IMS bearing question

[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.

[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.

[Homeoboxter]

Originally Posted by Geof3

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.

The cheaper bearing (pelican I assume) is to be replaced in every 40k miles, costs $180 and is worse than the original (being half in size). Why not just buy a new double row bearing same or similar to the original that looks perfect after 100k?

[Geof3]

Originally Posted by Homeoboxter

The cheaper bearing (pelican I assume) is to be replaced in every 40k miles, costs $180 and is worse than the original (being half in size). Why not just buy a new double row bearing same or similar to the original that looks perfect after 100k?

Misunderstood... Yes, if cost is an issue, replace with a factory bearing and plan for maintenance. Or, since you are there, consider the $$ for the one and done. The IMS “discussion” really has become the proverbial oil thread. There are several options and price points. I think it simply boils down to which you feel the most comfortable with across the board. Overall, in terms of replacing it or not, it’s a bearing, and bearings fail. Do it while you are there.

[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.