Another IMS bearing thread

[Walter White]

I got an oil seal that looks like it might fit into the end of the single row bearing IM shaft, as shown in my previous post.
It is a Beck-Arnley 052-3380. Can get these off eBay.

It is listed as 32 x 47 x 6 mm.
The outside diameter is about 2.865', where the bearing OD is 2.850", so it looks like it would be a nice snug fit into the shaft.
It is about .235" thick, but the edges are beveled so .200" is the required depth that will give maximum bite into the end of the IM shaft. I hope the distance from the bearing retaining snap ring to the end of the shaft is greater that .200". I know the end of the shaft is beveled so a little is lost on that bevel.
It is listed for a shaft diameter of 32 mm.
These seals are listed mostly as camshaft and tranny input shaft seals.

Some other seals that have a 47mm OD...
30 x 47 x 17 052-4002
32 x 47 x 10 052-3139
32 x 47 x 10 052-4005
32 x 47 x 8 052-3379
33 x 47 x 7 052-3288
35 x 47 x 7 052-3192
35 x 47 x 7 052-4000

[mikefocke]

Boxster, yes, no and maybe. The IMS will fail. The dual row less than the single. Some fail at 15k, some are still fine at 200k. There is no way of knowing where on the time versus failure probability curve your particular sample will fall. Nor is there any way of knowing how much risk your specific installer and his experience/skills/tools would add or subtract.

Roll the dice.

[thom4782]

All '99 Boxsters, with original engines, have dual row bearings.

Data from the IMS class action lawsuit showed less than 1% of OEM dual row bearings had failed.

Dual row OEM bearings fail typically when their outer seals degrade and leak.

Outer seals degrade when they are exposed to contaminated engine oil for long periods of time.

You may want to replace your dual row bearing before replacing the clutch if you haven't changed oil frequently (once a year or every 5000 miles whichever came first), you've let your car sit for long intervals between drives, or you/ve tended to take many drives where the engine hasn't run for 20 minutes or more at operating temperature.

If you're worried, replace the bearing now.

[boxster]

Originally Posted by thom4782

All '99 Boxsters, with original engines, have dual row bearings.

Data from the IMS class action lawsuit showed less than 1% of OEM dual row bearings had failed.

Dual row OEM bearings fail typically when their outer seals degrade and leak.

Outer seals degrade when they are exposed to contaminated engine oil for long periods of time.

You may want to replace your dual row bearing before replacing the clutch if you haven't changed oil frequently (once a year or every 5000 miles whichever came first), you've let your car sit for long intervals between drives, or you/ve tended to take many drives where the engine hasn't run for 20 minutes or more at operating temperature.

If you're worried, replace the bearing now.

I change the oil every year. I hardly use the car, sometimes it sits in the garage for about 2 months. When i change the oil my mechanic jokingly tells me that he feels like selling my old oil to someone else, as it's colour is that of brand new oil,sometimes with as little as 500 miles on it.
I still make it a rule to change it every year though, and inspect the magnetic drain plug and oil filter really well.
So do you think i should change the bearings because i don't use the car much?

[Walter White]

Originally Posted by boxster

I change the oil every year. I hardly use the car, sometimes it sits in the garage for about 2 months. When i change the oil my mechanic jokingly tells me that he feels like selling my old oil to someone else, as it's colour is that of brand new oil,sometimes with as little as 500 miles on it.

I had a suspicion that my mechanic was putting used oil in my car! It's yours!

[Walter White]

Bench-top testing isn't as futile as some would think. The first bearing I tested, I had no idea what was going to happen. I figured that maybe a few hours, maybe days, or even weeks, the bearing would begin to vibrate, wobble, screech and then maybe come apart with balls looking like raisins. But when that first piece of the cage came flying out of the bearing after only a matter of minutes it was a total surprise, I just didn't see that coming, literally. Then when I saw pictures of failed bearings with the cage broken in exactly the same areas, it got me thinking in a whole different direction.
Along those lines, I was wondering if the idea of drilling some holes in the IM shaft to equalize pressure has been bench-tested. It doesn't seem too difficult to set up. A piece of 2" PVC pipe, capped at both ends with a grommet in the center of one cap, slip a piece of tubing into the grommet (with a little grease) and connected to a manometer or a bottle of water. Spin the thing at maybe 3k rpm and see if pressure remains equal.

[thom4782]

Originally Posted by boxster

I change the oil every year. I hardly use the car, sometimes it sits in the garage for about 2 months. When i change the oil my mechanic jokingly tells me that he feels like selling my old oil to someone else, as it's colour is that of brand new oil,sometimes with as little as 500 miles on it.
I still make it a rule to change it every year though, and inspect the magnetic drain plug and oil filter really well.
So do you think i should change the bearings because i don't use the car much?

No. I'm simply saying that the evidence for OEM dual row bearings suggests that the odds of failure increase in cars with longer oil change intervals or low use. It's unclear by how much the odds. If your worried and plan to keep your car for a long time, upgrade the bearing and put the problem behind you.

[Jake Raby]

Keep experimenting for another decade, then we'll compare notes.

Cage failures are generally collateral damage.

[evomind]

Originally Posted by mikefocke

Boxster, yes, no and maybe. The IMS will fail. The dual row less than the single. Some fail at 15k, some are still fine at 200k. There is no way of knowing where on the time versus failure probability curve your particular sample will fall. Nor is there any way of knowing how much risk your specific installer and his experience/skills/tools would add or subtract.

Roll the dice.

The 99s are dual row, they are not prone to fail any more than any other part in the engine.
The rods will fail too, eventually.
I think its more PR to tell anyone with a Boxster to hurry out to your approved IMS bearing installer and have it switched out asap regardless of the year.

[JFP in PA]

Originally Posted by evomind

The 99s are dual row, they are not prone to fail any more than any other part in the engine.
The rods will fail too, eventually.
I think its more PR to tell anyone with a Boxster to hurry out to your approved IMS bearing installer and have it switched out asap regardless of the year.

We have a couple OEM dual row customer's that would disagree with you as they had to replace their engines when the "not prone to fail" IMS bearings killed their otherwise fine M96's.................

[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.

[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.....

[evomind]

Originally Posted by JFP in PA

We have a couple OEM dual row customer's that would disagree with you as they had to replace their engines when the "not prone to fail" IMS bearings killed their otherwise fine M96's.................

So based on a couple of bad ones EVERYONE should have it done ASAP???
And how much do you charge for that?

[JFP in PA]

Originally Posted by evomind

So based on a couple of bad ones EVERYONE should have it done ASAP???
And how much do you charge for that?

I am simply stating an observed fact: All ball bearing IMS units have some level of failure potential, and that the dual rows do fail and take the engines with them. We have had personal experience with failed single row, dual row, and even the oversized post 2005 units. The risk is real, and how people respond to those facts is entirely up to them and their personal level of risk aversion. Not everyone can afford to jump for a new bullet if their current engine suddenly dies, and some people intend to keep these cars for a long time, so they adjust their priorities accordingly. No one is holding a gun to their heads. And if you choose not to do anything about yours, well, that is your business.............

[evomind]

Look I realized its something that should be pointed out, but on models of cars where failure isn't prone I don't think the chicken little routine is necessary.
I think some people are over dramatizing this on the dual row cars.
Single row yes, I agree, much higher failure rate.

[Timco]

Originally Posted by evomind

Look I realized its something that should be pointed out, but on models of cars where failure isn't prone I don't think the chicken little routine is necessary.
I think some people are over dramatizing this on the dual row cars.
Single row yes, I agree, much higher failure rate.

You say that like every person drives the same way.

How many IMS online complaints have I read that started out with "I was doing 20 mph when it failed, and really never drive on the freeway at all, let alone in higher RPMs.." thinking that would help their case?

Two identical bearings. Two drivers. Two different potential results. Now, how many cars were made total?

[rp17]

I'm really interested on the thoughts of driving habits. Its been mentioned numerous times on drive it like you stole it but what particular driving habit causes the most load on the bearing?

[Walter White]

As my attempts to provide a better seal for the IMS bearing seem to be harder than I was hoping at this point, I have been thinking of ways to improve the flow of engine oil to the bearing. At times I have considered that if the pressure inside the IM shaft, or just behind the bearing, was lower than outside the shaft, oil mist and vapor might flow through the bearing at a higher rate than normal. Then I realized that if holes were drilled into the shaft, those holes may produce a low pressure inside the shaft when the shaft was turning.
I drilled a 1/16" hole in 2" pipe with a manometer connected to the pipe end and spun it on a lathe.
At 1K rpm, I got peaks of -.15 inches of water, and at 2.5K rpm I got peaks of -.3 inches of water pressure differential.
Drilling the hole bigger produced less pressure differential.
Drilling additional 1/16" holes had no affect on the initial pressure differential of the original 1/16" hole. But I would think that additional holes would provide high volumes of flow.
Not a lot of pressure differential. I wonder if it would even help any in increasing oil flow through the bearing.

[boxster]

This issue is driving me crazy. Today I started the car and stayed trying to listed for any noises. I couldnt hear anything from inside the car. then I went near the rear wheels and also couldnt hear anything. then I crawled under the car, and could hear some light ticking sounds, (tick tick tick tick.....) but I have no idea where its coming from exactly, or if it has anything to do with the IMS bearing. the noise is hardly noticeable. but if you crawl under the car and try to block out the exhaust sound, you can hear it. Any ideas what it could be? does it have to be the bearing? or is it normal for a boxer engine perhaps?