tell if any kind of IMSB upgrade is better that the original 2 row bearing, which cots like $50. And I agree, creating hysteria and selling "the solution" for $800 for cars worth 5k is just not cool. IMHO.

[mikefocke]

I went to a homeowners' association meeting the other day and they were still discussing the same issues that were being discussed 7 years ago. With no more expertise or research applied to the subjects.

[thom4782]

The hysteria arises because 1) the timing of IMS bearing failures is extremely difficult to predict and the 2) cost of failures is unreasonably high given the market value of these cars.

Data suggests the following failure mechanism is the most likely. IMS bearing seals degrade and allow the internal lubricant to wash out. Unfortunately, the leakage is too small/slow to allow mist engine oil to replace the loss. When this happens, the resulting friction increase leads bearing spallation, which then leads bearing failure.

Timing is hard to predict because contaminants in the oil of low mileage cars that sit idle for long periods accelerate seal degradation. High mileage cars, typically daily drivers that get up to operating temperature frequently, slow seal degradation markedly. Hence, IMS failure occur in both low and high mileage cars. There is no magic number after which these cars are safe.

Single row bearings fail more frequently than dual row bearings because they are more highly loaded and they see the effects of poor lubrication more dramatically.

People can increase their odds of avoiding an IMS bearing failure when they replace the original by taking the following steps:
1) install a bearing that can withstand higher loads, e.g. ceramic over steel, dual over single, etc.
2) ensure that the bearing receives adequate lubrication, e.g. is unsealed so it receives mist oil or is oil fed

In my case, I installed the IMS solution because it was capable of bearing the highest loads, was oil fed, and if it did fail it was the one design that was most likely to keep the engine from jumping timing.

[BOOTLEG]

OK, thinking "Experimental" - has anyone removed their 2 row and after finding nothing wrong, simply stuck it back in?

[Homeoboxter]

Not sure it`s a good idea to remove a bearing and place it back in since the axial force used to pull it out from the shaft may cause detoriation leadng to premature wear. Once you remove it by forcing it out by prassing the inner ring axially you better replace it to a new one.
My IMS was full with engine oil, and I read the same in all of the reports of bearing replacement. In my understanding filling the shaft with oil can only occur from the flywheel side through the bearing, if the pump side is not punched through. So in all these cars the bearing lost its original lubricant long ago and was washed out with engine oil. My impression is that, as the IMS sits on the bottom of the engine, it`s close to the oil level in the sump so it can get excessive oil by splashing. This may be sufficient if you remove the seal and keep the oil level close to maximum. I`ll look more into this next weekend since now the engine cases are apart.

[JFP in PA]

Originally Posted by BOOTLEG

OK, thinking "Experimental" - has anyone removed their 2 row and after finding nothing wrong, simply stuck it back in?

That would probably be fatal. During the extraction process, the balls, cages and rear race are subjected to extreme loading forces, distorting finished surfaces and pretty much destroying the cages. The center bolt is also subjected to loads it was never designed for as well.

[Geof3]

Originally Posted by Homeoboxter

Not sure it`s a good idea to remove a bearing and place it back in since the axial force used to pull it out from the shaft may cause detoriation leadng to premature wear. Once you remove it by forcing it out by prassing the inner ring axially you better replace it to a new one.
My IMS was full with engine oil, and I read the same in all of the reports of bearing replacement. In my understanding filling the shaft with oil can only occur from the flywheel side through the bearing, if the pump side is not punched through. So in all these cars the bearing lost its original lubricant long ago and was washed out with engine oil. My impression is that, as the IMS sits on the bottom of the engine, it`s close to the oil level in the sump so it can get excessive oil by splashing. This may be sufficient if you remove the seal and keep the oil level close to maximum. I`ll look more into this next weekend since now the engine cases are apart.

Maybe just buy the cheaper Porsche bearing and plan to make it a maintenance thing with clutch jobs? Is it worth more to put in a more expensive bearing? Who knows at the end of the day. If it were me, and I were rebuilding the engine anyway, I'd probably go all in and do the Solution and be done with it. Simply because you are there, and trying to justify cost vs value is pretty pointless as rebuilding the engine takes that discussion right off the table.