Porsche used the ball bearing because it was the cheapest way to control radial and longitudinal loads. It killed two birds with one stone, and found them in a class action suit.

The dual row IMSB has TWO thrust control surfaces to assist with those longitudinal loads and that is a very welcome aspect of the dual row design. Two rows have proven to be better than one.

Like these new ideas on the Ixx issue. But they all bring me back to the old Insaro solution. What if you just installed that bearing, and with the back up bearing that it has, you never loose your engine. Sounds like the best fix especially now that the LN needs to serviced at 50k. What are your thoughts on this guys?

It's not new that the single row IMSB has a 50k mile service interval. That's been posted since it was first available.

I'd hold out a few weeks before making any purchases... Distributors already have their purchase orders submitted for the Generation 2 Retrofit kit.

Or just install the IMS Solution and remove the ball bearing from the equation totally.

The problem with Insaro is while you may have a back up bearing, that bearing won't keep all the debris from the primary bearing failing from taking out the remainder of the engine. Collateral damage from an IMSB failure is the determining factor for engine resurrection.

Generation 2!! I must have missed that Jake,whats the difference between gen1 and gen2. Jake do u believe that the newer larger 06 thru 08 bearing is really superior to the double row and have u seen or done any work on this newer design in respect to IMSB failure. I have searched the web and found none yet.

The Gen 2 retrofit details have not been disclosed publicly as of yet. This will occur after the first of the year as our focus is to get the units in the hands of our distributors before releasing the details.

The 06-08 IMSB have proven to be solid. Though we have seen some failures they only occur on-track.

I am very interested in more info on the Gen 2 IMSB. I was planning on getting mine done later this month but it sound like I might want to wait.

Jake: Will this Gen II be offered on the LN site for individual sale? - how would my local Indy shop purchase a Gen II bearing if I decide to go this route instead of purchasing the current retrofit (I'd assume they will still be for sale?) or scheduling to see you guys in Georgia for a solution?

Thanks

[QUOTE=I'd hold out a few weeks before making any purchases... Distributors already have their purchase orders submitted for the Generation 2 Retrofit kit.

[QUOTE=BED997;375035]Jake: Will this Gen II be offered on the LN site for individual sale? - how would my local Indy shop purchase a Gen II bearing if I decide to go this route instead of purchasing the current retrofit (I'd assume they will still be for sale?) or scheduling to see you guys in Georgia for a solution?

Thanks

[QUOTE=I'd hold out a few weeks before making any purchases... Distributors already have their purchase orders submitted for the Generation 2 Retrofit kit.[/QUOTE]

No, it will only be sold to our distributors for professional installation only. Thats the direction all the IMS products have gone, for very good reason. Since doing this last year our lives have been much less stressful and the complications related to retrofits have been cut by hundreds of percent.

Your local Indy can source the components from SSF Auto Parts, IMC, Worldpac and other major, well known distributors of Porsche parts.

Makes sense Jake - looking forward to seeing what you have come up with this time! I'll hold out for a little while longer before making a decision.

BTW - nice article in Panorama - downloaded it yesterday.

I believe that I am the only 986 owner on this forum with the Insaro bearing. It was a logical choice for me with my car being located in Spain, and my indi shop certified to install it, and experienced in doing so. I agree with Jake that taking the ball bearing out of the picture is the best option, but at the time I did the retrofit I wasn't yet familiar with the shop. Now that I know them I wouldn't hesitate to have them install the Solution. The backup bearing idea is, as Jake points out, probably not going to matter for saving the engine if it gets filled with ceramic debris. However, the primary bearing and shaft are quite beefy, so I hope to get a lot of years out of it before it or something else grenades. I can always upgrade to the Solution at my next clutch change, though since my car only gets driven a few thousand miles a year that will take a while. I'm proceeding to drive the -bleep- out of the car now without worrying... :cool:

I tried to install an SKF 11124 oil seal to a 6204 bearing, but it will not work.
It was a nice tight fit pressing the steel frame of the seal into the bearing outer race groove that holds the original seal. It was so tight it caused the frame to deform a bit on the adjacent side. This seal has two sealing surfaces, one for sealing oil, and another dust seal. The oil sealing part is on the inner race, and the dust seal is overhanging. The problem is the oil seal is too tight on the inner race. It creates a lot of drag and the inner race gets hot when run at a high speed. The seal eventually began to burn. But, a better seal may be possible. This exercise is to see if a better seal if possible on a bearing this small.
http://986forum.com/forums/uploads01...1386642956.jpg
http://986forum.com/forums/uploads01...1386642970.jpg

My next iteration of a bad idea. There may be enough space on the IM shaft after the clip that holds the bearing in place to press a grease seal into.
There are a number of seals available with a 47mm OD, which is the ID of the bearing holder.

http://986forum.com/forums/uploads01...1386724532.jpg

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

http://986forum.com/forums/uploads01...1387158734.jpg

Beck-Arnley 052-3380

I am looking for the dimension shown below, from a single row (2000 - 2004) IM shaft. It is the distance from the snap retainer ring to where the bevel starts on the end of the IM shaft.
Thanks in advance.http://986forum.com/forums/uploads01...1387568156.jpg

how does dual row compare
 

How does the earlier generation dual row bearings compare to the single row?
what is the rate of them failing compared to the single row?
from what ive read it seems that the dual row are not as prone to failing as the single row, any thoughts on this?

As measured from the rightmost face of the shaft

face of shaft to bend of bevel = 1.8 mm

face of shaft to snap ring 2.9 mm

so, 2.9 - 1.8 = 1.1 mm

Confident of a tolerance of 0.1 mm on all measurements

The single row failure rate is ~8x the dual failure rate.

Thanks again James. I was hoping for more depth in the bearing bore. It appeared there is significantly more depth on the bearing bore in photos, but photos can be misleading, or there may be variances in casting/machining.
Back to the drawing board.
I am following your work.

Thanks jamesp. I have a 99 box. I assume i have the dual row. Do you think i can rest my mind and take care of the situation when the clutch goes? I have 73k miles on the clock. Or would it be wise to just do it asap? Has the ims bearing issue come to a stage where the question is when it will go,rather than if?!

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.

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.

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.................

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

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.

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.

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?

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.....

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

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.

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.............

Walter White, Jake is spot on with the comment that spinning an unloaded bearing does not reflect what is happening in the engine. Ivory tower bearing life (all other things being equal) is related to load and RPM. The implication is that operating temperature lubrication, vibration, contamination are all nominal for the bearing. Take a look at bearing manufacturers design handbooks for more information. The reason I did not perform an L-10 calc for the IMSB was because the load would have to be an estimate making the result worthless. By the way, RPM is at 1/3 crank speed. As far as changing the IMSB, Porsche should have manned up early and declared it a maintenance item, particularly the single row :barf:. As has been pointed out below, every part of a car eventually fails, the trick is to understand required maintenance to head off collateral damage from failed parts. To reduce the chance of IMSB failure in my engine, the intermediate shaft was modified and the bearing replaced with a high temperature C3 single row bearing. The bearing will be changed out as if it were a timing belt. That means scheduled bearing replacement, something Porsche dealers should have been doing years ago.

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?

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?

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

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.

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.

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

Cage failures are generally collateral damage.