"I stay away from percentages and absolute terms because none of those exist in a mechanical world ..."

just wow...

 

Thats right.. To fully understand this you'd need to live a life where you manipulate mechanical things no less than 12 hours a day, everyday and even for fun. Anything thats mechanical can fail at any time, for absolutely no reason and it doesn't have to make sense... Nor does it have to ask permission. That comes from a person who has been known to hold engines WFO until they fail just to see what breaks first.

The data to support any percentage/ statistical projections on the topic of the IMS failure simply does not exist. Three failure calls in two days are our statistics for this week and its only Tuesday.

 

Just out of curiosity, what's the current failure count on the large/nonremovable M97 bearing on late 996/early 997 motors?

 

One of the three failures I referenced earlier was from a late "big bearing" engine. 2008 with 23,000 miles for that one..

We are seeing more and more of the later big bearing failures. Like the older engines, it took us about 5 years to really see an influx of issues from the 06 and later engines. It seems the later engines have more issues with broken timing chains and cylinder failures than anything else. On the track the newer engines have significant rod bolt failure issues, thanks to the longer strokes and shorter rods the factory used that increase piston speeds and the rod bolts were not upgraded to meet the increases.. Makes no sense to me, longer stroke, shorter rod, more rod angle and faster pistons speeds, then you hang a bigger and heavier piston from it all.. Makes absolutely zero sense to anyone other than a bean counter.

 

Jake, with the earlier engine failures it seems that it's largely (not all) due to low usage/low rev cars having the failures. Do you feel the later engines suffer from the same "abuse"?

 

The earlier bearings were smaller and saw reduced surface speeds when being driven slowly.. The loads the bearing more and increases wear by reducing full film lubrication. The earlier bearings LOVE high speeds as the load is reduced and the bearing sees better lubrication.

The later bearings are larger, which increases surface speeds at lower engine RPM levels. These bearings are doing better on the street, but worse on the track.

What impacts both of these are extended oil service intervals and elevated total acid numbers in the oil which hardens and breaks down the seals that are fitted to the roller bearings, starting the Stage 1 bearing failure. The issue is the fact that a roller bearing should have never been used and it certainly had no place being sealed, or having an outer race rotation.

I have a chapter in my book on this topic.

 

Thanks Jake......couple of things.....1) when I said "later engines" I was refering to the '08 engines you mention......is that what you were referring to when you said "the later bearings are larger"?

2) You mention "roller bearings".....the IMS bearing that came out of my '03 is/was a ball bearing, not roller........where's my disconnect with what you said?

3) So, it seems that if you keep the revs up and change the oil at the proper interval, or earlier.......the world is a wonderful place?

Best Regards

Les.

 

All engines post 2006 have the larger M97 style bearings. These cannot be retrofitted as the bearings are larger than the access port in the case.

A ball bearing is a type of roller bearing. Some have needles, some have *****, but both are roller bearings.

Thats not magical.. It all boils down to how good your luck is.

 

Ok, never heard that but as lon as we know to what we're referringm that's fine.

So the design is inherently flawed and it's just down to dumb luck whether or not your engine blows up? If so, why spend any $$ on these not inexpensive upgrades?

Best Regards

Les.