Duel Row Bearing Consensus ?
 

In light of the recent Porsche class-action settlement, is the consensus now if your vehicle has a dual row bearing - there's no need to do the IMSB retro-fit ?

Ohhhhhh..... I'm not touching this one!

Is there a popcorn icon available?:D

Why not ? It's a valid question.

I'm sorry Johnny... I'd like to know too. I just found out the other night that mine most likely has a double row. I think there has been double row failures but if the consensus is right they have less of a failure rate than my Ford F150's engine does.

Dual rows of bearing means twice the load bearing area and half the load on the bearing balls so if nothing else logic would dictate that in theory they should last longer.

I think keeping the bearings lubricated is the key to the matter so the seal on the bearings is probably the key.

Where is Jake, it would be interesting to hear how many dual row IMS failures he has had to deal with compared to the single row variety.

Knowing that your vehicle has a dual row bearing, has the recent data stemming from the Porsche settlement (know failure rate of only 1%) influenced your decision as to whether or not you will do the IMSB retro-fit ?

Yes, as I am not convinced that any of the retrofit bearings will necessarily have a better life-expectancy, or failure rate (and in fact, I am pretty confident that replacing your dual-row with the Pelican single-row and a spacer would be a retrograde step). That being said, when I eventually need to replace my clutch, since additional labour will be minimal, I will probably update with the LN bearing (and/or the pressurized oil system). At least I will then have a new bearing and, if nothing else, I suspect that eventual resale value would cover the cost of the bearing.

Brad

PS There is a link to a very lengthy thread under the pressurized oil thread from a couple of years ago - an interesting read as someone was positing that a dual-row should be inferior! What is significant, however, is that a number of people who replaced their dual-row bearings (and some with well in excess of 100,000 miles) found their original bearings to be in excellent condition.

I've always crossed my fingers and decided to wait until I needed a clutch job. My car only has 41k mi. so who knows when that'll be???

I'm in similar situation wherein my vehicle only has 20k original miles. So, waiting to do the clutch really isn't an option. In any case, I was prepared to do the the IMSB retro-fit immediately. However, the information that arose from this recent Porsche case has me thinking twice now ?

JD,

Well the recent data certainly influence my decision.

Mine was a single row and i am risk averese ....so retro-fit it was. However if i was sitting on a dual row. I wouldn't touch it unless i was in there anyway. Then for the extra cost i would just swap it out just like a cam belt on any other car.

The odds (assuming the are a correct reflection) are better than a Las Vegas casino win - Happy to take that.

What year is your 'S'?

I have a 2000 with presumably a dual row.

only 20K miles?
 

JD, even as a clandestine agent, you need to get out more and put some miles on the Dangermobile!
To answer your Q, I believe based on serial number (not visual inspection thus not 100% certain) that I have dual row, and will chance it at my current 87K miles and await the need for a new clutch, or god forbid, some other reason to go there.

Yep, that is my understanding. So despite the low mileage theories, if my car had frequent oil changes and a top drawer history and no sign of any leak down there.....if that was me, i'd leave it alone.

But that really is just my personal take on it: plenty of others will shoot me down.

This is the second such thread i have seen from you buddy, i think its starting to play on your mind or you are perhaps seeking affirmation on what others would do?

Either way - i hope you get the requisite responses that lead you to your decision

So Sean, for you the 'much less than 1%' hasn't provided some additional comfort in making that decision? To me, the most important aspect of the class-action suit IS the release of numbers concerning the respective failure rates of the dual-row and single-row IMS bearings. Remember, this was obtained from Porsche during the discovery process and the relative reliability of the dual-row IMS bearing was actually used by the plaintiffs in establishing their claim that the single-row bearing was negligently designed, rendering the engines unsuitable for their intended use. Porsche had every reason to inflate those numbers as the difference in failure rate - espeically considering the fact that the dual-row cars were older (and typically would have higher mileage) than the single-row cars, made the case against the single-row bearing a virtual slam-dunk for the plaintiffs.

Put it this way, a reported failure rate of much less than 1% is very low in the circumstances. Heck, it is still very low even if we substantially increase 'much less than 1%' TO 1%, to take into account those who never brought them into a Porsche dealership, or attempted to get compensation after failure. Consider the following:

1. The dual-row bearing cars are now all at least 11 years old; some (manufactured in 1996) are now 17 years old!
2. As a sports car, one would expect that many would have been subject to more 'spirited' driving than the average sedan; indeed, unlike most sedans, a significant percentage would have been used for track-days, autocross etc.
3. The reported rate is not limited by mileage - i.e., it would include cars with 200,000 miles or more! This is not just theory, we know of engines that have gone longer than that without IMSB failure.
4. Again, as the reported failure rate includes all vehicles, it also includes vehicles that were inadequately maintained and where, for example, the oil and filter were not changed regularly.

Considering the above, can anyone really say that the failure rate for the dual-row bearing is excessively high? Certainly, the lawyers for the plaintiff didn't think so; in fact, as mentioned above, they used that low failure rate as evidence of the difference between a well-designed and a negligently designed component.

Can a dual-row bearing fail? Yes, but so can the major engine components of any engine. For some, even this low failure rate will be enough of a concern for them to spend significant money to replace something which is likely not in need of replacement. To make an expensive prophylactic repair on what is now a relatively inexpensive car.

Let me tell you a story about a conversation I had recently with my Porsche factory-trained indy mechanic. I am taking a road trip in my 2000 2.7 this summer and, as I will be travelling to the Canadian east coast - an area that is not exactly overflowing with Porsche dealerships/mechanics, was inquiring about some potential repairs to be done as a prophylactic. In particular, as my car now has about 57,000 miles, I was considering replacing the water pump with a new Porsche facory part. I was already having the serpentine belt replaced and in the process, he had already checked out the pump and found no signs of leaks, or noises or play in the pulley consistent with pump bearing failure. When I asked if I should replace it anyway, in view of reported problems with these units, he said:

Yes, I have replaced a number of failed water pumps on these engines, although generally with higher mileage. Of course, I have also seen transmissions fail - would you like me to replace that too?

Brad

Brad, yes it has made me feel better about it!.... Much better. I believe you helped me the other night when I posted my engine VIN. I was having a hard time seeing as it was coated in fine crud. I have an annoying squeak in my clutch right now (throwout bearing?) that will need attention at some point, but it's not affecting the drivability of the car. Will I replace the imsb at the time of clutch replacement??? Still not sure? I just saw an ad on craigslist for a Boxster (Kansas City area) They were touting that the car had the old double row bearing and how that's a good thing etc. So the word is spreading.....

I am fairly certain that my '99 (128000 km) has a dual row bearing. I do not lose sleep or otherwise worry about it. I may change it out if/when I replace my clutch, which shouldn't be anytime soon, but I absolutely will not be going out of my way to change it sooner than that.

I do not buy in to all the doom-and-gloom, sky-is-falling, fear-mongering that we are regularly being bombarded with. I fell for it once and changed out what turned out to be a perfectly good water pump. Fool me once...

I am more concerned about Z-day than I am about my IMSB.

I'm on the verge of canceling my plans to do the IMSB retro-fit and simply stick with regular oil changes and monitoring the situation some more.

For my two cents worth, I just plan to treat the dual row bearing as a replacement item when I do the clutch. Whenever that occurs. Since I don't have the previously history I can't say when my clutch is expected to fail. Same thing for the ISMB. Who knows when it will fail much less if it will fail. If it happens, it happens. If it lasts until my clutch needs work I'll replace it then regardless of its condition. Until then, I just step on the pedal and don't worry about it and enjoy the ride.

JD, I've been waiting for some naysayer to suggest that with your moniker, 'Johnny Danger', they would have expected nothing less! Of course, I suppose the correct response would be to say that you are not 'Johnny Stupid'!
And MarkT, at least my mechanic talked me out of making the same mistake on my waterpump. Let's face it, if I had followed the advice of some and replaced my pump at 50,000 miles as a prophylactic, I'd be on my fourth pump by the time I reached the 200 and some thousand miles that Pedro ( of pedrosboard) has on his original waterpump!

If you have a dual-row bearing engine - especially one with a good service history with respect to oil changes (which by all accounts will bring the risk even lower than 'much less than 1%') - why not just drive the car as it was meant to be driven and ENJOY IT? When you need a new clutch, then make a decision. Afterall, the cost of additional labour is negligible at that point. Until then, keep in mind that there are a number of things that can go wrong with the car - including, as Raby points out, other potentially fatal engine problems that won't be corrected by a new IMS bearing.

Brad