Another IMS bearing thread

[thom4782]

JFP's implied guidance is spot on. Approximately 375 OEM dual row IMSBs failed in the United States up through 2005.

[Walter White]

I have been running the single row bearings on a test jig to see how they are failing and may have something that may be interesting. With the standard single row bearing, the cage is usually made of two strips of metal riveted together to form the cage. My testing has shown that this type cage comes apart after only 10 to 15 minutes at about 5K rpm (no lubrication). So I transplanted a W type, or crown type cage used in the double row bearings into a single row bearing and ran it at 5K for 30 minutes with no signs of cage failure, and the balls still have a mirror finish (no lubrication). I am going to take the bearing apart to examine it and then get it back on the test jig for more running.

[Jake Raby]

Originally Posted by Walter White

I have been running the single row bearings on a test jig to see how they are failing and may have something that may be interesting. With the standard single row bearing, the cage is usually made of two strips of metal riveted together to form the cage. My testing has shown that this type cage comes apart after only 10 to 15 minutes at about 5K rpm (no lubrication). So I transplanted a W type, or crown type cage used in the double row bearings into a single row bearing and ran it at 5K for 30 minutes with no signs of cage failure, and the balls still have a mirror finish (no lubrication). I am going to take the bearing apart to examine it and then get it back on the test jig for more running.

Spinning the bearings unloaded doesn't tell you much of anything. You do realize how much engine RPM would equate to 5,000 IMS RPM, correct?

The only "jig" that works for this sort of testing or development is a running engine. Its called the M96.

[Walter White]

2 hours later, the balls have lost their mirror finish, and I can move the balls a little bit within their cage cells. But the cage still shows no signs of failing.
It's a little hard to keep the rpm up to 5k now because the bearing is beginning to vibrate a lot.

[Timco]

Originally Posted by Walter White

I have been running the single row bearings on a test jig to see how they are failing and may have something that may be interesting. With the standard single row bearing, the cage is usually made of two strips of metal riveted together to form the cage. My testing has shown that this type cage comes apart after only 10 to 15 minutes at about 5K rpm (no lubrication). So I transplanted a W type, or crown type cage used in the double row bearings into a single row bearing and ran it at 5K for 30 minutes with no signs of cage failure, and the balls still have a mirror finish (no lubrication). I am going to take the bearing apart to examine it and then get it back on the test jig for more running.

So if I run my engine with no oil, at the RPM that would spin the IMS at 5k RPM, your testing shows that it will last about 2.5 hours? (The bearing, not the pistons)

Seems more people change water pumps more often than IMS. Maybe test those?

[evomind]

Originally Posted by thom4782

JFP's implied guidance is spot on. Approximately 375 OEM dual row IMSBs failed in the United States up through 2005.

Out of how many manufactured? 375??? Lets see, every Boxster produced between the years 1997 and 1999 had a dual row, some cars from 2000 had a dual row. How many cars is that??
Sounds like just as much chance as cylinder linings cracking...Hurry, go rebuild your engine just in case.
I don't know guys.....