Duel Row Bearing Consensus ?

[southernstar]

jb92563, I think it is dangerous to look at the serial numbers listed in the settlement to conclude that an engine is a double-row: we know that it excludes cars built prior to May 4, 2001 even though cars built prior to that date can have the single-row bearing. It is also dangerous to look at the Porsche engine serial numbers that are listed in the Porsche parts catalogue as that is the CUTOFF date for dual-row bearings: inotherwords, while engines after that will be single-row, ones before that may also be single-row.

While the safest method of determining whether you have a dual or single row is to remove the transmission and inspect the cover/bearing, it kind of defeats the purpose. Once you have gone that far, you may as well replace the bearing.

What Porsche has made clear is that they did not introduce the single-row bearing when it first introduced the 2.7 and 3.2 engines; rather, it was a mid-2000 'upgrade'. AFter its introduction, they continued to use up their supply of dual-row bearings until that supply was exhausted and hence, for a period in the 2000 and 2001 MY, a car could have either. Presumably the LAST engines to have the dual-row bearing would be those listed in Porsche's parts catalogue :

2.7 engine serial number 12851 (last 5 sequential numbers)
3.2 engine serial number 11237 ( ditto)

I am assuming that the May 4th, 2001 cutoff date for inclusion in the settlement coincides with the installation of those engine numbers - ie., after that date ALL engines had single-row bearings. But who knows?

While Porsche has not given the specific date for the INTRODUCTION of the single-row bearing (apart from it being a mid-2000 change), I have opined in the dual versus single-row thread that it was at some point in the 2000 calendar year, rather than the model year: in Europe, where the car is manufactured, 'model years' are largely irrelevant - what we would call a 2000 MY Porsche is a 1999, if built in 1999.

If I am correct, then we can conclude that no engines manufactured in 1998 will have a dual-row bearing (denoted by a Y in the engine serial number prior to the last 5 sequential numbers).

We can also conclude that engines produced in calendar year 1999 ( denoted by a Z) would also have a dual-row, as they were produced prior to the introduction of the single-row in the year 2000.

Engines produced in calendar year 2000 and 2001 may or may not have a dual-row bearing, up until the serial numbers listed above.

The 2000 MY Boxster had a very long production run - while Porsche usually start production of its next MY in late July or August, production started in February of 1999 at the latest (as that is when the first 2.7's and 3.2's were shown at auto shows and made available for testing). Consequently, production of the 2000 MY Porsches continued for about 18 months until late July or August of 2000. Unless the engine was replaced/rebuilt, the only 2000 Boxsters that should have the single-row bearing, therefore, would be ones with engines manufactured in the year 2000. Some engines built in 2000, of course, will stiill have the dual-row bearing, but it is impossible to ascertain which.

The 2001 model year Boxsters, unless they had an engine built in 1999 installed, can have either bearing until the cut-off point for the dual-row in 2001, at the serial numbers listed above.

Again, I would be interested in hearing if anyone with an engine that was produced in 1998 or 1999, that has not been rebuilt, has a single-row bearing. If I am correct and Porsche was referring to an introduction of the sinlge-row during mid-calendar year 2000, rather than model year, there should be none. If they were referring to mid MY, then likely only the earliest engines (1998 production) would be absolutely safe.

Brad

[EssexPorsche]

Oh well JD,
Best bring the upgrade plan back to life - based on Brad's detailed analysis - you are in the never world my friend.

At least i knew mine was single so the choice was a simple one:dance::dance:

[Perfectlap]

A serviceable bearing should be replaced sooner than later. Good engine design can never accommodate using a sealed bearing where it can be easily prone to failure if proper oil and its duration are not perfectly maintained. This is a question mark with too many multiple owner Porsches. Especially if they followed the factory's dubious recommendations.

Personally, if I'm not the first owner or do not have all of the service records then I'm not waiting until the clutch wears out to replace the IMSB. I'm going to bump up that job because saving a few hundred dollars to max out clutch life is not worth guesstimating that the engine was looked after correctly. And since the IMSB/clutch job has utility -- you get a new clutch that can outlast the typical ownership period, I personally would want to put most of my miles on a new clutch replaced at my expense rather than gifting that to the next owner.

[southernstar]

Perfectlap, surely it depends upon the owner and whether you have a single or double-row bearing, as it dramatically effects the likelihood of failure. You are correct, of course, that the maintenance schedule (and in particular, oil change frequency) also makes a significant difference.

If your clutch is fine and you expect that the current value of your car is quite low (and they certainly seem to be even lower in the UK), many would choose not to install a new clutch and bearing as a prophylactic. Let's face it, if your car is worth only $8-12,000.00, then a clutch/bearing at about $3000.00 is between 25% and 37% of the value of the car. In addition, if you do install it as a prophylactic on a car you expect to sell in the near future, you are still, as you say,' gifting it' to the next owner unless the clutch needs replacement during the course of your ownership. Some original clutches have gone well over 100,000 miles without needing replacement.

Your view makes perfect sense for some, of course. Certainly, if someone is losing sleep over the IMS bearing, by all means either sell the car or get the bearing upgraded. All I and some others have been saying is that, particularly if you have a double-row bearing and, even more so if you have a good maintenance history (and my car has had the oil/filter changed annually at about 5000 miles, or less), then the odds of premature failure are extremely slim.

Brad

[fatmike]

From a purely financial perspective, should you replace the bearing?



Let's say your 2002 S is worth $12K. Odds of bearing blow out (if single row) are 10%. Would the car be worth $3K as a roller? If so, the expected value is:

90% of the time = $12K, 10% of the time $3K = $10,800 + $300 = $11,100.



IF you do replace the bearing, your car will be worth $12,000 100% of the time (or near enough to 100% for our thought exercise). The cost of the bearing is $3500.

So the EV in this case is: $12,000 - $3,500 = $8,500

Unless you believe that you will recover all, or substantially all, of the bearing cost when you sell the car it does not make financial sense. I do not believe that you will get $15,500 when you sell this car because you replace the bearing.

In this scenario, you are MUCH BETTER OFF not replacing your bearing and taking a chance.



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[EssexPorsche]

Unless you are lighting cigars with dead presidents - it still makes for a pretty pricey lawn ornament.

To some, a 986 isn't a cheap beater - its a dream.

Ask the Doc if he expects to get back the price of his restoration? or JD if he is under any illusion that he won't get corn holed on the re-sale of the Dangermobile.

To some, living the 986 dream is worth every penny of preventative maintenance.

I have spent close on £5k (sterling) on my car since January - why???? beacuse i love it and i can. Sure i could upgrade P car, sure i could change brand - but i don't want to. I want to keep my 986 mint and alive.

Anyways - plough your own furrow in life. Do what works for you. If its a simple maths equation the so be it, but i figure emiotion has to come into it somewhere.

[fatmike]

Essex - those are perfectly valid reasons


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[southernstar]

Interesting analysis, Fat mike. However, we can't lose sight of the fact that some people are literally losing sleep or at least, losing enjoyment of their cars because they are perpetually listening for suspicious noises and suspecting the worst. What value do you put on lost sleep/enjoyment of your car?

IMO this really is a personal choice and, let's face it, some people are more risk-averse than others. In any event, these discussions and the failure rates reported to Porsche should at least provide some assistance to some people in making a rational decision on the issue. And Essex, your reasons are not purely emotional, but rational. You obviously intend to keep your car for a long time and in those circumstances, as Perfectlap points out, it makes much more sense to spend money now to replace the clutch/upgrade the bearing, rather than wait.

Brad

[Dave S.]

I just had my single row 2003 IMSB replaced yesterday with 25k miles on the odometer. Bearing (and seal) was in perfect condition when removed, so maybe I was just paranoid. The cost including LN Engineering ceramic bearing, clutch and RMS was only $2386.00 plus tax.
I did however see a whole box of wasted IMS bearings and shafts at the independent shop I went to. Some were double row. I don't have any idea of how many miles were on them. Just sayin...